QgsVectorLayer Class Reference

Represents a vector layer which manages a vector based data sets. More...

#include <qgsvectorlayer.h>

Inheritance diagram for QgsVectorLayer:

Classes
struct	DeleteContext
	Context for cascade delete features. More...
struct	LayerOptions
	Setting options for loading vector layers. More...

Public Slots
bool	accept (QgsStyleEntityVisitorInterface *visitor) const override
Q_INVOKABLE void	deselect (const QgsFeatureIds &featureIds)
	Deselects features by their ID.
void	deselect (QgsFeatureId featureId)
	Deselects feature by its ID.
Qgis::SpatialIndexPresence	hasSpatialIndex () const override
Q_INVOKABLE void	removeSelection ()
	Clear selection.
void	reselect ()
	Reselects the previous set of selected features.
Q_INVOKABLE void	select (const QgsFeatureIds &featureIds)
	Selects features by their ID.
void	select (QgsFeatureId featureId)
	Selects feature by its ID.
virtual void	setTransformContext (const QgsCoordinateTransformContext &transformContext) override
	Sets the coordinate transform context to transformContext.
Q_INVOKABLE bool	startEditing ()
	Makes the layer editable.
virtual void	updateExtents (bool force=false)
	Update the extents for the layer.
Public Slots inherited from QgsMapLayer
void	emitStyleChanged ()
	Triggers an emission of the styleChanged() signal.
QgsProject *	project () const
	Returns the parent project if this map layer is added to a project.
void	setMaximumScale (double scale)
	Sets the maximum map scale (i.e.
void	setMinimumScale (double scale)
	Sets the minimum map scale (i.e.
void	setRefreshOnNofifyMessage (const QString &message)
	Set the notification message that triggers repaint If refresh on notification is enabled, the notification will triggerRepaint only if the notification message is equal to.
void	setRefreshOnNotifyEnabled (bool enabled)
	Set whether provider notification is connected to triggerRepaint.
void	setScaleBasedVisibility (bool enabled)
	Sets whether scale based visibility is enabled for the layer.
virtual void	setTransformContext (const QgsCoordinateTransformContext &transformContext)=0
	Sets the coordinate transform context to transformContext.
void	trigger3DUpdate ()
	Will advise any 3D maps that this layer requires to be updated in the scene.
void	triggerRepaint (bool deferredUpdate=false)
	Will advise the map canvas (and any other interested party) that this layer requires to be repainted.

Signals
void	afterCommitChanges ()
	Emitted after changes are committed to the data provider.
void	afterRollBack ()
	Emitted after changes are rolled back.
void	allowCommitChanged ()
	Emitted whenever the allowCommitChanged() property of this layer changes.
void	attributeAdded (int idx)
	Will be emitted, when a new attribute has been added to this vector layer.
void	attributeDeleted (int idx)
	Will be emitted, when an attribute has been deleted from this vector layer.
void	attributeValueChanged (QgsFeatureId fid, int idx, const QVariant &value)
	Emitted whenever an attribute value change is done in the edit buffer.
void	beforeAddingExpressionField (const QString &fieldName)
	Will be emitted, when an expression field is going to be added to this vector layer.
void	beforeCommitChanges (bool stopEditing)
	Emitted before changes are committed to the data provider.
void	beforeEditingStarted ()
	Emitted before editing on this layer is started.
void	beforeModifiedCheck () const
	Emitted when the layer is checked for modifications. Use for last-minute additions.
void	beforeRemovingExpressionField (int idx)
	Will be emitted, when an expression field is going to be deleted from this vector layer.
void	beforeRollBack ()
	Emitted before changes are rolled back.
void	committedAttributesAdded (const QString &layerId, const QList< QgsField > &addedAttributes)
	Emitted when attributes are added to the provider if not in transaction mode.
void	committedAttributesDeleted (const QString &layerId, const QgsAttributeList &deletedAttributes)
	Emitted when attributes are deleted from the provider if not in transaction mode.
void	committedAttributeValuesChanges (const QString &layerId, const QgsChangedAttributesMap &changedAttributesValues)
	Emitted when attribute value changes are saved to the provider if not in transaction mode.
void	committedFeaturesAdded (const QString &layerId, const QgsFeatureList &addedFeatures)
	Emitted when features are added to the provider if not in transaction mode.
void	committedFeaturesRemoved (const QString &layerId, const QgsFeatureIds &deletedFeatureIds)
	Emitted when features are deleted from the provider if not in transaction mode.
void	committedGeometriesChanges (const QString &layerId, const QgsGeometryMap &changedGeometries)
	Emitted when geometry changes are saved to the provider if not in transaction mode.
void	displayExpressionChanged ()
	Emitted when the display expression changes.
void	editCommandDestroyed ()
	Signal emitted, when an edit command is destroyed.
void	editCommandEnded ()
	Signal emitted, when an edit command successfully ended.
void	editCommandStarted (const QString &text)
	Signal emitted when a new edit command has been started.
void	editFormConfigChanged ()
	Will be emitted whenever the edit form configuration of this layer changes.
void	featureAdded (QgsFeatureId fid)
	Emitted when a new feature has been added to the layer.
void	featureBlendModeChanged (QPainter::CompositionMode blendMode)
	Signal emitted when setFeatureBlendMode() is called.
void	featureDeleted (QgsFeatureId fid)
	Emitted when a feature has been deleted.
void	featuresDeleted (const QgsFeatureIds &fids)
	Emitted when features have been deleted.
void	geometryChanged (QgsFeatureId fid, const QgsGeometry &geometry)
	Emitted whenever a geometry change is done in the edit buffer.
void	labelingFontNotFound (QgsVectorLayer *layer, const QString &fontfamily)
	Emitted when the font family defined for labeling layer is not found on system.
void	raiseError (const QString &msg)
	Signals an error related to this vector layer.
void	readCustomSymbology (const QDomElement &element, QString &errorMessage)
	Signal emitted whenever the symbology (QML-file) for this layer is being read.
void	readOnlyChanged ()
	Emitted when the read only state of this layer is changed.
void	selectionChanged (const QgsFeatureIds &selected, const QgsFeatureIds &deselected, bool clearAndSelect)
	Emitted when selection was changed.
void	subsetStringChanged ()
	Emitted when the layer's subset string has changed.
void	supportsEditingChanged ()
	Emitted when the read only state or the data provider of this layer is changed.
void	symbolFeatureCountMapChanged ()
	Emitted when the feature count for symbols on this layer has been recalculated.
void	updatedFields ()
	Emitted whenever the fields available from this layer have been changed.
void	writeCustomSymbology (QDomElement &element, QDomDocument &doc, QString &errorMessage) const
	Signal emitted whenever the symbology (QML-file) for this layer is being written.
Signals inherited from QgsMapLayer
void	autoRefreshIntervalChanged (int interval)
	Emitted when the auto refresh interval changes.
void	beforeResolveReferences (QgsProject *project)
	Emitted when all layers are loaded and references can be resolved, just before the references of this layer are resolved.
void	blendModeChanged (QPainter::CompositionMode blendMode)
	Signal emitted when the blend mode is changed, through QgsMapLayer::setBlendMode()
void	configChanged ()
	Emitted whenever the configuration is changed.
void	crsChanged ()
	Emit a signal that layer's CRS has been reset.
void	customPropertyChanged (const QString &key)
	Emitted when a custom property of the layer has been changed or removed.
void	dataChanged ()
	Data of layer changed.
void	dataSourceChanged ()
	Emitted whenever the layer's data source has been changed.
void	dependenciesChanged ()
	Emitted when dependencies are changed.
void	editingStarted ()
	Emitted when editing on this layer has started.
void	editingStopped ()
	Emitted when edited changes have been successfully written to the data provider.
void	flagsChanged ()
	Emitted when layer's flags have been modified.
void	isValidChanged ()
	Emitted when the validity of this layer changed.
void	layerModified ()
	Emitted when modifications has been done on layer.
void	legendChanged ()
	Signal emitted when legend of the layer has changed.
void	mapTipsEnabledChanged ()
	Emitted when map tips are enabled or disabled for the layer.
void	mapTipTemplateChanged ()
	Emitted when the map tip template changes.
void	metadataChanged ()
	Emitted when the layer's metadata is changed.
void	nameChanged ()
	Emitted when the name has been changed.
void	opacityChanged (double opacity)
	Emitted when the layer's opacity is changed, where opacity is a value between 0 (transparent) and 1 (opaque).
void	recalculateExtents () const
	This is used to send a request that any mapcanvas using this layer update its extents.
void	renderer3DChanged ()
	Signal emitted when 3D renderer associated with the layer has changed.
void	rendererChanged ()
	Signal emitted when renderer is changed.
void	repaintRequested (bool deferredUpdate=false)
	By emitting this signal the layer tells that either appearance or content have been changed and any view showing the rendered layer should refresh itself.
void	request3DUpdate ()
	Signal emitted when a layer requires an update in any 3D maps.
void	statusChanged (const QString &status)
	Emit a signal with status (e.g. to be caught by QgisApp and display a msg on status bar)
void	styleChanged ()
	Signal emitted whenever a change affects the layer's style.
void	styleLoaded (QgsMapLayer::StyleCategories categories)
	Emitted when a style has been loaded.
void	willBeDeleted ()
	Emitted in the destructor when the layer is about to be deleted, but it is still in a perfectly valid state: the last chance for other pieces of code for some cleanup if they use the layer.

Public Member Functions
	QgsVectorLayer (const QgsVectorLayer &rhs)=delete
	QgsVectorLayer cannot be copied.
	QgsVectorLayer (const QString &path=QString(), const QString &baseName=QString(), const QString &providerLib="ogr", const QgsVectorLayer::LayerOptions &options=QgsVectorLayer::LayerOptions())
	Constructor - creates a vector layer.
	~QgsVectorLayer () override
QgsActionManager *	actions ()
	Returns all layer actions defined on this layer.
const QgsActionManager *	actions () const
	Returns all layer actions defined on this layer.
bool	addAttribute (const QgsField &field)
	Add an attribute field (but does not commit it) returns true if the field was added.
int	addExpressionField (const QString &exp, const QgsField &fld)
	Add a new field which is calculated by the expression specified.
bool	addFeature (QgsFeature &feature, QgsFeatureSink::Flags flags=QgsFeatureSink::Flags()) FINAL
	Adds a single feature to the sink.
void	addFeatureRendererGenerator (QgsFeatureRendererGenerator *generator)
	Adds a new feature renderer generator to the layer.
bool	addFeatures (QgsFeatureList &features, QgsFeatureSink::Flags flags=QgsFeatureSink::Flags()) FINAL
	Adds a list of features to the sink.
bool	addJoin (const QgsVectorLayerJoinInfo &joinInfo)
	Joins another vector layer to this layer.
Q_INVOKABLE Qgis::GeometryOperationResult	addPart (const QgsPointSequence &ring)
	Adds a new part polygon to a multipart feature.
Q_DECL_DEPRECATED Qgis::GeometryOperationResult	addPart (const QList< QgsPointXY > &ring)
	Adds a new part polygon to a multipart feature.
Q_INVOKABLE Qgis::GeometryOperationResult	addPart (QgsCurve *ring)
Q_INVOKABLE Qgis::GeometryOperationResult	addRing (const QgsPointSequence &ring, QgsFeatureId *featureId=nullptr)
	Adds a ring to polygon/multipolygon features.
Q_DECL_DEPRECATED Qgis::GeometryOperationResult	addRing (const QVector< QgsPointXY > &ring, QgsFeatureId *featureId=nullptr)
	Adds a ring to polygon/multipolygon features.
Q_INVOKABLE Qgis::GeometryOperationResult	addRing (QgsCurve *ring, QgsFeatureId *featureId=nullptr)
	Adds a ring to polygon/multipolygon features (takes ownership)
int	addTopologicalPoints (const QgsGeometry &geom)
	Adds topological points for every vertex of the geometry.
int	addTopologicalPoints (const QgsPoint &p)
	Adds a vertex to segments which intersect point p but don't already have a vertex there.
int	addTopologicalPoints (const QgsPointSequence &ps)
	Adds a vertex to segments which intersect any of the points p but don't already have a vertex there.
Q_DECL_DEPRECATED int	addTopologicalPoints (const QgsPointXY &p)
	Adds a vertex to segments which intersect point p but don't already have a vertex there.
QVariant	aggregate (Qgis::Aggregate aggregate, const QString &fieldOrExpression, const QgsAggregateCalculator::AggregateParameters &parameters=QgsAggregateCalculator::AggregateParameters(), QgsExpressionContext *context=nullptr, bool *ok=nullptr, QgsFeatureIds *fids=nullptr, QgsFeedback *feedback=nullptr, QString *error=nullptr) const
	Calculates an aggregated value from the layer's features.
bool	allowCommit () const
	Controls, if the layer is allowed to commit changes.
QString	attributeAlias (int index) const
	Returns the alias of an attribute name or a null string if there is no alias.
QgsStringMap	attributeAliases () const
	Returns a map of field name to attribute alias.
QString	attributeDisplayName (int index) const
	Convenience function that returns the attribute alias if defined or the field name else.
QgsAttributeList	attributeList () const
	Returns list of attribute indexes.
QgsAttributeTableConfig	attributeTableConfig () const
	Returns the attribute table configuration object.
QgsAuxiliaryLayer *	auxiliaryLayer ()
	Returns the current auxiliary layer.
const QgsAuxiliaryLayer *	auxiliaryLayer () const
	Returns the current const auxiliary layer.
void	beginEditCommand (const QString &text)
	Create edit command for undo/redo operations.
Q_INVOKABLE QgsRectangle	boundingBoxOfSelected () const
	Returns the bounding box of the selected features. If there is no selection, QgsRectangle(0,0,0,0) is returned.
QString	capabilitiesString () const
	Capabilities for this layer, comma separated and translated.
bool	changeAttributeValue (QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue=QVariant(), bool skipDefaultValues=false)
	Changes an attribute value for a feature (but does not immediately commit the changes).
bool	changeAttributeValues (QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues=QgsAttributeMap(), bool skipDefaultValues=false)
	Changes attributes' values for a feature (but does not immediately commit the changes).
bool	changeGeometry (QgsFeatureId fid, QgsGeometry &geometry, bool skipDefaultValue=false)
	Changes a feature's geometry within the layer's edit buffer (but does not immediately commit the changes).
QgsVectorLayer *	clone () const override
	Returns a new instance equivalent to this one.
Q_INVOKABLE bool	commitChanges (bool stopEditing=true)
	Attempts to commit to the underlying data provider any buffered changes made since the last to call to startEditing().
QStringList	commitErrors () const
	Returns a list containing any error messages generated when attempting to commit changes to the layer.
QgsConditionalLayerStyles *	conditionalStyles () const
	Returns the conditional styles that are set for this layer.
QString	constraintDescription (int index) const
	Returns the descriptive name for the constraint expression for a specified field index.
QString	constraintExpression (int index) const
	Returns the constraint expression for for a specified field index, if set.
QgsVectorLayerFeatureCounter *	countSymbolFeatures (bool storeSymbolFids=false)
	Count features for symbols.
QgsExpressionContext	createExpressionContext () const FINAL
	This method needs to be reimplemented in all classes which implement this interface and return an expression context.
QgsExpressionContextScope *	createExpressionContextScope () const FINAL
	This method needs to be reimplemented in all classes which implement this interface and return an expression context scope.
QgsMapLayerRenderer *	createMapRenderer (QgsRenderContext &rendererContext) FINAL
	Returns new instance of QgsMapLayerRenderer that will be used for rendering of given context.
QgsAbstractProfileGenerator *	createProfileGenerator (const QgsProfileRequest &request) override
	Given a profile request, returns a new profile generator ready for generating elevation profiles.
QString	dataComment () const
	Returns a description for this layer as defined in the data provider.
const QgsVectorDataProvider *	dataProvider () const FINAL
	Returns the layer's data provider in a const-correct manner, it may be nullptr.
QgsVectorDataProvider *	dataProvider () FINAL
	Returns the layer's data provider, it may be nullptr.
QString	decodedSource (const QString &source, const QString &provider, const QgsReadWriteContext &context) const FINAL
	Called by readLayerXML(), used by derived classes to decode provider's specific data source from project files.
QVariant	defaultValue (int index, const QgsFeature &feature=QgsFeature(), QgsExpressionContext *context=nullptr) const
	Returns the calculated default value for the specified field index.
QgsDefaultValue	defaultValueDefinition (int index) const
	Returns the definition of the expression used when calculating the default value for a field.
virtual bool	deleteAttribute (int attr)
	Deletes an attribute field (but does not commit it).
bool	deleteAttributes (const QList< int > &attrs)
	Deletes a list of attribute fields (but does not commit it)
bool	deleteFeature (QgsFeatureId fid, DeleteContext *context=nullptr)
	Deletes a feature from the layer (but does not commit it).
bool	deleteFeatures (const QgsFeatureIds &fids, DeleteContext *context=nullptr)
	Deletes a set of features from the layer (but does not commit it)
Q_INVOKABLE bool	deleteSelectedFeatures (int *deletedCount=nullptr, QgsVectorLayer::DeleteContext *context=nullptr)
	Deletes the selected features.
Qgis::VectorEditResult	deleteVertex (QgsFeatureId featureId, int vertex)
	Deletes a vertex from a feature.
QSet< QgsMapLayerDependency >	dependencies () const FINAL
	Gets the list of dependencies.
void	destroyEditCommand ()
	Destroy active command and reverts all changes in it.
const QgsDiagramLayerSettings *	diagramLayerSettings () const
const QgsDiagramRenderer *	diagramRenderer () const
bool	diagramsEnabled () const
	Returns whether the layer contains diagrams which are enabled and should be drawn.
QString	displayExpression () const
	Returns the preview expression, used to create a human readable preview string.
QString	displayField () const
	This is a shorthand for accessing the displayExpression if it is a simple field.
Q_INVOKABLE QgsVectorLayerEditBuffer *	editBuffer ()
	Buffer with uncommitted editing operations. Only valid after editing has been turned on.
const QgsVectorLayerEditBuffer *	editBuffer () const
	Buffer with uncommitted editing operations.
QgsEditFormConfig	editFormConfig () const
	Returns the configuration of the form used to represent this vector layer.
QgsEditorWidgetSetup	editorWidgetSetup (int index) const
	The editor widget setup defines which QgsFieldFormatter and editor widget will be used for the field at index.
QgsMapLayerElevationProperties *	elevationProperties () override
	Returns the layer's elevation properties.
QString	encodedSource (const QString &source, const QgsReadWriteContext &context) const FINAL
	Called by writeLayerXML(), used by derived classes to encode provider's specific data source to project files.
void	endEditCommand ()
	Finish edit command and add it to undo/redo stack.
Q_DECL_DEPRECATED QSet< QString >	excludeAttributesWfs () const
	A set of attributes that are not advertised in WFS requests with QGIS server.
Q_DECL_DEPRECATED QSet< QString >	excludeAttributesWms () const
	A set of attributes that are not advertised in WMS requests with QGIS server.
QString	expressionField (int index) const
	Returns the expression used for a given expression field.
QgsRectangle	extent () const FINAL
	Returns the extent of the layer.
QgsBox3D	extent3D () const FINAL
	Returns the 3D extent of the layer.
QPainter::CompositionMode	featureBlendMode () const
	Returns the current blending mode for features.
long long	featureCount () const FINAL
	Returns feature count including changes which have not yet been committed If you need only the count of committed features call this method on this layer's provider.
long long	featureCount (const QString &legendKey) const
	Number of features rendered with specified legend key.
QList< const QgsFeatureRendererGenerator * >	featureRendererGenerators () const
	Returns a list of the feature renderer generators owned by the layer.
Qgis::FieldConfigurationFlags	fieldConfigurationFlags (int index) const
	Returns the configuration flags of the field at given index.
QgsFieldConstraints::Constraints	fieldConstraints (int fieldIndex) const
	Returns any constraints which are present for a specified field index.
QMap< QgsFieldConstraints::Constraint, QgsFieldConstraints::ConstraintStrength >	fieldConstraintsAndStrength (int fieldIndex) const
	Returns a map of constraint with their strength for a specific field of the layer.
QgsFields	fields () const FINAL
	Returns the list of fields of this layer.
QgsGeometryOptions *	geometryOptions () const
	Configuration and logic to apply automatically on any edit happening on this layer.
Q_INVOKABLE Qgis::GeometryType	geometryType () const
	Returns point, line or polygon.
QgsFeature	getFeature (QgsFeatureId fid) const
	Queries the layer for the feature with the given id.
QgsFeatureIterator	getFeatures (const QgsFeatureIds &fids)
	Queries the layer for the features with the given ids.
QgsFeatureIterator	getFeatures (const QgsFeatureRequest &request=QgsFeatureRequest()) const FINAL
	Queries the layer for features specified in request.
QgsFeatureIterator	getFeatures (const QgsRectangle &rectangle)
	Queries the layer for the features which intersect the specified rectangle.
QgsFeatureIterator	getFeatures (const QString &expression)
	Queries the layer for features matching a given expression.
QgsGeometry	getGeometry (QgsFeatureId fid) const
	Queries the layer for the geometry at the given id.
QgsFeatureIterator	getSelectedFeatures (QgsFeatureRequest request=QgsFeatureRequest()) const
	Returns an iterator of the selected features.
Qgis::FeatureAvailability	hasFeatures () const FINAL
	Determines if this vector layer has features.
bool	hasMapTips () const FINAL
	Returns true if the layer contains map tips.
QString	htmlMetadata () const FINAL
	Obtain a formatted HTML string containing assorted metadata for this layer.
bool	insertVertex (const QgsPoint &point, QgsFeatureId atFeatureId, int beforeVertex)
	Inserts a new vertex before the given vertex number, in the given ring, item (first number is index 0), and feature.
bool	insertVertex (double x, double y, QgsFeatureId atFeatureId, int beforeVertex)
	Inserts a new vertex before the given vertex number, in the given ring, item (first number is index 0), and feature.
Q_INVOKABLE void	invertSelection ()
	Selects not selected features and deselects selected ones.
Q_INVOKABLE void	invertSelectionInRectangle (QgsRectangle &rect)
	Inverts selection of features found within the search rectangle (in layer's coordinates)
bool	isAuxiliaryField (int index, int &srcIndex) const
	Returns true if the field comes from the auxiliary layer, false otherwise.
bool	isEditable () const FINAL
	Returns true if the provider is in editing mode.
bool	isEditCommandActive () const
	Tests if an edit command is active.
bool	isModified () const override
	Returns true if the provider has been modified since the last commit.
bool	isSpatial () const FINAL
	Returns true if this is a geometry layer and false in case of NoGeometry (table only) or UnknownGeometry.
bool	isSqlQuery () const
	Returns true if the layer is a query (SQL) layer.
QgsVectorLayerJoinBuffer *	joinBuffer ()
	Returns the join buffer object.
const QgsVectorLayerJoinBuffer *	joinBuffer () const
	Returns a const pointer on join buffer object.
QgsAbstractVectorLayerLabeling *	labeling ()
	Access to labeling configuration.
const QgsAbstractVectorLayerLabeling *	labeling () const
	Access to const labeling configuration.
bool	labelsEnabled () const
	Returns whether the layer contains labels which are enabled and should be drawn.
bool	loadAuxiliaryLayer (const QgsAuxiliaryStorage &storage, const QString &key=QString())
	Loads the auxiliary layer for this vector layer.
QString	loadDefaultStyle (bool &resultFlag) FINAL
	Retrieve the default style for this layer if one exists (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
QVariant	maximumValue (int index) const FINAL
	Returns the maximum value for an attribute column or an invalid variant in case of error.
void	minimumAndMaximumValue (int index, QVariant &minimum, QVariant &maximum) const
	Calculates both the minimum and maximum value for an attribute column.
QVariant	minimumValue (int index) const FINAL
	Returns the minimum value for an attribute column or an invalid variant in case of error.
Q_INVOKABLE void	modifySelection (const QgsFeatureIds &selectIds, const QgsFeatureIds &deselectIds)
	Modifies the current selection on this layer.
bool	moveVertex (const QgsPoint &p, QgsFeatureId atFeatureId, int atVertex)
	Moves the vertex at the given position number, ring and item (first number is index 0), and feature to the given coordinates.
bool	moveVertex (double x, double y, QgsFeatureId atFeatureId, int atVertex)
	Moves the vertex at the given position number, ring and item (first number is index 0), and feature to the given coordinates.
QgsVectorLayer &	operator= (QgsVectorLayer const &rhs)=delete
	QgsVectorLayer cannot be copied.
QgsAttributeList	primaryKeyAttributes () const
	Returns the list of attributes which make up the layer's primary keys.
bool	readExtentFromXml () const
	Returns true if the extent is read from the XML document when data source has no metadata, false if it's the data provider which determines it.
bool	readSld (const QDomNode &node, QString &errorMessage) FINAL
bool	readStyle (const QDomNode &node, QString &errorMessage, QgsReadWriteContext &context, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories) FINAL
bool	readSymbology (const QDomNode &layerNode, QString &errorMessage, QgsReadWriteContext &context, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories) FINAL
bool	readXml (const QDomNode &layer_node, QgsReadWriteContext &context) FINAL
	Reads vector layer specific state from project file Dom node.
QList< QgsRelation >	referencingRelations (int idx) const
	Returns the layer's relations, where the foreign key is on this layer.
void	reload () FINAL
	Synchronises with changes in the datasource.
void	removeExpressionField (int index)
	Removes an expression field.
void	removeFeatureRendererGenerator (const QString &id)
	Removes the feature renderer with matching id from the layer.
void	removeFieldAlias (int index)
	Removes an alias (a display name) for attributes to display in dialogs.
void	removeFieldConstraint (int index, QgsFieldConstraints::Constraint constraint)
	Removes a constraint for a specified field index.
bool	removeJoin (const QString &joinLayerId)
	Removes a vector layer join.
bool	renameAttribute (int index, const QString &newName)
	Renames an attribute field (but does not commit it).
QgsFeatureRenderer *	renderer ()
	Returns the feature renderer used for rendering the features in the layer in 2D map views.
const QgsFeatureRenderer *	renderer () const
	Returns the feature renderer used for rendering the features in the layer in 2D map views.
void	resolveReferences (QgsProject *project) FINAL
	Resolves references to other layers (kept as layer IDs after reading XML) into layer objects.
Q_INVOKABLE bool	rollBack (bool deleteBuffer=true)
	Stops a current editing operation and discards any uncommitted edits.
Q_INVOKABLE void	selectAll ()
	Select all the features.
Q_INVOKABLE void	selectByExpression (const QString &expression, Qgis::SelectBehavior behavior=Qgis::SelectBehavior::SetSelection, QgsExpressionContext *context=nullptr)
	Selects matching features using an expression.
Q_INVOKABLE void	selectByIds (const QgsFeatureIds &ids, Qgis::SelectBehavior behavior=Qgis::SelectBehavior::SetSelection)
	Selects matching features using a list of feature IDs.
Q_INVOKABLE void	selectByRect (QgsRectangle &rect, Qgis::SelectBehavior behavior=Qgis::SelectBehavior::SetSelection)
	Selects features found within the search rectangle (in layer's coordinates)
int	selectedFeatureCount () const
	Returns the number of features that are selected in this layer.
Q_INVOKABLE const QgsFeatureIds &	selectedFeatureIds () const
	Returns a list of the selected features IDs in this layer.
Q_INVOKABLE QgsFeatureList	selectedFeatures () const
	Returns a copy of the user-selected features.
QgsMapLayerSelectionProperties *	selectionProperties () override
	Returns the layer's selection properties.
void	setAllowCommit (bool allowCommit)
	Controls, if the layer is allowed to commit changes.
void	setAttributeTableConfig (const QgsAttributeTableConfig &attributeTableConfig)
	Sets the attribute table configuration object.
void	setAuxiliaryLayer (QgsAuxiliaryLayer *layer=nullptr)
	Sets the current auxiliary layer.
void	setConstraintExpression (int index, const QString &expression, const QString &description=QString())
	Sets the constraint expression for the specified field index.
void	setCoordinateSystem ()
	Setup the coordinate system transformation for the layer.
void	setDefaultValueDefinition (int index, const QgsDefaultValue &definition)
	Sets the definition of the expression to use when calculating the default value for a field.
bool	setDependencies (const QSet< QgsMapLayerDependency > &layers) FINAL
	Sets the list of dependencies.
void	setDiagramLayerSettings (const QgsDiagramLayerSettings &s)
void	setDiagramRenderer (QgsDiagramRenderer *r)
	Sets diagram rendering object (takes ownership)
void	setDisplayExpression (const QString &displayExpression)
	Set the preview expression, used to create a human readable preview string.
void	setEditFormConfig (const QgsEditFormConfig &editFormConfig)
	Sets the editFormConfig (configuration) of the form used to represent this vector layer.
void	setEditorWidgetSetup (int index, const QgsEditorWidgetSetup &setup)
	The editor widget setup defines which QgsFieldFormatter and editor widget will be used for the field at index.
Q_DECL_DEPRECATED void	setExcludeAttributesWfs (const QSet< QString > &att)
	A set of attributes that are not advertised in WFS requests with QGIS server.
Q_DECL_DEPRECATED void	setExcludeAttributesWms (const QSet< QString > &att)
	A set of attributes that are not advertised in WMS requests with QGIS server.
void	setFeatureBlendMode (QPainter::CompositionMode blendMode)
	Sets the blending mode used for rendering each feature.
void	setFieldAlias (int index, const QString &aliasString)
	Sets an alias (a display name) for attributes to display in dialogs.
void	setFieldConfigurationFlag (int index, Qgis::FieldConfigurationFlag flag, bool active)
	Sets the given configuration flag for the field at given index to be active or not.
void	setFieldConfigurationFlags (int index, Qgis::FieldConfigurationFlags flags)
	Sets the configuration flags of the field at given index.
void	setFieldConstraint (int index, QgsFieldConstraints::Constraint constraint, QgsFieldConstraints::ConstraintStrength strength=QgsFieldConstraints::ConstraintStrengthHard)
	Sets a constraint for a specified field index.
void	setFieldSplitPolicy (int index, Qgis::FieldDomainSplitPolicy policy)
	Sets a split policy for the field with the specified index.
void	setLabeling (QgsAbstractVectorLayerLabeling *labeling)
	Sets labeling configuration.
void	setLabelsEnabled (bool enabled)
	Sets whether labels should be enabled for the layer.
void	setProviderEncoding (const QString &encoding)
	Sets the text encoding of the data provider.
void	setReadExtentFromXml (bool readExtentFromXml)
	Flag allowing to indicate if the extent has to be read from the XML document when data source has no metadata or if the data provider has to determine it.
bool	setReadOnly (bool readonly=true)
	Makes layer read-only (editing disabled) or not.
void	setRenderer (QgsFeatureRenderer *r)
	Sets the feature renderer which will be invoked to represent this layer in 2D map views.
void	setSimplifyMethod (const QgsVectorSimplifyMethod &simplifyMethod)
	Sets the simplification settings for fast rendering of features.
virtual bool	setSubsetString (const QString &subset)
	Sets the string (typically sql) used to define a subset of the layer.
void	setWeakRelations (const QList< QgsWeakRelation > &relations)
	Sets the layer's weak relations.
bool	simplifyDrawingCanbeApplied (const QgsRenderContext &renderContext, QgsVectorSimplifyMethod::SimplifyHint simplifyHint) const
	Returns whether the VectorLayer can apply the specified simplification hint.
const QgsVectorSimplifyMethod &	simplifyMethod () const
	Returns the simplification settings for fast rendering of features.
QgsCoordinateReferenceSystem	sourceCrs () const FINAL
	Returns the coordinate reference system for features in the source.
QgsRectangle	sourceExtent () const FINAL
	Returns the extent of all geometries from the source.
QgsBox3D	sourceExtent3D () const FINAL
	Returns the 3D extent of all geometries from the source.
QString	sourceName () const FINAL
	Returns a friendly display name for the source.
Q_INVOKABLE Qgis::GeometryOperationResult	splitFeatures (const QgsCurve *curve, QgsPointSequence &topologyTestPoints, bool preserveCircular=false, bool topologicalEditing=false)
	Splits features cut by the given curve.
Q_INVOKABLE Qgis::GeometryOperationResult	splitFeatures (const QgsPointSequence &splitLine, bool topologicalEditing=false)
	Splits features cut by the given line.
Q_DECL_DEPRECATED Qgis::GeometryOperationResult	splitFeatures (const QVector< QgsPointXY > &splitLine, bool topologicalEditing=false)
	Splits features cut by the given line.
Q_INVOKABLE Qgis::GeometryOperationResult	splitParts (const QgsPointSequence &splitLine, bool topologicalEditing=false)
	Splits parts cut by the given line.
Q_DECL_DEPRECATED Qgis::GeometryOperationResult	splitParts (const QVector< QgsPointXY > &splitLine, bool topologicalEditing=false)
	Splits parts cut by the given line.
QString	storageType () const
	Returns the permanent storage type for this layer as a friendly name.
QgsStoredExpressionManager *	storedExpressionManager ()
	Returns the manager of the stored expressions for this layer.
virtual QString	subsetString () const
	Returns the string (typically sql) used to define a subset of the layer.
bool	supportsEditing () const override
	Returns whether the layer supports editing or not.
QgsFeatureIds	symbolFeatureIds (const QString &legendKey) const
	Ids of features rendered with specified legend key.
QgsMapLayerTemporalProperties *	temporalProperties () override
	Returns the layer's temporal properties.
Q_INVOKABLE int	translateFeature (QgsFeatureId featureId, double dx, double dy)
	Translates feature by dx, dy.
QStringList	uniqueStringsMatching (int index, const QString &substring, int limit=-1, QgsFeedback *feedback=nullptr) const
	Returns unique string values of an attribute which contain a specified subset string.
QSet< QVariant >	uniqueValues (int fieldIndex, int limit=-1) const FINAL
	Calculates a list of unique values contained within an attribute in the layer.
void	updateExpressionField (int index, const QString &exp)
	Changes the expression used to define an expression based (virtual) field.
bool	updateFeature (QgsFeature &feature, bool skipDefaultValues=false)
	Updates an existing feature in the layer, replacing the attributes and geometry for the feature with matching QgsFeature::id() with the attributes and geometry from feature.
void	updateFields ()
	Will regenerate the fields property of this layer by obtaining all fields from the dataProvider, joined fields and virtual fields.
const QList< QgsVectorLayerJoinInfo >	vectorJoins () const
Qgis::VectorLayerTypeFlags	vectorLayerTypeFlags () const
	Returns the vector layer type flags.
QList< QgsWeakRelation >	weakRelations () const
	Returns the layer's weak relations as specified in the layer's style.
Q_INVOKABLE Qgis::WkbType	wkbType () const FINAL
	Returns the WKBType or WKBUnknown in case of error.
bool	writeSld (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QVariantMap &props=QVariantMap()) const
	Writes the symbology of the layer into the document provided in SLD 1.1 format.
bool	writeStyle (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &context, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories) const FINAL
bool	writeSymbology (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &context, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories) const FINAL
bool	writeXml (QDomNode &layer_node, QDomDocument &doc, const QgsReadWriteContext &context) const FINAL
	Writes vector layer specific state to project file Dom node.
Public Member Functions inherited from QgsMapLayer
	QgsMapLayer (Qgis::LayerType type=Qgis::LayerType::Vector, const QString &name=QString(), const QString &source=QString())
	Constructor for QgsMapLayer.
	QgsMapLayer (QgsMapLayer const &)=delete
	QgsMapLayer cannot be copied.
	~QgsMapLayer () override
QString	abstract () const
	Returns the abstract of the layer used by QGIS Server in GetCapabilities request.
virtual bool	accept (QgsStyleEntityVisitorInterface *visitor) const
	Accepts the specified symbology visitor, causing it to visit all symbols associated with the layer.
QString	attribution () const
	Returns the attribution of the layer used by QGIS Server in GetCapabilities request.
QString	attributionUrl () const
	Returns the attribution URL of the layer used by QGIS Server in GetCapabilities request.
int	autoRefreshInterval () const
	Returns the auto refresh interval (in milliseconds).
Qgis::AutoRefreshMode	autoRefreshMode () const
	Returns the layer's automatical refresh mode.
QPainter::CompositionMode	blendMode () const
	Returns the current blending mode for a layer.
QgsCoordinateReferenceSystem	crs () const
	Returns the layer's spatial reference system.
template<class T >
T	customEnumProperty (const QString &key, const T &defaultValue)
	Returns the property value for a property based on an enum.
template<class T >
T	customFlagProperty (const QString &key, const T &defaultValue)
	Returns the property value for a property based on a flag.
const QgsObjectCustomProperties &	customProperties () const
	Read all custom properties from layer.
Q_INVOKABLE QVariant	customProperty (const QString &value, const QVariant &defaultValue=QVariant()) const
	Read a custom property from layer.
Q_INVOKABLE QStringList	customPropertyKeys () const
	Returns list of all keys within custom properties.
QString	dataUrl () const
	Returns the DataUrl of the layer used by QGIS Server in GetCapabilities request.
QString	dataUrlFormat () const
	Returns the DataUrl format of the layer used by QGIS Server in GetCapabilities request.
virtual bool	deleteStyleFromDatabase (const QString &styleId, QString &msgError)
	Deletes a style from the database.
virtual QgsError	error () const
	Gets current status error.
void	exportNamedMetadata (QDomDocument &doc, QString &errorMsg) const
	Export the current metadata of this layer as named metadata in a QDomDocument.
virtual void	exportNamedStyle (QDomDocument &doc, QString &errorMsg, const QgsReadWriteContext &context=QgsReadWriteContext(), QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories) const
	Export the properties of this layer as named style in a QDomDocument.
virtual void	exportSldStyle (QDomDocument &doc, QString &errorMsg) const
	Export the properties of this layer as SLD style in a QDomDocument.
virtual void	exportSldStyleV2 (QDomDocument &doc, QString &errorMsg, const QgsSldExportContext &exportContext) const
	Export the properties of this layer as SLD style in a QDomDocument.
QgsMapLayer::LayerFlags	flags () const
	Returns the flags for this layer.
virtual QString	getStyleFromDatabase (const QString &styleId, QString &msgError)
	Returns the named style corresponding to style id provided.
Q_DECL_DEPRECATED bool	hasAutoRefreshEnabled () const
	Returns true if auto refresh is enabled for the layer.
bool	hasScaleBasedVisibility () const
	Returns whether scale based visibility is enabled for the layer.
QString	id () const
	Returns the layer's unique ID, which is used to access this layer from QgsProject.
bool	importNamedMetadata (QDomDocument &document, QString &errorMessage)
	Import the metadata of this layer from a QDomDocument.
virtual bool	importNamedStyle (QDomDocument &doc, QString &errorMsg, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories)
	Import the properties of this layer from a QDomDocument.
bool	isInScaleRange (double scale) const
	Tests whether the layer should be visible at the specified scale.
bool	isRefreshOnNotifyEnabled () const
	Returns true if the refresh on provider nofification is enabled.
virtual bool	isTemporary () const
	Returns true if the layer is considered a temporary layer.
bool	isValid () const
	Returns the status of the layer.
QString	keywordList () const
	Returns the keyword list of the layer used by QGIS Server in GetCapabilities request.
QgsMapLayerLegend *	legend () const
	Can be nullptr.
QString	legendPlaceholderImage () const
	Returns path to the placeholder image or an empty string if a generated legend is shown.
QString	legendUrl () const
	Returns the URL for the layer's legend.
QString	legendUrlFormat () const
	Returns the format for a URL based layer legend.
virtual int	listStylesInDatabase (QStringList &ids, QStringList &names, QStringList &descriptions, QString &msgError)
	Lists all the style in db split into related to the layer and not related to.
virtual QString	loadDefaultMetadata (bool &resultFlag)
	Retrieve the default metadata for this layer if one exists (either as a .qmd file on disk or as a record in the users metadata table in their personal qgis.db)
virtual QString	loadNamedMetadata (const QString &uri, bool &resultFlag)
	Retrieve a named metadata for this layer if one exists (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db)
bool	loadNamedMetadataFromDatabase (const QString &db, const QString &uri, QString &qmd)
	Retrieve a named metadata for this layer from a sqlite database.
virtual QString	loadNamedStyle (const QString &theURI, bool &resultFlag, bool loadFromLocalDb, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories)
	Loads a named style from file/local db/datasource db.
virtual QString	loadNamedStyle (const QString &uri, bool &resultFlag, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories)
	Retrieve a named style for this layer if one exists (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
virtual bool	loadNamedStyleFromDatabase (const QString &db, const QString &uri, QString &qml)
	Retrieve a named style for this layer from a sqlite database.
virtual QString	loadSldStyle (const QString &uri, bool &resultFlag)
	Attempts to style the layer using the formatting from an SLD type file.
bool	mapTipsEnabled () const
	Returns true if map tips are enabled for this layer.
QString	mapTipTemplate () const
	The mapTip is a pretty, html representation for feature information.
double	maximumScale () const
	Returns the maximum map scale (i.e.
virtual const QgsLayerMetadata &	metadata () const
	Returns a reference to the layer's metadata store.
virtual QString	metadataUri () const
	Retrieve the metadata URI for this layer (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db)
Q_DECL_DEPRECATED QString	metadataUrl () const
	Returns the metadata URL of the layer used by QGIS Server in GetCapabilities request.
Q_DECL_DEPRECATED QString	metadataUrlFormat () const
	Returns the metadata format of the layer used by QGIS Server in GetCapabilities request.
Q_DECL_DEPRECATED QString	metadataUrlType () const
	Returns the metadata type of the layer used by QGIS Server in GetCapabilities request.
double	minimumScale () const
	Returns the minimum map scale (i.e.
QString	name () const
	Returns the display name of the layer.
virtual double	opacity () const
	Returns the opacity for the layer, where opacity is a value between 0 (totally transparent) and 1.0 (fully opaque).
QgsMapLayer &	operator= (QgsMapLayer const &)=delete
	QgsMapLayer cannot be copied.
QString	originalXmlProperties () const
	Returns the XML properties of the original layer as they were when the layer was first read from the project file.
virtual Qgis::MapLayerProperties	properties () const
	Returns the map layer properties of this layer.
QString	providerType () const
	Returns the provider type (provider key) for this layer.
QString	publicSource (bool hidePassword=false) const
	Gets a version of the internal layer definition that has sensitive bits removed (for example, the password).
bool	readLayerXml (const QDomElement &layerElement, QgsReadWriteContext &context, QgsMapLayer::ReadFlags flags=QgsMapLayer::ReadFlags(), QgsDataProvider *preloadedProvider=nullptr)
	Sets state from DOM document.
bool	readOnly () const
	Returns if this layer is read only.
virtual bool	readStyle (const QDomNode &node, QString &errorMessage, QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories)
	Read the style for the current layer from the DOM node supplied.
virtual bool	readSymbology (const QDomNode &node, QString &errorMessage, QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories)=0
	Read the symbology for the current layer from the DOM node supplied.
QString	refreshOnNotifyMessage () const
	Returns the message that should be notified by the provider to triggerRepaint.
void	removeCustomProperty (const QString &key)
	Remove a custom property from layer.
QgsAbstract3DRenderer *	renderer3D () const
	Returns 3D renderer associated with the layer.
virtual QString	saveDefaultMetadata (bool &resultFlag)
	Save the current metadata of this layer as the default metadata (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db)
virtual Q_DECL_DEPRECATED QString	saveDefaultStyle (bool &resultFlag)
	Save the properties of this layer as the default style (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
virtual QString	saveDefaultStyle (bool &resultFlag, StyleCategories categories)
	Save the properties of this layer as the default style (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
QString	saveNamedMetadata (const QString &uri, bool &resultFlag)
	Save the current metadata of this layer as a named metadata (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db)
virtual QString	saveNamedStyle (const QString &uri, bool &resultFlag, StyleCategories categories=AllStyleCategories)
	Save the properties of this layer as a named style (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
virtual QString	saveSldStyle (const QString &uri, bool &resultFlag) const
	Saves the properties of this layer to an SLD format file.
virtual QString	saveSldStyleV2 (bool &resultFlag, const QgsSldExportContext &exportContext) const
	Saves the properties of this layer to an SLD format file.
virtual void	saveStyleToDatabase (const QString &name, const QString &description, bool useAsDefault, const QString &uiFileContent, QString &msgError, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories)
	Saves named and sld style of the layer to the style table in the db.
QgsMapLayerServerProperties *	serverProperties ()
	Returns QGIS Server Properties for the map layer.
const QgsMapLayerServerProperties *	serverProperties () const
	Returns QGIS Server Properties const for the map layer.
void	setAbstract (const QString &abstract)
	Sets the abstract of the layer used by QGIS Server in GetCapabilities request.
void	setAttribution (const QString &attrib)
	Sets the attribution of the layer used by QGIS Server in GetCapabilities request.
void	setAttributionUrl (const QString &attribUrl)
	Sets the attribution URL of the layer used by QGIS Server in GetCapabilities request.
Q_DECL_DEPRECATED void	setAutoRefreshEnabled (bool enabled)
	Sets whether auto refresh is enabled for the layer.
void	setAutoRefreshInterval (int interval)
	Sets the auto refresh interval (in milliseconds) for the layer.
void	setAutoRefreshMode (Qgis::AutoRefreshMode mode)
	Sets the automatic refresh mode for the layer.
void	setBlendMode (QPainter::CompositionMode blendMode)
	Set the blending mode used for rendering a layer.
void	setCrs (const QgsCoordinateReferenceSystem &srs, bool emitSignal=true)
	Sets layer's spatial reference system.
template<class T >
void	setCustomEnumProperty (const QString &key, const T &value)
	Set the value of a property based on an enum.
template<class T >
void	setCustomFlagProperty (const QString &key, const T &value)
	Set the value of a property based on a flag.
void	setCustomProperties (const QgsObjectCustomProperties &properties)
	Set custom properties for layer.
Q_INVOKABLE void	setCustomProperty (const QString &key, const QVariant &value)
	Set a custom property for layer.
void	setDataSource (const QString &dataSource, const QString &baseName, const QString &provider, bool loadDefaultStyleFlag=false)
	Updates the data source of the layer.
void	setDataSource (const QString &dataSource, const QString &baseName, const QString &provider, const QgsDataProvider::ProviderOptions &options, bool loadDefaultStyleFlag=false)
	Updates the data source of the layer.
void	setDataSource (const QString &dataSource, const QString &baseName, const QString &provider, const QgsDataProvider::ProviderOptions &options, QgsDataProvider::ReadFlags flags)
	Updates the data source of the layer.
void	setDataUrl (const QString &dataUrl)
	Sets the DataUrl of the layer used by QGIS Server in GetCapabilities request.
void	setDataUrlFormat (const QString &dataUrlFormat)
	Sets the DataUrl format of the layer used by QGIS Server in GetCapabilities request.
void	setFlags (QgsMapLayer::LayerFlags flags)
	Returns the flags for this layer.
void	setKeywordList (const QString &keywords)
	Sets the keyword list of the layer used by QGIS Server in GetCapabilities request.
virtual void	setLayerOrder (const QStringList &layers)
	Reorders the previously selected sublayers of this layer from bottom to top.
void	setLegend (QgsMapLayerLegend *legend)
	Assign a legend controller to the map layer.
void	setLegendPlaceholderImage (const QString &imgPath)
	Set placeholder image for legend.
void	setLegendUrl (const QString &legendUrl)
	Sets the URL for the layer's legend.
void	setLegendUrlFormat (const QString &legendUrlFormat)
	Sets the format for a URL based layer legend.
void	setMapTipsEnabled (bool enabled)
	Enable or disable map tips for this layer.
void	setMapTipTemplate (const QString &mapTipTemplate)
	The mapTip is a pretty, html representation for feature information.
virtual void	setMetadata (const QgsLayerMetadata &metadata)
	Sets the layer's metadata store.
Q_DECL_DEPRECATED void	setMetadataUrl (const QString &metaUrl)
	Sets the metadata URL of the layer used by QGIS Server in GetCapabilities request.
Q_DECL_DEPRECATED void	setMetadataUrlFormat (const QString &metaUrlFormat)
	Sets the metadata format of the layer used by QGIS Server in GetCapabilities request.
Q_DECL_DEPRECATED void	setMetadataUrlType (const QString &metaUrlType)
	Set the metadata type of the layer used by QGIS Server in GetCapabilities request MetadataUrlType indicates the standard to which the metadata complies.
void	setName (const QString &name)
	Set the display name of the layer.
virtual void	setOpacity (double opacity)
	Sets the opacity for the layer, where opacity is a value between 0 (totally transparent) and 1.0 (fully opaque).
void	setOriginalXmlProperties (const QString &originalXmlProperties)
	Sets the original XML properties for the layer to originalXmlProperties.
void	setRenderer3D (QgsAbstract3DRenderer *renderer)
	Sets 3D renderer for the layer.
void	setShortName (const QString &shortName)
	Sets the short name of the layer used by QGIS Server to identify the layer.
virtual void	setSubLayerVisibility (const QString &name, bool visible)
	Set the visibility of the given sublayer name.
void	setTitle (const QString &title)
	Sets the title of the layer used by QGIS Server in GetCapabilities request.
QString	shortName () const
	Returns the short name of the layer used by QGIS Server to identify the layer.
QString	source () const
	Returns the source for the layer.
QgsMapLayerStyleManager *	styleManager () const
	Gets access to the layer's style manager.
virtual QString	styleURI () const
	Retrieve the style URI for this layer (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
virtual QStringList	subLayers () const
	Returns the sublayers of this layer.
virtual QDateTime	timestamp () const
	Time stamp of data source in the moment when data/metadata were loaded by provider.
QString	title () const
	Returns the title of the layer used by QGIS Server in GetCapabilities request.
QgsCoordinateTransformContext	transformContext () const
	Returns the layer data provider coordinate transform context or a default transform context if the layer does not have a valid data provider.
Qgis::LayerType	type () const
	Returns the type of the layer.
QUndoStack *	undoStack ()
	Returns pointer to layer's undo stack.
QUndoStack *	undoStackStyles ()
	Returns pointer to layer's style undo stack.
QgsRectangle	wgs84Extent (bool forceRecalculate=false) const
	Returns the WGS84 extent (EPSG:4326) of the layer according to ReadFlag::FlagTrustLayerMetadata.
bool	writeLayerXml (QDomElement &layerElement, QDomDocument &document, const QgsReadWriteContext &context) const
	Stores state in DOM node.
virtual bool	writeStyle (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories) const
	Write just the symbology information for the layer into the document.
virtual bool	writeSymbology (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories) const =0
	Write the style for the layer into the document provided.
Public Member Functions inherited from QgsExpressionContextGenerator
virtual	~QgsExpressionContextGenerator ()=default
Public Member Functions inherited from QgsExpressionContextScopeGenerator
virtual	~QgsExpressionContextScopeGenerator ()=default
Public Member Functions inherited from QgsFeatureSink
virtual	~QgsFeatureSink ()=default
virtual bool	addFeatures (QgsFeatureIterator &iterator, QgsFeatureSink::Flags flags=QgsFeatureSink::Flags())
	Adds all features from the specified iterator to the sink.
virtual bool	flushBuffer ()
	Flushes any internal buffer which may exist in the sink, causing any buffered features to be added to the sink's destination.
virtual QString	lastError () const
	Returns the most recent error encountered by the sink, e.g.
Public Member Functions inherited from QgsFeatureSource
virtual	~QgsFeatureSource ()=default
virtual QgsFeatureIds	allFeatureIds () const
	Returns a list of all feature IDs for features present in the source.
virtual Qgis::SpatialIndexPresence	hasSpatialIndex () const
	Returns an enum value representing the presence of a valid spatial index on the source, if it can be determined.
QgsVectorLayer *	materialize (const QgsFeatureRequest &request, QgsFeedback *feedback=nullptr)
	Materializes a request (query) made against this feature source, by running it over the source and returning a new memory based vector layer containing the result.
Public Member Functions inherited from QgsAbstractProfileSource
virtual	~QgsAbstractProfileSource ()

Static Public Member Functions
static Q_DECL_DEPRECATED void	drawVertexMarker (double x, double y, QPainter &p, Qgis::VertexMarkerType type, int vertexSize)
	Draws a vertex symbol at (screen) coordinates x, y.
Static Public Member Functions inherited from QgsMapLayer
static QString	extensionPropertyType (PropertyType type)
	Returns the extension of a Property.
static QString	formatLayerName (const QString &name)
	A convenience function to capitalize and format a layer name.
static QString	generateId (const QString &layerName)
	Generates an unique identifier for this layer, the generate ID is prefixed by layerName.
static QgsDataProvider::ReadFlags	providerReadFlags (const QDomNode &layerNode, QgsMapLayer::ReadFlags layerReadFlags)
	Returns provider read flag deduced from layer read flags layerReadFlags and a dom node layerNode that describes a layer (corresponding to `‘maplayer’' tag in a DOM document project file read by QgsProject).

Static Public Attributes
static const QgsSettingsEntryEnumFlag< QgsVectorSimplifyMethod::SimplifyAlgorithm > *	settingsSimplifyAlgorithm = new QgsSettingsEntryEnumFlag<QgsVectorSimplifyMethod::SimplifyAlgorithm>( QStringLiteral( "simplifyAlgorithm" ), QgsSettingsTree::sTreeQgis, QgsVectorSimplifyMethod::SimplifyAlgorithm::Distance )
static const QgsSettingsEntryEnumFlag< QgsVectorSimplifyMethod::SimplifyHints > *	settingsSimplifyDrawingHints = new QgsSettingsEntryEnumFlag<QgsVectorSimplifyMethod::SimplifyHints>( QStringLiteral( "simplifyDrawingHints" ), QgsSettingsTree::sTreeQgis, QgsVectorSimplifyMethod::SimplifyHint::NoSimplification )
static const QgsSettingsEntryDouble *	settingsSimplifyDrawingTol = new QgsSettingsEntryDouble( QStringLiteral( "simplifyDrawingTol" ), QgsSettingsTree::sTreeQgis, Qgis::DEFAULT_MAPTOPIXEL_THRESHOLD )
static const QgsSettingsEntryBool *	settingsSimplifyLocal = new QgsSettingsEntryBool( QStringLiteral( "simplifyLocal" ), QgsSettingsTree::sTreeQgis, true )
static const QgsSettingsEntryDouble *	settingsSimplifyMaxScale = new QgsSettingsEntryDouble( QStringLiteral( "simplifyMaxScale" ), QgsSettingsTree::sTreeQgis, 1.0 )

Protected Member Functions
void	setExtent (const QgsRectangle &rect) FINAL
	Sets the extent.
void	setExtent3D (const QgsBox3D &rect) FINAL
	Sets the extent.
Protected Member Functions inherited from QgsMapLayer
void	appendError (const QgsErrorMessage &error)
	Add error message.
void	clone (QgsMapLayer *layer) const
	Copies attributes like name, short name, ... into another layer.
QString	crsHtmlMetadata () const
	Returns a HTML fragment containing the layer's CRS metadata, for use in the htmlMetadata() method.
QString	generalHtmlMetadata () const
	Returns an HTML fragment containing general metadata information, for use in the htmlMetadata() method.
Q_DECL_DEPRECATED bool	hasDependencyCycle (const QSet< QgsMapLayerDependency > &) const
	Checks whether a new set of dependencies will introduce a cycle this method is now deprecated and always return false, because circular dependencies are now correctly managed.
void	invalidateWgs84Extent ()
	Invalidates the WGS84 extent.
void	readCommonStyle (const QDomElement &layerElement, const QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories)
	Read style data common to all layer types.
void	readCustomProperties (const QDomNode &layerNode, const QString &keyStartsWith=QString())
	Read custom properties from project file.
void	readStyleManager (const QDomNode &layerNode)
	Read style manager's configuration (if any). To be called by subclasses.
void	setError (const QgsError &error)
	Sets error message.
void	setProviderType (const QString &providerType)
	Sets the providerType (provider key)
void	setValid (bool valid)
	Sets whether layer is valid or not.
void	writeCommonStyle (QDomElement &layerElement, QDomDocument &document, const QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories) const
	Write style data common to all layer types.
void	writeCustomProperties (QDomNode &layerNode, QDomDocument &doc) const
	Write custom properties to project file.
void	writeStyleManager (QDomNode &layerNode, QDomDocument &doc) const
	Write style manager's configuration (if exists). To be called by subclasses.

Properties
QString	displayExpression
QgsEditFormConfig	editFormConfig
bool	readOnly
QString	subsetString
bool	supportsEditing
Properties inherited from QgsMapLayer
int	autoRefreshInterval
QgsCoordinateReferenceSystem	crs
bool	isValid
bool	mapTipsEnabled
QString	mapTipTemplate
QgsLayerMetadata	metadata
QString	name
double	opacity
Qgis::LayerType	type

Friends
class	QgsVectorLayerEditBuffer
class	QgsVectorLayerEditBufferGroup
class	QgsVectorLayerEditPassthrough
class	QgsVectorLayerFeatureSource

Additional Inherited Members
Public Types inherited from QgsMapLayer
enum	LayerFlag { Identifiable = 1 << 0 , Removable = 1 << 1 , Searchable = 1 << 2 , Private = 1 << 3 }
	Flags for the map layer. More...
enum	PropertyType { Style = 0 , Metadata }
	Maplayer has a style and a metadata property. More...
enum	ReadFlag { FlagDontResolveLayers = 1 << 0 , FlagTrustLayerMetadata = 1 << 1 , FlagReadExtentFromXml = 1 << 2 , FlagForceReadOnly = 1 << 3 }
	Flags which control project read behavior. More...
enum	StyleCategory {   LayerConfiguration = 1 << 0 , Symbology = 1 << 1 , Symbology3D = 1 << 2 , Labeling = 1 << 3 ,   Fields = 1 << 4 , Forms = 1 << 5 , Actions = 1 << 6 , MapTips = 1 << 7 ,   Diagrams = 1 << 8 , AttributeTable = 1 << 9 , Rendering = 1 << 10 , CustomProperties = 1 << 11 ,   GeometryOptions = 1 << 12 , Relations = 1 << 13 , Temporal = 1 << 14 , Legend = 1 << 15 ,   Elevation = 1 << 16 , Notes = 1 << 17 , AllStyleCategories }
	Categories of style to distinguish appropriate sections for import/export. More...
Public Types inherited from QgsFeatureSink
enum	Flag { FastInsert = 1 << 1 , RollBackOnErrors = 1 << 2 }
	Flags controlling how features are added to a sink. More...
enum	SinkFlag { RegeneratePrimaryKey = 1 << 1 }
	Flags that can be set on a QgsFeatureSink. More...
Protected Attributes inherited from QgsMapLayer
QString	mAbstract
	Description of the layer.
QString	mAttribution
	Attribution of the layer.
QString	mAttributionUrl
int	mBlockStyleChangedSignal = 0
	If non-zero, the styleChanged signal should not be emitted.
QString	mDataSource
	Data source description string, varies by layer type.
QString	mDataUrl
	DataUrl of the layer.
QString	mDataUrlFormat
QSet< QgsMapLayerDependency >	mDependencies
	List of layers that may modify this layer on modification.
QgsError	mError
	Error.
bool	mIsRefreshOnNofifyEnabled = false
QString	mKeywordList
QString	mLayerName
	Name of the layer - used for display.
double	mLayerOpacity = 1.0
	Layer opacity.
QString	mLegendUrl
	WMS legend.
QString	mLegendUrlFormat
std::unique_ptr< QgsDataProvider >	mPreloadedProvider
	Optionally used when loading a project, it is released when the layer is effectively created.
QString	mProviderKey
	Data provider key (name of the data provider)
QgsMapLayer::ReadFlags	mReadFlags = QgsMapLayer::ReadFlags()
	Read flags. It's up to the subclass to respect these when restoring state from XML.
QString	mRefreshOnNofifyMessage
QString	mShortName
bool	mShouldValidateCrs = true
	true if the layer's CRS should be validated and invalid CRSes are not permitted.
QString	mTitle
bool	mValid = false
	Indicates if the layer is valid and can be drawn.

Detailed Description

Represents a vector layer which manages a vector based data sets.

The QgsVectorLayer is instantiated by specifying the name of a data provider, such as postgres or wfs, and url defining the specific data set to connect to. The vector layer constructor in turn instantiates a QgsVectorDataProvider subclass corresponding to the provider type, and passes it the url. The data provider connects to the data source.

The QgsVectorLayer provides a common interface to the different data types. It also manages editing transactions by buffering layer edits until they are written to the underlying QgsVectorDataProvider. Before edits can be made a call to startEditing() is required. Any edits made to a QgsVectorLayer are then held in memory only, and are not written to the underlying QgsVectorDataProvider until a call to commitChanges() is made. Buffered edits can be rolled back and discarded without altering the underlying provider by calling rollBack().

Sample usage of the QgsVectorLayer class:

uri = "point?crs=epsg:4326&field=id:integer"
scratchLayer = QgsVectorLayer(uri, "Scratch point layer",  "memory")

The main data providers supported by QGIS are listed below.

Vector data providers

Memory data providerType (memory)

The memory data provider is used to construct in memory data, for example scratch data or data generated from spatial operations such as contouring. There is no inherent persistent storage of the data. The data source uri is constructed. The url specifies the geometry type ("point", "linestring", "polygon", "multipoint","multilinestring","multipolygon"), optionally followed by url parameters as follows:

• crs=definition Defines the coordinate reference system to use for the layer. definition is any string accepted by QgsCoordinateReferenceSystem::createFromString()
• index=yes Specifies that the layer will be constructed with a spatial index
• field=name:type(length,precision) Defines an attribute of the layer. Multiple field parameters can be added to the data provider definition. type is one of "integer", "double", "string".

An example url is "Point?crs=epsg:4326&field=id:integer&field=name:string(20)&index=yes"

Since QGIS 3.4 when closing a project, the application shows a warning about potential data loss if there are any non-empty memory layers present. If your memory layer should not trigger such warning, it is possible to suppress that by setting the following custom variable:

layer.setCustomProperty("skipMemoryLayersCheck", 1)

OGR data provider (ogr)

Accesses data using the OGR drivers (https://gdal.org/drivers/vector/index.html). The url is the OGR connection string. A wide variety of data formats can be accessed using this driver, including file based formats used by many GIS systems, database formats, and web services. Some of these formats are also supported by custom data providers listed below.

SpatiaLite data provider (spatialite)

Access data in a SpatiaLite database. The url defines the connection parameters, table, geometry column, and other attributes. The url can be constructed using the QgsDataSourceUri class.

PostgreSQL data provider (postgres)

Connects to a PostgreSQL database. The url defines the connection parameters, table, geometry column, and other attributes. The url can be constructed using the QgsDataSourceUri class.

Microsoft SQL server data provider (mssql)

Connects to a Microsoft SQL server database. The url defines the connection parameters, table, geometry column, and other attributes. The url can be constructed using the QgsDataSourceUri class.

WFS (web feature service) data provider (wfs)

Used to access data provided by a web feature service.

The url can be a HTTP url to a WFS server (legacy, e.g. http://foobar/wfs?TYPENAME=xxx&SRSNAME=yyy[&FILTER=zzz]), or a URI constructed using the QgsDataSourceUri class with the following parameters (note that parameter keys are case sensitive):

• url=string (mandatory): HTTP url to a WFS server endpoint. e.g http://foobar/wfs
• typename=string (mandatory): WFS typename
• srsname=string (recommended): SRS like 'EPSG:XXXX'
• username=string
• password=string
• authcfg=string
• version=auto/1.0.0/1.1.0/2.0.0
• sql=string: full SELECT SQL statement with optional WHERE, ORDER BY and possibly with JOIN if supported on server
• filter=string: QGIS expression or OGC/FES filter
• restrictToRequestBBOX=1: to download only features in the view extent (or more generally in the bounding box of the feature iterator)
• pageSize=number: number of features to retrieve in a single request (WFS 2)
• maxNumFeatures=number: maximum number of features to retrieve (possibly across several multiple paging requests)
• IgnoreAxisOrientation=1: to ignore EPSG axis order for WFS 1.1 or 2.0
• InvertAxisOrientation=1: to invert axis order
• hideDownloadProgressDialog=1: to hide the download progress dialog

The ‘filter’ key value can either be a QGIS expression or an OGC XML filter. If the value is set to a QGIS expression the driver will turn it into OGC XML filter before passing it to the WFS server. Beware the QGIS expression filter only supports” =, !=, <, >, <=, >=, AND, OR, NOT, LIKE, IS NULL” attribute operators, “BBOX, Disjoint, Intersects, Touches, Crosses, Contains, Overlaps, Within” spatial binary operators and the QGIS local “geomFromWKT, geomFromGML” geometry constructor functions.

OGC API Features data provider (oapif)

Used to access data provided by a OGC API - Features server.

The URI should be constructed using the QgsDataSourceUri class with the following parameters:

• url=string (mandatory): HTTP url to a OGC API - Features landing page.
• typename=string (mandatory): Collection id
• username=string
• password=string
• authcfg=string
• filter=string: QGIS expression (only datetime filtering is forwarded to the server)
• restrictToRequestBBOX=1: to download only features in the view extent (or more generally in the bounding box of the feature iterator)
• pageSize=number: number of features to retrieve in a single request
• maxNumFeatures=number: maximum number of features to retrieve (possibly across several multiple paging requests)
• hideDownloadProgressDialog=1: to hide the download progress dialog.

Also note:

• You can use various functions available in the QGIS Expression list, however the function must exist server side and have the same name and arguments to work.
• Use the special $geometry parameter to provide the layer geometry column as input into the spatial binary operators e.g intersects($geometry, geomFromWKT('POINT (5 6)'))

Delimited text file data provider (delimitedtext)

Accesses data in a delimited text file, for example CSV files generated by spreadsheets. The contents of the file are split into columns based on specified delimiter characters. Each record may be represented spatially either by an X and Y coordinate column, or by a WKT (well known text) formatted columns.

The url defines the filename, the formatting options (how the text in the file is divided into data fields, and which fields contain the X,Y coordinates or WKT text definition. The options are specified as url query items.

At its simplest the url can just be the filename, in which case it will be loaded as a CSV formatted file.

The url may include the following items:

• encoding=UTF-8

  Defines the character encoding in the file. The default is UTF-8. To use the default encoding for the operating system use "System".

• type=(csv|regexp|whitespace|plain)

  Defines the algorithm used to split records into columns. Records are defined by new lines, except for csv format files for which quoted fields may span multiple records. The default type is csv.

• "csv" splits the file based on three sets of characters: delimiter characters, quote characters, and escape characters. Delimiter characters mark the end of a field. Quote characters enclose a field which can contain delimiter characters, and newlines. Escape characters cause the following character to be treated literally (including delimiter, quote, and newline characters). Escape and quote characters must be different from delimiter characters. Escape characters that are also quote characters are treated specially - they can only escape themselves within quotes. Elsewhere they are treated as quote characters. The defaults for delimiter, quote, and escape are ',', '"', '"'.
• "regexp" splits each record using a regular expression (see QRegularExpression documentation for details).
• "whitespace" splits each record based on whitespace (on or more whitespace characters. Leading whitespace in the record is ignored.
• "plain" is provided for backwards compatibility. It is equivalent to CSV except that the default quote characters are single and double quotes, and there is no escape characters.

• delimiter=characters

  Defines the delimiter characters used for csv and plain type files, or the regular expression for regexp type files. It is a literal string of characters except that "\t" may be used to represent a tab character.

• quote=characters

  Defines the characters that are used as quote characters for csv and plain type files.

• escape=characters

  Defines the characters used to escape delimiter, quote, and newline characters.

• skipLines=n

  Defines the number of lines to ignore at the beginning of the file (default 0)

• useHeader=(yes|no)

  Defines whether the first record in the file (after skipped lines) contains column names (default yes)

• trimFields=(yes|no)

  If yes then leading and trailing whitespace will be removed from fields

• skipEmptyFields=(yes|no)

  If yes then empty fields will be discarded (equivalent to concatenating consecutive delimiters)

• maxFields=#

  Specifies the maximum number of fields to load for each record. Additional fields will be discarded. Default is 0 - load all fields.

• decimalPoint=c

  Defines a character that is used as a decimal point in the numeric columns The default is '.'.

• xField=column yField=column

  Defines the name of the columns holding the x and y coordinates for XY point geometries. If the useHeader is no (ie there are no column names), then this is the column number (with the first column as 1).

• xyDms=(yes|no)

  If yes then the X and Y coordinates are interpreted as degrees/minutes/seconds format (fairly permissively), or degree/minutes format.

• wktField=column

  Defines the name of the columns holding the WKT geometry definition for WKT geometries. If the useHeader is no (ie there are no column names), then this is the column number (with the first column as 1).

• geomType=(point|line|polygon|none)

  Defines the geometry type for WKT type geometries. QGIS will only display one type of geometry for the layer - any others will be ignored when the file is loaded. By default the provider uses the type of the first geometry in the file. Use geomType to override this type.

  geomType can also be set to none, in which case the layer is loaded without geometries.

• subset=expression

  Defines an expression that will identify a subset of records to display

• crs=crsstring

  Defines the coordinate reference system used for the layer. This can be any string accepted by QgsCoordinateReferenceSystem::createFromString()

• subsetIndex=(yes|no)

  Determines whether the provider generates an index to improve the efficiency of subsets. The default is yes

• spatialIndex=(yes|no)

  Determines whether the provider generates a spatial index. The default is no.

• watchFile=(yes|no)

  Defines whether the file will be monitored for changes. The default is to monitor for changes.

• quiet

  Errors encountered loading the file will not be reported in a user dialog if quiet is included (They will still be shown in the output log).

GPX data provider (gpx)

Provider reads tracks, routes, and waypoints from a GPX file. The url defines the name of the file, and the type of data to retrieve from it ("track", "route", or "waypoint").

An example url is "/home/user/data/holiday.gpx?type=route"

Grass data provider (grass)

Provider to display vector data in a GRASS GIS layer.

See also

QgsVectorLayerUtils()

Definition at line 399 of file qgsvectorlayer.h.

Constructor & Destructor Documentation

QgsVectorLayer() [1/2]

QgsVectorLayer::QgsVectorLayer ( const QString &  path = QString(), const QString &  baseName = QString(), const QString &  providerLib = "ogr", const QgsVectorLayer::LayerOptions &  options = QgsVectorLayer::LayerOptions()  )

explicit

Constructor - creates a vector layer.

The QgsVectorLayer is constructed by instantiating a data provider. The provider interprets the supplied path (url) of the data source to connect to and access the data.

Parameters

path	The path or url of the parameter. Typically this encodes parameters used by the data provider as url query items.
baseName	The name used to represent the layer in the legend
providerLib	The name of the data provider, e.g., "memory", "postgres"
options	layer load options

Definition at line 162 of file qgsvectorlayer.cpp.

~QgsVectorLayer()

QgsVectorLayer::~QgsVectorLayer ( )

override

Definition at line 249 of file qgsvectorlayer.cpp.

QgsVectorLayer() [2/2]

QgsVectorLayer::QgsVectorLayer ( const QgsVectorLayer &  rhs )

delete

QgsVectorLayer cannot be copied.

Member Function Documentation

accept

bool QgsVectorLayer::accept ( QgsStyleEntityVisitorInterface *  visitor ) const

overrideslot

Definition at line 1852 of file qgsvectorlayer.cpp.

actions() [1/2]

QgsActionManager * QgsVectorLayer::actions ( )

inline

Returns all layer actions defined on this layer.

The pointer which is returned directly points to the actions object which is used by the layer, so any changes are immediately applied.

Definition at line 775 of file qgsvectorlayer.h.

actions() [2/2]

const QgsActionManager * QgsVectorLayer::actions ( ) const

inline

Returns all layer actions defined on this layer.

The pointer which is returned is const.

Definition at line 782 of file qgsvectorlayer.h.

addAttribute()

bool QgsVectorLayer::addAttribute

(

const QgsField &

field

)

Add an attribute field (but does not commit it) returns true if the field was added.

Note

Calls to addAttribute() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 3441 of file qgsvectorlayer.cpp.

addExpressionField()

int QgsVectorLayer::addExpressionField	(	const QString &	exp,
		const QgsField &	fld
	)

Add a new field which is calculated by the expression specified.

Parameters

exp	The expression which calculates the field
fld	The field to calculate

Returns

The index of the new field

Definition at line 4355 of file qgsvectorlayer.cpp.

addFeature()

bool QgsVectorLayer::addFeature ( QgsFeature &  feature, QgsFeatureSink::Flags  flags = QgsFeatureSink::Flags()  )

virtual

Adds a single feature to the sink.

Feature addition behavior is controlled by the specified flags.

See also

addFeatures()

Returns

true in case of success and false in case of failure

Reimplemented from QgsFeatureSink.

Definition at line 1327 of file qgsvectorlayer.cpp.

addFeatureRendererGenerator()

void QgsVectorLayer::addFeatureRendererGenerator

(

QgsFeatureRendererGenerator *

generator

)

Adds a new feature renderer generator to the layer.

Ownership of generator is transferred to the layer.

See also

removeFeatureRendererGenerator()

featureRendererGenerators()

Since

QGIS 3.18

Definition at line 4235 of file qgsvectorlayer.cpp.

addFeatures()

bool QgsVectorLayer::addFeatures ( QgsFeatureList &  features, QgsFeatureSink::Flags  flags = QgsFeatureSink::Flags()  )

virtual

Adds a list of features to the sink.

Feature addition behavior is controlled by the specified flags.

See also

addFeature()

Returns

true in case of success and false in case of failure

Implements QgsFeatureSink.

Definition at line 4024 of file qgsvectorlayer.cpp.

addJoin()

bool QgsVectorLayer::addJoin

(

const QgsVectorLayerJoinInfo &

joinInfo

)

Joins another vector layer to this layer.

Parameters

joinInfo

join object containing join layer id, target and source field

Note

since 2.6 returns bool indicating whether the join can be added

Definition at line 4334 of file qgsvectorlayer.cpp.

addPart() [1/3]

Qgis::GeometryOperationResult QgsVectorLayer::addPart

(

const QgsPointSequence &

ring

)

Adds a new part polygon to a multipart feature.

Returns

Qgis::GeometryOperationResult

• Success
• LayerNotEditable
• SelectionIsEmpty
• SelectionIsGreaterThanOne
• AddPartSelectedGeometryNotFound
• AddPartNotMultiGeometry
• InvalidBaseGeometry
• InvalidInputGeometryType

Note

available in Python bindings as addPartV2

Calls to addPart() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1631 of file qgsvectorlayer.cpp.

addPart() [2/3]

Qgis::GeometryOperationResult QgsVectorLayer::addPart

(

const QList< QgsPointXY > &

ring

)

Adds a new part polygon to a multipart feature.

Returns

Qgis::GeometryOperationResult

• Success
• LayerNotEditable
• SelectionIsEmpty
• SelectionIsGreaterThanOne
• AddPartSelectedGeometryNotFound
• AddPartNotMultiGeometry
• InvalidBaseGeometry
• InvalidInputGeometryType

Note

Calls to addPart() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Deprecated:

since QGIS 3.12 - will be removed in QGIS 4.0. Use the variant which accepts QgsPoint objects instead of QgsPointXY.

Definition at line 1609 of file qgsvectorlayer.cpp.

addPart() [3/3]

Qgis::GeometryOperationResult QgsVectorLayer::addPart

(

QgsCurve *

ring

)

Note

available in Python as addCurvedPart

Calls to addPart() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1659 of file qgsvectorlayer.cpp.

addRing() [1/3]

Qgis::GeometryOperationResult QgsVectorLayer::addRing	(	const QgsPointSequence &	ring,
		QgsFeatureId *	featureId = nullptr
	)

Adds a ring to polygon/multipolygon features.

Parameters

ring	ring to add
featureId	if specified, feature ID for feature ring was added to will be stored in this parameter

Returns

Qgis::GeometryOperationResult

• Success
• LayerNotEditable
• AddRingNotInExistingFeature
• InvalidInputGeometryType
• AddRingNotClosed
• AddRingNotValid
• AddRingCrossesExistingRings

Note

Calls to addRing() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1544 of file qgsvectorlayer.cpp.

addRing() [2/3]

Qgis::GeometryOperationResult QgsVectorLayer::addRing	(	const QVector< QgsPointXY > &	ring,
		QgsFeatureId *	featureId = nullptr
	)

Adds a ring to polygon/multipolygon features.

Parameters

ring	ring to add
featureId	if specified, feature ID for feature ring was added to will be stored in this parameter

Returns

Qgis::GeometryOperationResult

• Success
• LayerNotEditable
• AddRingNotInExistingFeature
• InvalidInputGeometryType
• AddRingNotClosed
• AddRingNotValid
• AddRingCrossesExistingRings

Note

Calls to addRing() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Deprecated:

since QGIS 3.12 - will be removed in QGIS 4.0. Use the variant which accepts QgsPoint objects instead of QgsPointXY.

Definition at line 1537 of file qgsvectorlayer.cpp.

addRing() [3/3]

Qgis::GeometryOperationResult QgsVectorLayer::addRing	(	QgsCurve *	ring,
		QgsFeatureId *	featureId = nullptr
	)

Adds a ring to polygon/multipolygon features (takes ownership)

Parameters

ring	ring to add
featureId	if specified, feature ID for feature ring was added to will be stored in this parameter

Returns

Qgis::GeometryOperationResult

• Success
• LayerNotEditable
• AddRingNotInExistingFeature
• InvalidInputGeometryType
• AddRingNotClosed
• AddRingNotValid
• AddRingCrossesExistingRings

Note

available in Python as addCurvedRing

Calls to addRing() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1569 of file qgsvectorlayer.cpp.

addTopologicalPoints() [1/4]

int QgsVectorLayer::addTopologicalPoints

(

const QgsGeometry &

geom

)

Adds topological points for every vertex of the geometry.

Parameters

geom	the geometry where each vertex is added to segments of other features

Returns

-1 in case of layer error (invalid or non editable)

0 in case of success

1 in case of geometry error (non spatial or null geometry)

2 in case no vertices needed to be added

Note

geom is not going to be modified by the function

Calls to addTopologicalPoints() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1749 of file qgsvectorlayer.cpp.

addTopologicalPoints() [2/4]

int QgsVectorLayer::addTopologicalPoints

(

const QgsPoint &

p

)

Adds a vertex to segments which intersect point p but don't already have a vertex there.

If a feature already has a vertex at position p, no additional vertex is inserted. This method is useful for topological editing.

Parameters

p	position of the vertex

Returns

-1 in case of layer error (invalid or non editable)

0 in case of success

1 in case of geometry error (non spatial or null geometry)

2 in case no vertices needed to be added

Note

Calls to addTopologicalPoints() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Since

QGIS 3.10

Definition at line 1767 of file qgsvectorlayer.cpp.

addTopologicalPoints() [3/4]

int QgsVectorLayer::addTopologicalPoints

(

const QgsPointSequence &

ps

)

Adds a vertex to segments which intersect any of the points p but don't already have a vertex there.

If a feature already has a vertex at position p, no additional vertex is inserted. This method is useful for topological editing.

Parameters

ps	point sequence of the vertices

Returns

-1 in case of layer error (invalid or non editable)

0 in case of success

1 in case of geometry error (non spatial or null geometry)

2 in case no vertices needed to be added

Note

Calls to addTopologicalPoints() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Since

QGIS 3.16

Definition at line 1778 of file qgsvectorlayer.cpp.

addTopologicalPoints() [4/4]

int QgsVectorLayer::addTopologicalPoints

(

const QgsPointXY &

p

)

Adds a vertex to segments which intersect point p but don't already have a vertex there.

If a feature already has a vertex at position p, no additional vertex is inserted. This method is useful for topological editing.

Parameters

p	position of the vertex

Returns

-1 in case of layer error (invalid or non editable)

0 in case of success

1 in case of geometry error (non spatial or null geometry)

2 in case no vertices needed to be added

Note

Calls to addTopologicalPoints() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Deprecated:

since QGIS 3.12 - will be removed in QGIS 4.0. Use the variant which accepts QgsPoint objects instead of QgsPointXY.

Definition at line 1760 of file qgsvectorlayer.cpp.

afterCommitChanges

void QgsVectorLayer::afterCommitChanges ( )

signal

Emitted after changes are committed to the data provider.

Since

QGIS 3.16

afterRollBack

void QgsVectorLayer::afterRollBack ( )

signal

Emitted after changes are rolled back.

Since

QGIS 3.4

aggregate()

QVariant QgsVectorLayer::aggregate	(	Qgis::Aggregate	aggregate,
		const QString &	fieldOrExpression,
		const QgsAggregateCalculator::AggregateParameters &	parameters = QgsAggregateCalculator::AggregateParameters(),
		QgsExpressionContext *	context = nullptr,
		bool *	ok = nullptr,
		QgsFeatureIds *	fids = nullptr,
		QgsFeedback *	feedback = nullptr,
		QString *	error = nullptr
	)		const

Calculates an aggregated value from the layer's features.

Currently any filtering expression provided will override filters in the FeatureRequest.

Parameters

aggregate	aggregate to calculate
fieldOrExpression	source field or expression to use as basis for aggregated values.
parameters	parameters controlling aggregate calculation
context	expression context for expressions and filters
ok	if specified, will be set to true if aggregate calculation was successful
fids	list of fids to filter, otherwise will use all fids
feedback	optional feedback argument for early cancellation (since QGIS 3.22)
error	optional storage for error messages (not available in Python bindings)

Returns

calculated aggregate value

Definition at line 5012 of file qgsvectorlayer.cpp.

allowCommit()

bool QgsVectorLayer::allowCommit

(

)

const

Controls, if the layer is allowed to commit changes.

If this is set to false it will not be possible to commit changes on this layer. This can be used to define checks on a layer that need to be pass before the layer can be saved. If you use this API, make sure that:

• the user is visibly informed that his changes were not saved and what he needs to do in order to be able to save the changes.
• to set the property back to true, once the user has fixed his data.

When calling

See also

commitChanges() this flag is checked just after the

beforeCommitChanges() signal is emitted, so it's possible to adjust it from there.

Note

Not available in Python bindings

Since

QGIS 3.4

Definition at line 6287 of file qgsvectorlayer.cpp.

allowCommitChanged

void QgsVectorLayer::allowCommitChanged ( )

signal

Emitted whenever the allowCommitChanged() property of this layer changes.

Since

QGIS 3.4

attributeAdded

void QgsVectorLayer::attributeAdded ( int  idx )

signal

Will be emitted, when a new attribute has been added to this vector layer.

Applies only to types QgsFields::OriginEdit, QgsFields::OriginProvider and QgsFields::OriginExpression

Parameters

idx	The index of the new attribute

See also

updatedFields()

attributeAlias()

QString QgsVectorLayer::attributeAlias

(

int

index

)

const

Returns the alias of an attribute name or a null string if there is no alias.

See also

{attributeDisplayName( int attributeIndex )} which returns the field name if no alias is defined.

Definition at line 3525 of file qgsvectorlayer.cpp.

attributeAliases()

QgsStringMap QgsVectorLayer::attributeAliases

(

)

const

Returns a map of field name to attribute alias.

Definition at line 3545 of file qgsvectorlayer.cpp.

attributeDeleted

void QgsVectorLayer::attributeDeleted ( int  idx )

signal

Will be emitted, when an attribute has been deleted from this vector layer.

Applies only to types QgsFields::OriginEdit, QgsFields::OriginProvider and QgsFields::OriginExpression

Parameters

idx	The index of the deleted attribute

See also

updatedFields()

attributeDisplayName()

QString QgsVectorLayer::attributeDisplayName

(

int

index

)

const

Convenience function that returns the attribute alias if defined or the field name else.

Definition at line 3535 of file qgsvectorlayer.cpp.

attributeList()

QgsAttributeList QgsVectorLayer::attributeList ( ) const

inline

Returns list of attribute indexes.

i.e. a list from 0 ... fieldCount()

Definition at line 1668 of file qgsvectorlayer.h.

attributeTableConfig()

QgsAttributeTableConfig QgsVectorLayer::attributeTableConfig

(

)

const

Returns the attribute table configuration object.

This defines the appearance of the attribute table.

Definition at line 5655 of file qgsvectorlayer.cpp.

attributeValueChanged

void QgsVectorLayer::attributeValueChanged ( QgsFeatureId  fid, int  idx, const QVariant &  value  )

signal

Emitted whenever an attribute value change is done in the edit buffer.

Note that at this point the attribute change is not yet saved to the provider.

Parameters

fid	The id of the changed feature
idx	The attribute index of the changed attribute
value	The new value of the attribute

auxiliaryLayer() [1/2]

QgsAuxiliaryLayer * QgsVectorLayer::auxiliaryLayer

(

)

Returns the current auxiliary layer.

Definition at line 5991 of file qgsvectorlayer.cpp.

auxiliaryLayer() [2/2]

const QgsAuxiliaryLayer * QgsVectorLayer::auxiliaryLayer

(

)

const

Returns the current const auxiliary layer.

Definition at line 5984 of file qgsvectorlayer.cpp.

beforeAddingExpressionField

void QgsVectorLayer::beforeAddingExpressionField ( const QString &  fieldName )

signal

Will be emitted, when an expression field is going to be added to this vector layer.

Applies only to types QgsFields::OriginExpression

Parameters

fieldName

The name of the attribute to be added

beforeCommitChanges

void QgsVectorLayer::beforeCommitChanges ( bool  stopEditing )

signal

Emitted before changes are committed to the data provider.

The stopEditing flag specifies if the editing mode shall be left after this commit.

beforeEditingStarted

void QgsVectorLayer::beforeEditingStarted ( )

signal

Emitted before editing on this layer is started.

beforeModifiedCheck

void QgsVectorLayer::beforeModifiedCheck ( ) const

signal

Emitted when the layer is checked for modifications. Use for last-minute additions.

beforeRemovingExpressionField

void QgsVectorLayer::beforeRemovingExpressionField ( int  idx )

signal

Will be emitted, when an expression field is going to be deleted from this vector layer.

Applies only to types QgsFields::OriginExpression

Parameters

idx	The index of the attribute to be deleted

beforeRollBack

void QgsVectorLayer::beforeRollBack ( )

signal

Emitted before changes are rolled back.

beginEditCommand()

void QgsVectorLayer::beginEditCommand

(

const QString &

text

)

Create edit command for undo/redo operations.

Parameters

text	text which is to be displayed in undo window

Definition at line 4270 of file qgsvectorlayer.cpp.

boundingBoxOfSelected()

QgsRectangle QgsVectorLayer::boundingBoxOfSelected

(

)

const

Returns the bounding box of the selected features. If there is no selection, QgsRectangle(0,0,0,0) is returned.

Definition at line 829 of file qgsvectorlayer.cpp.

capabilitiesString()

QString QgsVectorLayer::capabilitiesString

(

)

const

Capabilities for this layer, comma separated and translated.

Definition at line 405 of file qgsvectorlayer.cpp.

changeAttributeValue()

bool QgsVectorLayer::changeAttributeValue	(	QgsFeatureId	fid,
		int	field,
		const QVariant &	newValue,
		const QVariant &	oldValue = QVariant(),
		bool	skipDefaultValues = false
	)

Changes an attribute value for a feature (but does not immediately commit the changes).

The fid argument specifies the ID of the feature to be changed.

The field argument must specify a valid field index for the layer (where an index of 0 corresponds to the first field).

The new value to be assigned to the field is given by newValue.

If a valid QVariant is specified for oldValue, it will be used as the field value in the case of an undo operation corresponding to this attribute value change. If an invalid QVariant is used (the default behavior), then the feature's current value will be automatically retrieved and used. Note that this involves a feature request to the underlying data provider, so it is more efficient to explicitly pass an oldValue if it is already available.

If skipDefaultValues is set to true, default field values will not be updated. This can be used to override default field value expressions.

Returns

true if the feature's attribute was successfully changed.

Note

Calls to changeAttributeValue() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

See also

startEditing()

commitChanges()

changeGeometry()

updateFeature()

Definition at line 3345 of file qgsvectorlayer.cpp.

changeAttributeValues()

bool QgsVectorLayer::changeAttributeValues	(	QgsFeatureId	fid,
		const QgsAttributeMap &	newValues,
		const QgsAttributeMap &	oldValues = QgsAttributeMap(),
		bool	skipDefaultValues = false
	)

Changes attributes' values for a feature (but does not immediately commit the changes).

The fid argument specifies the ID of the feature to be changed.

The new values to be assigned to the fields are given by newValues.

If a valid QVariant is specified for a field in oldValues, it will be used as the field value in the case of an undo operation corresponding to this attribute value change. If an invalid QVariant is used (the default behavior), then the feature's current value will be automatically retrieved and used. Note that this involves a feature request to the underlying data provider, so it is more efficient to explicitly pass an oldValue if it is already available.

If skipDefaultValues is set to true, default field values will not be updated. This can be used to override default field value expressions.

Returns

true if feature's attributes was successfully changed.

Note

Calls to changeAttributeValues() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

See also

startEditing()

commitChanges()

changeGeometry()

updateFeature()

changeAttributeValue()

Definition at line 3378 of file qgsvectorlayer.cpp.

changeGeometry()

bool QgsVectorLayer::changeGeometry	(	QgsFeatureId	fid,
		QgsGeometry &	geometry,
		bool	skipDefaultValue = false
	)

Changes a feature's geometry within the layer's edit buffer (but does not immediately commit the changes).

The fid argument specifies the ID of the feature to be changed.

If skipDefaultValue is set to true, default field values will not be updated. This can be used to override default field value expressions.

Returns

true if the feature's geometry was successfully changed.

Note

Calls to changeGeometry() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

See also

startEditing()

commitChanges()

changeAttributeValue()

updateFeature()

Definition at line 3319 of file qgsvectorlayer.cpp.

clone()

QgsVectorLayer * QgsVectorLayer::clone ( ) const

overridevirtual

Returns a new instance equivalent to this one.

A new provider is created for the same data source and renderers for features and diagrams are cloned too. Moreover, each attributes (transparency, extent, selected features and so on) are identical.

Returns

a new layer instance

Implements QgsMapLayer.

Definition at line 275 of file qgsvectorlayer.cpp.

commitChanges()

bool QgsVectorLayer::commitChanges

(

bool

stopEditing = true

)

Attempts to commit to the underlying data provider any buffered changes made since the last to call to startEditing().

Returns the result of the attempt. If a commit fails (i.e. false is returned), the in-memory changes are left untouched and are not discarded. This allows editing to continue if the commit failed on e.g. a disallowed value in a Postgres database - the user can re-edit and try again.

The commits occur in distinct stages, (add attributes, add features, change attribute values, change geometries, delete features, delete attributes) so if a stage fails, it can be difficult to roll back cleanly. Therefore any error message returned by commitErrors() also includes which stage failed so that the user has some chance of repairing the damage cleanly.

By setting stopEditing to false, the layer will stay in editing mode. Otherwise the layer editing mode will be disabled if the commit is successful.

See also

startEditing()

commitErrors()

rollBack()

Definition at line 3836 of file qgsvectorlayer.cpp.

commitErrors()

QStringList QgsVectorLayer::commitErrors

(

)

const

Returns a list containing any error messages generated when attempting to commit changes to the layer.

See also

commitChanges()

Definition at line 3912 of file qgsvectorlayer.cpp.

committedAttributesAdded

void QgsVectorLayer::committedAttributesAdded ( const QString &  layerId, const QList< QgsField > &  addedAttributes  )

signal

Emitted when attributes are added to the provider if not in transaction mode.

committedAttributesDeleted

void QgsVectorLayer::committedAttributesDeleted ( const QString &  layerId, const QgsAttributeList &  deletedAttributes  )

signal

Emitted when attributes are deleted from the provider if not in transaction mode.

committedAttributeValuesChanges

void QgsVectorLayer::committedAttributeValuesChanges ( const QString &  layerId, const QgsChangedAttributesMap &  changedAttributesValues  )

signal

Emitted when attribute value changes are saved to the provider if not in transaction mode.

committedFeaturesAdded

void QgsVectorLayer::committedFeaturesAdded ( const QString &  layerId, const QgsFeatureList &  addedFeatures  )

signal

Emitted when features are added to the provider if not in transaction mode.

committedFeaturesRemoved

void QgsVectorLayer::committedFeaturesRemoved ( const QString &  layerId, const QgsFeatureIds &  deletedFeatureIds  )

signal

Emitted when features are deleted from the provider if not in transaction mode.

committedGeometriesChanges

void QgsVectorLayer::committedGeometriesChanges ( const QString &  layerId, const QgsGeometryMap &  changedGeometries  )

signal

Emitted when geometry changes are saved to the provider if not in transaction mode.

conditionalStyles()

QgsConditionalLayerStyles * QgsVectorLayer::conditionalStyles

(

)

const

Returns the conditional styles that are set for this layer.

Style information is used to render conditional formatting in the attribute table.

Returns

Return a QgsConditionalLayerStyles object holding the conditional attribute style information. Style information is generic and can be used for anything.

Definition at line 1297 of file qgsvectorlayer.cpp.

constraintDescription()

QString QgsVectorLayer::constraintDescription

(

int

index

)

const

Returns the descriptive name for the constraint expression for a specified field index.

See also

fieldConstraints()

constraintExpression()

setConstraintExpression()

Definition at line 6175 of file qgsvectorlayer.cpp.

constraintExpression()

QString QgsVectorLayer::constraintExpression

(

int

index

)

const

Returns the constraint expression for for a specified field index, if set.

See also

fieldConstraints()

constraintDescription()

setConstraintExpression()

Definition at line 6165 of file qgsvectorlayer.cpp.

countSymbolFeatures()

QgsVectorLayerFeatureCounter * QgsVectorLayer::countSymbolFeatures

(

bool

storeSymbolFids = false

)

Count features for symbols.

The method will return the feature counter task. You will need to connect to the symbolFeatureCountMapChanged() signal to be notified when the freshly updated feature counts are ready.

Parameters

storeSymbolFids

If true will gather the feature ids (fids) per symbol, otherwise only the count. Default false.

Note

If the count features for symbols has been already done a nullptr is returned. If you need to wait for the results, you can call waitForFinished() on the feature counter.

Definition at line 940 of file qgsvectorlayer.cpp.

createExpressionContext()

QgsExpressionContext QgsVectorLayer::createExpressionContext ( ) const

virtual

This method needs to be reimplemented in all classes which implement this interface and return an expression context.

Implements QgsExpressionContextGenerator.

Definition at line 5678 of file qgsvectorlayer.cpp.

createExpressionContextScope()

QgsExpressionContextScope * QgsVectorLayer::createExpressionContextScope ( ) const

virtual

This method needs to be reimplemented in all classes which implement this interface and return an expression context scope.

Implements QgsExpressionContextScopeGenerator.

Definition at line 5686 of file qgsvectorlayer.cpp.

createMapRenderer()

QgsMapLayerRenderer * QgsVectorLayer::createMapRenderer ( QgsRenderContext &  rendererContext )

virtual

Returns new instance of QgsMapLayerRenderer that will be used for rendering of given context.

Implements QgsMapLayer.

Definition at line 467 of file qgsvectorlayer.cpp.

createProfileGenerator()

QgsAbstractProfileGenerator * QgsVectorLayer::createProfileGenerator ( const QgsProfileRequest &  request )

overridevirtual

Given a profile request, returns a new profile generator ready for generating elevation profiles.

The caller takes ownership of the returned generator.

May return nullptr if the source cannot generate a profile at this time.

Implements QgsAbstractProfileSource.

Definition at line 784 of file qgsvectorlayer.cpp.

dataComment()

QString QgsVectorLayer::dataComment

(

)

const

Returns a description for this layer as defined in the data provider.

Definition at line 430 of file qgsvectorlayer.cpp.

dataProvider() [1/2]

const QgsVectorDataProvider * QgsVectorLayer::dataProvider ( ) const

virtual

Returns the layer's data provider in a const-correct manner, it may be nullptr.

Note

not available in Python bindings

Reimplemented from QgsMapLayer.

Definition at line 754 of file qgsvectorlayer.cpp.

dataProvider() [2/2]

QgsVectorDataProvider * QgsVectorLayer::dataProvider ( )

virtual

Returns the layer's data provider, it may be nullptr.

Reimplemented from QgsMapLayer.

Definition at line 746 of file qgsvectorlayer.cpp.

decodedSource()

QString QgsVectorLayer::decodedSource ( const QString &  source, const QString &  dataProvider, const QgsReadWriteContext &  context  ) const

virtual

Called by readLayerXML(), used by derived classes to decode provider's specific data source from project files.

Typically resolving absolute or relative paths, usernames and passwords or drivers prefixes ("HDF5:")

Parameters

source	data source to decode, typically read from layer's DOM element "datasource"
dataProvider	string identification of data provider (e.g. "ogr"), typically read from layer's DOM element
context	reading context (e.g. for conversion between relative and absolute paths)

Returns

decoded source, typically to be used as the layer's datasource

Since

QGIS 3.2

Reimplemented from QgsMapLayer.

Definition at line 2387 of file qgsvectorlayer.cpp.

defaultValue()

QVariant QgsVectorLayer::defaultValue	(	int	index,
		const QgsFeature &	feature = QgsFeature(),
		QgsExpressionContext *	context = nullptr
	)		const

Returns the calculated default value for the specified field index.

The default value may be taken from a client side default value expression (see setDefaultValueDefinition()) or taken from the underlying data provider.

Parameters

index	field index
feature	optional feature to use for default value evaluation. If passed, then properties from the feature (such as geometry) can be used when calculating the default value.
context	optional expression context to evaluate expressions again. If not specified, a default context will be created

Returns

calculated default value

See also

setDefaultValueDefinition()

Definition at line 4538 of file qgsvectorlayer.cpp.

defaultValueDefinition()

QgsDefaultValue QgsVectorLayer::defaultValueDefinition

(

int

index

)

const

Returns the definition of the expression used when calculating the default value for a field.

Parameters

index

field index

Returns

definition of the default value with the expression evaluated when calculating default values for field, or definition with an empty string if no default is set

See also

defaultValue()

setDefaultValueDefinition()

Definition at line 4604 of file qgsvectorlayer.cpp.

deleteAttribute()

bool QgsVectorLayer::deleteAttribute ( int  attr )

virtual

Deletes an attribute field (but does not commit it).

Note

Calls to deleteAttribute() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Reimplemented in QgsAuxiliaryLayer.

Definition at line 3623 of file qgsvectorlayer.cpp.

deleteAttributes()

bool QgsVectorLayer::deleteAttributes

(

const QList< int > &

attrs

)

Deletes a list of attribute fields (but does not commit it)

Parameters

attrs

the indices of the attributes to delete

Returns

true if at least one attribute has been deleted

Definition at line 3642 of file qgsvectorlayer.cpp.

deleteFeature()

bool QgsVectorLayer::deleteFeature	(	QgsFeatureId	fid,
		QgsVectorLayer::DeleteContext *	context = nullptr
	)

Deletes a feature from the layer (but does not commit it).

Parameters

fid	The feature id to delete
context	The chain of features who will be deleted for feedback and to avoid endless recursions

Note

Calls to deleteFeature() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 3735 of file qgsvectorlayer.cpp.

deleteFeatures()

bool QgsVectorLayer::deleteFeatures	(	const QgsFeatureIds &	fids,
		QgsVectorLayer::DeleteContext *	context = nullptr
	)

Deletes a set of features from the layer (but does not commit it)

Parameters

fids	The feature ids to delete
context	The chain of features who will be deleted for feedback and to avoid endless recursions

Returns

false if the layer is not in edit mode or does not support deleting in case of an active transaction depends on the provider implementation

Note

Calls to deleteFeatures() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 3752 of file qgsvectorlayer.cpp.

deleteSelectedFeatures()

bool QgsVectorLayer::deleteSelectedFeatures	(	int *	deletedCount = nullptr,
		QgsVectorLayer::DeleteContext *	context = nullptr
	)

Deletes the selected features.

Parameters

deletedCount	The number of successfully deleted features
context	The chain of features who will be deleted for feedback and to avoid endless recursions

Returns

true in case of success and false otherwise

Definition at line 1491 of file qgsvectorlayer.cpp.

deleteVertex()

Qgis::VectorEditResult QgsVectorLayer::deleteVertex	(	QgsFeatureId	featureId,
		int	vertex
	)

Deletes a vertex from a feature.

Parameters

featureId	ID of feature to remove vertex from
vertex	index of vertex to delete

Note

Calls to deleteVertex() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1475 of file qgsvectorlayer.cpp.

dependencies()

QSet< QgsMapLayerDependency > QgsVectorLayer::dependencies ( ) const

virtual

Gets the list of dependencies.

This includes data dependencies set by the user (

See also

setDataDependencies) as well as dependencies given by the provider

Returns

a set of QgsMapLayerDependency

Reimplemented from QgsMapLayer.

Definition at line 5998 of file qgsvectorlayer.cpp.

deselect [1/2]

void QgsVectorLayer::deselect ( const QgsFeatureIds &  featureIds )

slot

Deselects features by their ID.

Parameters

featureIds

The ids of the features to deselect

See also

deselect(const QgsFeatureId)

Definition at line 527 of file qgsvectorlayer.cpp.

deselect [2/2]

void QgsVectorLayer::deselect ( QgsFeatureId  featureId )

slot

Deselects feature by its ID.

Parameters

featureId

The id of the feature to deselect

See also

deselect(const QgsFeatureIds&)

Definition at line 517 of file qgsvectorlayer.cpp.

destroyEditCommand()

void QgsVectorLayer::destroyEditCommand

(

)

Destroy active command and reverts all changes in it.

Definition at line 4310 of file qgsvectorlayer.cpp.

diagramLayerSettings()

const QgsDiagramLayerSettings * QgsVectorLayer::diagramLayerSettings ( ) const

inline

Definition at line 925 of file qgsvectorlayer.h.

diagramRenderer()

const QgsDiagramRenderer * QgsVectorLayer::diagramRenderer ( ) const

inline

Definition at line 922 of file qgsvectorlayer.h.

diagramsEnabled()

bool QgsVectorLayer::diagramsEnabled

(

)

const

Returns whether the layer contains diagrams which are enabled and should be drawn.

Returns

true if layer contains enabled diagrams

Definition at line 905 of file qgsvectorlayer.cpp.

displayExpression()

QString QgsVectorLayer::displayExpression

(

)

const

Returns the preview expression, used to create a human readable preview string.

Uses QgsExpression

Returns

The expression which will be used to preview features for this layer

Definition at line 4082 of file qgsvectorlayer.cpp.

displayExpressionChanged

void QgsVectorLayer::displayExpressionChanged ( )

signal

Emitted when the display expression changes.

displayField()

QString QgsVectorLayer::displayField

(

)

const

This is a shorthand for accessing the displayExpression if it is a simple field.

If the displayExpression is more complex than a simple field, a null string will be returned.

See also

displayExpression

Definition at line 4058 of file qgsvectorlayer.cpp.

drawVertexMarker()

void QgsVectorLayer::drawVertexMarker ( double  x, double  y, QPainter &  p, Qgis::VertexMarkerType  type, int  vertexSize  )

static

Draws a vertex symbol at (screen) coordinates x, y.

(Useful to assist vertex editing.)

Deprecated:

Use the equivalent QgsSymbolLayerUtils::drawVertexMarker function instead

Definition at line 476 of file qgsvectorlayer.cpp.

editBuffer() [1/2]

Q_INVOKABLE QgsVectorLayerEditBuffer * QgsVectorLayer::editBuffer ( )

inline

Buffer with uncommitted editing operations. Only valid after editing has been turned on.

Definition at line 2011 of file qgsvectorlayer.h.

editBuffer() [2/2]

const QgsVectorLayerEditBuffer * QgsVectorLayer::editBuffer ( ) const

inline

Buffer with uncommitted editing operations.

Only valid after editing has been turned on.

Note

not available in Python bindings

Definition at line 2017 of file qgsvectorlayer.h.

editCommandDestroyed

void QgsVectorLayer::editCommandDestroyed ( )

signal

Signal emitted, when an edit command is destroyed.

Note

This is not a rollback, it is only related to the current edit command. See beforeRollBack()

editCommandEnded

void QgsVectorLayer::editCommandEnded ( )

signal

Signal emitted, when an edit command successfully ended.

Note

This does not mean it is also committed, only that it is written to the edit buffer. See beforeCommitChanges()

editCommandStarted

void QgsVectorLayer::editCommandStarted ( const QString &  text )

signal

Signal emitted when a new edit command has been started.

Parameters

text	Description for this edit command

editFormConfig()

QgsEditFormConfig QgsVectorLayer::editFormConfig

(

)

const

Returns the configuration of the form used to represent this vector layer.

Returns

The configuration of this layers' form

Definition at line 5636 of file qgsvectorlayer.cpp.

editFormConfigChanged

void QgsVectorLayer::editFormConfigChanged ( )

signal

Will be emitted whenever the edit form configuration of this layer changes.

editorWidgetSetup()

QgsEditorWidgetSetup QgsVectorLayer::editorWidgetSetup

(

int

index

)

const

The editor widget setup defines which QgsFieldFormatter and editor widget will be used for the field at index.

Definition at line 6249 of file qgsvectorlayer.cpp.

elevationProperties()

QgsMapLayerElevationProperties * QgsVectorLayer::elevationProperties ( )

overridevirtual

Returns the layer's elevation properties.

This may be nullptr, depending on the layer type.

Since

QGIS 3.18

Reimplemented from QgsMapLayer.

Definition at line 777 of file qgsvectorlayer.cpp.

encodedSource()

QString QgsVectorLayer::encodedSource ( const QString &  source, const QgsReadWriteContext &  context  ) const

virtual

Called by writeLayerXML(), used by derived classes to encode provider's specific data source to project files.

Typically resolving absolute or relative paths, usernames and passwords or drivers prefixes ("HDF5:")

Parameters

source	data source to encode, typically QgsMapLayer::source()
context	writing context (e.g. for conversion between relative and absolute paths)

Returns

encoded source, typically to be written in the DOM element "datasource"

Since

QGIS 3.2

Reimplemented from QgsMapLayer.

Definition at line 2374 of file qgsvectorlayer.cpp.

endEditCommand()

void QgsVectorLayer::endEditCommand

(

)

Finish edit command and add it to undo/redo stack.

Definition at line 4288 of file qgsvectorlayer.cpp.

excludeAttributesWfs()

QSet< QString > QgsVectorLayer::excludeAttributesWfs

(

)

const

A set of attributes that are not advertised in WFS requests with QGIS server.

Deprecated:

since QGIS 3.16, use fields().configurationFlags() instead

Definition at line 3595 of file qgsvectorlayer.cpp.

excludeAttributesWms()

QSet< QString > QgsVectorLayer::excludeAttributesWms

(

)

const

A set of attributes that are not advertised in WMS requests with QGIS server.

Deprecated:

since QGIS 3.16, use fields().configurationFlags() instead

Definition at line 3567 of file qgsvectorlayer.cpp.

expressionField()

QString QgsVectorLayer::expressionField

(

int

index

)

const

Returns the expression used for a given expression field.

Parameters

index

An index of an epxression based (virtual) field

Returns

The expression for the field at index

Definition at line 4378 of file qgsvectorlayer.cpp.

extent()

QgsRectangle QgsVectorLayer::extent ( ) const

virtual

Returns the extent of the layer.

Reimplemented from QgsMapLayer.

Definition at line 1025 of file qgsvectorlayer.cpp.

extent3D()

QgsBox3D QgsVectorLayer::extent3D ( ) const

virtual

Returns the 3D extent of the layer.

Since

QGIS 3.36

Reimplemented from QgsMapLayer.

Definition at line 1120 of file qgsvectorlayer.cpp.

featureAdded

void QgsVectorLayer::featureAdded ( QgsFeatureId  fid )

signal

Emitted when a new feature has been added to the layer.

Parameters

fid	The id of the new feature

featureBlendMode()

QPainter::CompositionMode QgsVectorLayer::featureBlendMode

(

)

const

Returns the current blending mode for features.

Definition at line 5079 of file qgsvectorlayer.cpp.

featureBlendModeChanged

void QgsVectorLayer::featureBlendModeChanged ( QPainter::CompositionMode  blendMode )

signal

Signal emitted when setFeatureBlendMode() is called.

featureCount() [1/2]

long long QgsVectorLayer::featureCount ( ) const

virtual

Returns feature count including changes which have not yet been committed If you need only the count of committed features call this method on this layer's provider.

Returns

the number of features on this layer or -1 if unknown.

Implements QgsFeatureSource.

Definition at line 3805 of file qgsvectorlayer.cpp.

featureCount() [2/2]

long long QgsVectorLayer::featureCount

(

const QString &

legendKey

)

const

Number of features rendered with specified legend key.

Features must be first calculated by countSymbolFeatures()

Returns

number of features rendered by symbol or -1 if failed or counts are not available

Definition at line 921 of file qgsvectorlayer.cpp.

featureDeleted

void QgsVectorLayer::featureDeleted ( QgsFeatureId  fid )

signal

Emitted when a feature has been deleted.

If you do expensive operations in a slot connected to this, you should prefer to use featuresDeleted( const QgsFeatureIds& ).

Parameters

fid	The id of the feature which has been deleted

featureRendererGenerators()

QList< const QgsFeatureRendererGenerator * > QgsVectorLayer::featureRendererGenerators

(

)

const

Returns a list of the feature renderer generators owned by the layer.

See also

addFeatureRendererGenerator()

removeFeatureRendererGenerator()

Since

QGIS 3.18

Definition at line 4259 of file qgsvectorlayer.cpp.

featuresDeleted

void QgsVectorLayer::featuresDeleted ( const QgsFeatureIds &  fids )

signal

Emitted when features have been deleted.

If features are deleted within an edit command, this will only be emitted once at the end to allow connected slots to minimize the overhead. If features are deleted outside of an edit command, this signal will be emitted once per feature.

Parameters

fids	The feature ids that have been deleted.

fieldConfigurationFlags()

Qgis::FieldConfigurationFlags QgsVectorLayer::fieldConfigurationFlags

(

int

index

)

const

Returns the configuration flags of the field at given index.

See also

QgsField::setConfigurationFlags()

Since

QGIS 3.16

Definition at line 6225 of file qgsvectorlayer.cpp.

fieldConstraints()

QgsFieldConstraints::Constraints QgsVectorLayer::fieldConstraints

(

int

fieldIndex

)

const

Returns any constraints which are present for a specified field index.

These constraints may be inherited from the layer's data provider or may be set manually on the vector layer from within QGIS.

See also

setFieldConstraint()

Definition at line 6086 of file qgsvectorlayer.cpp.

fieldConstraintsAndStrength()

QMap< QgsFieldConstraints::Constraint, QgsFieldConstraints::ConstraintStrength > QgsVectorLayer::fieldConstraintsAndStrength

(

int

fieldIndex

)

const

Returns a map of constraint with their strength for a specific field of the layer.

Parameters

fieldIndex

field index

Definition at line 6104 of file qgsvectorlayer.cpp.

fields()

QgsFields QgsVectorLayer::fields ( ) const

virtual

Returns the list of fields of this layer.

This also includes fields which have not yet been saved to the provider.

Returns

A list of fields

Implements QgsFeatureSource.

Definition at line 3778 of file qgsvectorlayer.cpp.

geometryChanged

void QgsVectorLayer::geometryChanged ( QgsFeatureId  fid, const QgsGeometry &  geometry  )

signal

Emitted whenever a geometry change is done in the edit buffer.

Note that at this point the geometry change is not yet saved to the provider.

Parameters

fid	The id of the changed feature
geometry	The new geometry

geometryOptions()

QgsGeometryOptions * QgsVectorLayer::geometryOptions

(

)

const

Configuration and logic to apply automatically on any edit happening on this layer.

Since

QGIS 3.4

Definition at line 6305 of file qgsvectorlayer.cpp.

geometryType()

Qgis::GeometryType QgsVectorLayer::geometryType

(

)

const

Returns point, line or polygon.

Definition at line 814 of file qgsvectorlayer.cpp.

getFeature()

QgsFeature QgsVectorLayer::getFeature ( QgsFeatureId  fid ) const

inline

Queries the layer for the feature with the given id.

If there is no such feature, the returned feature will be invalid.

Definition at line 1146 of file qgsvectorlayer.h.

getFeatures() [1/4]

QgsFeatureIterator QgsVectorLayer::getFeatures ( const QgsFeatureIds &  fids )

inline

Queries the layer for the features with the given ids.

Definition at line 1162 of file qgsvectorlayer.h.

getFeatures() [2/4]

QgsFeatureIterator QgsVectorLayer::getFeatures ( const QgsFeatureRequest &  request = QgsFeatureRequest() ) const

virtual

Queries the layer for features specified in request.

Parameters

request

feature request describing parameters of features to return

Returns

iterator for matching features from provider

Implements QgsFeatureSource.

Definition at line 1304 of file qgsvectorlayer.cpp.

getFeatures() [3/4]

QgsFeatureIterator QgsVectorLayer::getFeatures ( const QgsRectangle &  rectangle )

inline

Queries the layer for the features which intersect the specified rectangle.

Definition at line 1170 of file qgsvectorlayer.h.

getFeatures() [4/4]

QgsFeatureIterator QgsVectorLayer::getFeatures ( const QString &  expression )

inline

Queries the layer for features matching a given expression.

Definition at line 1137 of file qgsvectorlayer.h.

getGeometry()

QgsGeometry QgsVectorLayer::getGeometry

(

QgsFeatureId

fid

)

const

Queries the layer for the geometry at the given id.

If there is no such feature, the returned geometry will be invalid.

Definition at line 1315 of file qgsvectorlayer.cpp.

getSelectedFeatures()

QgsFeatureIterator QgsVectorLayer::getSelectedFeatures

(

QgsFeatureRequest

request = QgsFeatureRequest()

)

const

Returns an iterator of the selected features.

Parameters

request

You may specify a request, e.g. to limit the set of requested attributes. Any filter on the request will be discarded.

Returns

Iterator over the selected features

Warning

Calling this method returns an iterator for all attributes and geometry for the selected features. Consider using the much more efficient selectedFeatureIds() or selectedFeatureCount() if you do not require access to the feature attributes or geometry.

See also

selectedFeatureIds()

selectedFeatures()

Definition at line 4006 of file qgsvectorlayer.cpp.

hasFeatures()

Qgis::FeatureAvailability QgsVectorLayer::hasFeatures ( ) const

virtual

Determines if this vector layer has features.

Warning

when a layer is editable and some features have been deleted, this will return QgsFeatureSource::FeatureAvailability::FeaturesMayBeAvailable to avoid a potentially expensive call to the dataprovider.

Since

QGIS 3.4

Reimplemented from QgsFeatureSource.

Definition at line 3815 of file qgsvectorlayer.cpp.

hasMapTips()

bool QgsVectorLayer::hasMapTips ( ) const

virtual

Returns true if the layer contains map tips.

See also

mapTipTemplate()

setMapTipTemplate()

Reimplemented from QgsMapLayer.

Definition at line 4104 of file qgsvectorlayer.cpp.

hasSpatialIndex

Qgis::SpatialIndexPresence QgsVectorLayer::hasSpatialIndex ( ) const

overrideslot

Definition at line 1845 of file qgsvectorlayer.cpp.

htmlMetadata()

QString QgsVectorLayer::htmlMetadata ( ) const

virtual

Obtain a formatted HTML string containing assorted metadata for this layer.

Reimplemented from QgsMapLayer.

Definition at line 5702 of file qgsvectorlayer.cpp.

insertVertex() [1/2]

bool QgsVectorLayer::insertVertex	(	const QgsPoint &	point,
		QgsFeatureId	atFeatureId,
		int	beforeVertex
	)

Inserts a new vertex before the given vertex number, in the given ring, item (first number is index 0), and feature.

Not meaningful for Point geometries

Note

Calls to insertVertex() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1430 of file qgsvectorlayer.cpp.

insertVertex() [2/2]

bool QgsVectorLayer::insertVertex	(	double	x,
		double	y,
		QgsFeatureId	atFeatureId,
		int	beforeVertex
	)

Inserts a new vertex before the given vertex number, in the given ring, item (first number is index 0), and feature.

Not meaningful for Point geometries

Note

Calls to insertVertex() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1415 of file qgsvectorlayer.cpp.

invertSelection()

void QgsVectorLayer::invertSelection

(

)

Selects not selected features and deselects selected ones.

Definition at line 677 of file qgsvectorlayer.cpp.

invertSelectionInRectangle()

void QgsVectorLayer::invertSelectionInRectangle

(

QgsRectangle &

rect

)

Inverts selection of features found within the search rectangle (in layer's coordinates)

Parameters

rect	The rectangle in which the selection of features will be inverted

See also

invertSelection()

Definition at line 693 of file qgsvectorlayer.cpp.

isAuxiliaryField()

bool QgsVectorLayer::isAuxiliaryField	(	int	index,
		int &	srcIndex
	)		const

Returns true if the field comes from the auxiliary layer, false otherwise.

Definition at line 4173 of file qgsvectorlayer.cpp.

isEditable()

bool QgsVectorLayer::isEditable ( ) const

virtual

Returns true if the provider is in editing mode.

Reimplemented from QgsMapLayer.

Definition at line 4112 of file qgsvectorlayer.cpp.

isEditCommandActive()

bool QgsVectorLayer::isEditCommandActive ( ) const

inline

Tests if an edit command is active.

Definition at line 2361 of file qgsvectorlayer.h.

isModified()

bool QgsVectorLayer::isModified ( ) const

overridevirtual

Returns true if the provider has been modified since the last commit.

Reimplemented from QgsMapLayer.

Definition at line 4165 of file qgsvectorlayer.cpp.

isSpatial()

bool QgsVectorLayer::isSpatial ( ) const

virtual

Returns true if this is a geometry layer and false in case of NoGeometry (table only) or UnknownGeometry.

Reimplemented from QgsMapLayer.

Definition at line 4119 of file qgsvectorlayer.cpp.

isSqlQuery()

bool QgsVectorLayer::isSqlQuery

(

)

const

Returns true if the layer is a query (SQL) layer.

Note

this is simply a shortcut to check if the SqlQuery flag is set.

See also

vectorLayerTypeFlags()

Since

QGIS 3.24

Definition at line 416 of file qgsvectorlayer.cpp.

joinBuffer() [1/2]

QgsVectorLayerJoinBuffer * QgsVectorLayer::joinBuffer ( )

inline

Returns the join buffer object.

Definition at line 703 of file qgsvectorlayer.h.

joinBuffer() [2/2]

const QgsVectorLayerJoinBuffer * QgsVectorLayer::joinBuffer ( ) const

inline

Returns a const pointer on join buffer object.

Since

QGIS 3.10

Definition at line 709 of file qgsvectorlayer.h.

labeling() [1/2]

QgsAbstractVectorLayerLabeling * QgsVectorLayer::labeling ( )

inline

Access to labeling configuration.

May be nullptr if labeling is not used.

Note

Labels will only be rendered if labelsEnabled() returns true.

See also

labelsEnabled()

Definition at line 1620 of file qgsvectorlayer.h.

labeling() [2/2]

const QgsAbstractVectorLayerLabeling * QgsVectorLayer::labeling ( ) const

inline

Access to const labeling configuration.

May be nullptr if labeling is not used.

Note

Labels will only be rendered if labelsEnabled() returns true.

See also

labelsEnabled()

Definition at line 1613 of file qgsvectorlayer.h.

labelingFontNotFound

void QgsVectorLayer::labelingFontNotFound ( QgsVectorLayer *  layer, const QString &  fontfamily  )

signal

Emitted when the font family defined for labeling layer is not found on system.

labelsEnabled()

bool QgsVectorLayer::labelsEnabled

(

)

const

Returns whether the layer contains labels which are enabled and should be drawn.

Returns

true if layer contains enabled labels

See also

setLabelsEnabled()

Definition at line 890 of file qgsvectorlayer.cpp.

loadAuxiliaryLayer()

bool QgsVectorLayer::loadAuxiliaryLayer	(	const QgsAuxiliaryStorage &	storage,
		const QString &	key = QString()
	)

Loads the auxiliary layer for this vector layer.

If there's no corresponding table in the database, then nothing happens and false is returned. The key is optional because if this layer has been read from a XML document, then the key read in this document is used by default.

Parameters

storage	The auxiliary storage where to look for the table
key	The key to use for joining.

Returns

true if the auxiliary layer is well loaded, false otherwise

Definition at line 5928 of file qgsvectorlayer.cpp.

loadDefaultStyle()

QString QgsVectorLayer::loadDefaultStyle ( bool &  resultFlag )

virtual

Retrieve the default style for this layer if one exists (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)

Parameters

resultFlag

a reference to a flag that will be set to false if we did not manage to load the default style.

Returns

a QString with any status messages

See also

loadNamedStyle()

Reimplemented from QgsMapLayer.

Definition at line 2079 of file qgsvectorlayer.cpp.

maximumValue()

QVariant QgsVectorLayer::maximumValue ( int  index ) const

virtual

Returns the maximum value for an attribute column or an invalid variant in case of error.

Note

In some circumstances when unsaved changes are present for the layer then the returned value may be outdated (for instance when the attribute value in a saved feature has been changed inside the edit buffer then the previous saved value may be returned as the maximum).

If both the minimum and maximum value are required it is more efficient to call minimumAndMaximumValue() instead of separate calls to minimumValue() and maximumValue().

See also

minimumValue()

minimumAndMaximumValue()

uniqueValues()

Reimplemented from QgsFeatureSource.

Definition at line 4836 of file qgsvectorlayer.cpp.

minimumAndMaximumValue()

void QgsVectorLayer::minimumAndMaximumValue	(	int	index,
		QVariant &	minimum,
		QVariant &	maximum
	)		const

Calculates both the minimum and maximum value for an attribute column.

This is more efficient then calling both minimumValue() and maximumValue() when both the minimum and maximum values are required.

Parameters

index	index of field to calculate minimum and maximum value for.
minimum	will be set to minimum attribute value or an invalid variant in case of error.
maximum	will be set to maximum attribute value or an invalid variant in case of error.

Note

In some circumstances when unsaved changes are present for the layer then the calculated values may be outdated (for instance when the attribute value in a saved feature has been changed inside the edit buffer then the previous saved value may be returned as the maximum).

See also

minimumValue()

maximumValue()

Since

QGIS 3.20

Definition at line 4845 of file qgsvectorlayer.cpp.

minimumValue()

QVariant QgsVectorLayer::minimumValue ( int  index ) const

virtual

Returns the minimum value for an attribute column or an invalid variant in case of error.

Note

In some circumstances when unsaved changes are present for the layer then the returned value may be outdated (for instance when the attribute value in a saved feature has been changed inside the edit buffer then the previous saved value may be returned as the minimum).

If both the minimum and maximum value are required it is more efficient to call minimumAndMaximumValue() instead of separate calls to minimumValue() and maximumValue().

See also

maximumValue()

minimumAndMaximumValue()

uniqueValues()

Reimplemented from QgsFeatureSource.

Definition at line 4827 of file qgsvectorlayer.cpp.

modifySelection()

void QgsVectorLayer::modifySelection	(	const QgsFeatureIds &	selectIds,
		const QgsFeatureIds &	deselectIds
	)

Modifies the current selection on this layer.

Parameters

selectIds	Select these ids
deselectIds	Deselect these ids

See also

selectByIds

deselect(const QgsFeatureIds&)

deselect(const QgsFeatureId)

selectByExpression()

Definition at line 660 of file qgsvectorlayer.cpp.

moveVertex() [1/2]

bool QgsVectorLayer::moveVertex	(	const QgsPoint &	p,
		QgsFeatureId	atFeatureId,
		int	atVertex
	)

Moves the vertex at the given position number, ring and item (first number is index 0), and feature to the given coordinates.

Note

available in Python as moveVertexV2

Calls to moveVertex() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1460 of file qgsvectorlayer.cpp.

moveVertex() [2/2]

bool QgsVectorLayer::moveVertex	(	double	x,
		double	y,
		QgsFeatureId	atFeatureId,
		int	atVertex
	)

Moves the vertex at the given position number, ring and item (first number is index 0), and feature to the given coordinates.

Note

Calls to moveVertex() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1445 of file qgsvectorlayer.cpp.

operator=()

QgsVectorLayer & QgsVectorLayer::operator= ( QgsVectorLayer const &  rhs )

delete

QgsVectorLayer cannot be copied.

primaryKeyAttributes()

QgsAttributeList QgsVectorLayer::primaryKeyAttributes

(

)

const

Returns the list of attributes which make up the layer's primary keys.

Definition at line 3786 of file qgsvectorlayer.cpp.

raiseError

void QgsVectorLayer::raiseError ( const QString &  msg )

signal

Signals an error related to this vector layer.

readCustomSymbology

void QgsVectorLayer::readCustomSymbology ( const QDomElement &  element, QString &  errorMessage  )

signal

Signal emitted whenever the symbology (QML-file) for this layer is being read.

If there is custom style information saved in the file, you can connect to this signal and update the layer style accordingly.

Parameters

element	The XML layer style element.
errorMessage	Write error messages into this string.

readExtentFromXml()

bool QgsVectorLayer::readExtentFromXml

(

)

const

Returns true if the extent is read from the XML document when data source has no metadata, false if it's the data provider which determines it.

Definition at line 6319 of file qgsvectorlayer.cpp.

readOnlyChanged

void QgsVectorLayer::readOnlyChanged ( )

signal

Emitted when the read only state of this layer is changed.

Only applies to manually set readonly state, not to the edit mode.

See also

setReadOnly()

readSld()

bool QgsVectorLayer::readSld ( const QDomNode &  node, QString &  errorMessage  )

virtual

Reimplemented from QgsMapLayer.

Definition at line 3247 of file qgsvectorlayer.cpp.

readStyle()

bool QgsVectorLayer::readStyle	(	const QDomNode &	node,
		QString &	errorMessage,
		QgsReadWriteContext &	context,
		QgsMapLayer::StyleCategories	categories = QgsMapLayer::AllStyleCategories
	)

Definition at line 2722 of file qgsvectorlayer.cpp.

readSymbology()

bool QgsVectorLayer::readSymbology	(	const QDomNode &	layerNode,
		QString &	errorMessage,
		QgsReadWriteContext &	context,
		QgsMapLayer::StyleCategories	categories = QgsMapLayer::AllStyleCategories
	)

Definition at line 2405 of file qgsvectorlayer.cpp.

readXml()

bool QgsVectorLayer::readXml ( const QDomNode &  layer_node, QgsReadWriteContext &  context  )

virtual

Reads vector layer specific state from project file Dom node.

Note

Called by QgsMapLayer::readXml().

Reimplemented from QgsMapLayer.

Definition at line 1867 of file qgsvectorlayer.cpp.

referencingRelations()

QList< QgsRelation > QgsVectorLayer::referencingRelations

(

int

idx

)

const

Returns the layer's relations, where the foreign key is on this layer.

Parameters

idx	Only get relations, where idx forms part of the foreign key

Returns

A list of relations

Definition at line 5907 of file qgsvectorlayer.cpp.

reload()

void QgsVectorLayer::reload ( )

virtual

Synchronises with changes in the datasource.

Reimplemented from QgsMapLayer.

Definition at line 455 of file qgsvectorlayer.cpp.

removeExpressionField()

void QgsVectorLayer::removeExpressionField

(

int

index

)

Removes an expression field.

Parameters

index

The index of the field

Definition at line 4367 of file qgsvectorlayer.cpp.

removeFeatureRendererGenerator()

void QgsVectorLayer::removeFeatureRendererGenerator

(

const QString &

id

)

Removes the feature renderer with matching id from the layer.

The corresponding generator will be deleted.

See also

addFeatureRendererGenerator()

featureRendererGenerators()

Since

QGIS 3.18

Definition at line 4245 of file qgsvectorlayer.cpp.

removeFieldAlias()

void QgsVectorLayer::removeFieldAlias

(

int

index

)

Removes an alias (a display name) for attributes to display in dialogs.

Definition at line 3451 of file qgsvectorlayer.cpp.

removeFieldConstraint()

void QgsVectorLayer::removeFieldConstraint	(	int	index,
		QgsFieldConstraints::Constraint	constraint
	)

Removes a constraint for a specified field index.

Any constraints inherited from the layer's data provider will be kept intact and cannot be removed.

See also

fieldConstraints()

setFieldConstraint()

Definition at line 6146 of file qgsvectorlayer.cpp.

removeJoin()

bool QgsVectorLayer::removeJoin

(

const QString &

joinLayerId

)

Removes a vector layer join.

Returns

true if join was found and successfully removed

Definition at line 4341 of file qgsvectorlayer.cpp.

removeSelection

void QgsVectorLayer::removeSelection ( )

slot

Clear selection.

See also

selectByIds()

reselect()

Definition at line 724 of file qgsvectorlayer.cpp.

renameAttribute()

bool QgsVectorLayer::renameAttribute	(	int	index,
		const QString &	newName
	)

Renames an attribute field (but does not commit it).

Parameters

index	attribute index
newName	new name of field

Note

Calls to renameAttribute() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 3469 of file qgsvectorlayer.cpp.

renderer() [1/2]

QgsFeatureRenderer * QgsVectorLayer::renderer ( )

inline

Returns the feature renderer used for rendering the features in the layer in 2D map views.

See also

setRenderer()

Definition at line 933 of file qgsvectorlayer.h.

renderer() [2/2]

const QgsFeatureRenderer * QgsVectorLayer::renderer ( ) const

inline

Returns the feature renderer used for rendering the features in the layer in 2D map views.

See also

setRenderer()

Note

not available in Python bindings

Definition at line 942 of file qgsvectorlayer.h.

reselect

void QgsVectorLayer::reselect ( )

slot

Reselects the previous set of selected features.

This is only applicable after a prior call to removeSelection().

Any other modifications to the selection following a call to removeSelection() clears memory of the previous selection and consequently calling reselect() has no impact.

See also

removeSelection()

Since

QGIS 3.10

Definition at line 736 of file qgsvectorlayer.cpp.

resolveReferences()

void QgsVectorLayer::resolveReferences ( QgsProject *  project )

virtual

Resolves references to other layers (kept as layer IDs after reading XML) into layer objects.

Reimplemented from QgsMapLayer.

Definition at line 2396 of file qgsvectorlayer.cpp.

rollBack()

bool QgsVectorLayer::rollBack

(

bool

deleteBuffer = true

)

Stops a current editing operation and discards any uncommitted edits.

If deleteBuffer is true the editing buffer will be completely deleted (the default behavior).

See also

startEditing()

commitChanges()

Definition at line 3919 of file qgsvectorlayer.cpp.

select [1/2]

void QgsVectorLayer::select ( const QgsFeatureIds &  featureIds )

slot

Selects features by their ID.

Parameters

featureIds

The ids of the features to select

See also

select(QgsFeatureId)

Definition at line 507 of file qgsvectorlayer.cpp.

select [2/2]

void QgsVectorLayer::select ( QgsFeatureId  featureId )

slot

Selects feature by its ID.

Parameters

featureId

The id of the feature to select

See also

select( const QgsFeatureIds& )

Definition at line 497 of file qgsvectorlayer.cpp.

selectAll()

void QgsVectorLayer::selectAll

(

)

Select all the features.

Definition at line 686 of file qgsvectorlayer.cpp.

selectByExpression()

void QgsVectorLayer::selectByExpression	(	const QString &	expression,
		Qgis::SelectBehavior	behavior = Qgis::SelectBehavior::SetSelection,
		QgsExpressionContext *	context = nullptr
	)

Selects matching features using an expression.

Parameters

expression	expression to evaluate to select features
behavior	selection type, allows adding to current selection, removing from selection, etc.
context	since QGIS 3.26, specifies an optional expression context to use when selecting features. If not specified a default one will be built.

See also

selectByRect()

selectByIds()

Definition at line 561 of file qgsvectorlayer.cpp.

selectByIds()

void QgsVectorLayer::selectByIds	(	const QgsFeatureIds &	ids,
		Qgis::SelectBehavior	behavior = Qgis::SelectBehavior::SetSelection
	)

Selects matching features using a list of feature IDs.

Will emit the selectionChanged() signal with the clearAndSelect flag set.

Parameters

ids	feature IDs to select
behavior	selection type, allows adding to current selection, removing from selection, etc.

See also

selectByRect()

selectByExpression()

Definition at line 628 of file qgsvectorlayer.cpp.

selectByRect()

void QgsVectorLayer::selectByRect	(	QgsRectangle &	rect,
		Qgis::SelectBehavior	behavior = Qgis::SelectBehavior::SetSelection
	)

Selects features found within the search rectangle (in layer's coordinates)

Parameters

rect	search rectangle
behavior	selection type, allows adding to current selection, removing from selection, etc.

See also

invertSelectionInRectangle(QgsRectangle & rect)

selectByExpression()

selectByIds()

Definition at line 537 of file qgsvectorlayer.cpp.

selectedFeatureCount()

int QgsVectorLayer::selectedFeatureCount

(

)

const

Returns the number of features that are selected in this layer.

See also

selectedFeatureIds()

Definition at line 3973 of file qgsvectorlayer.cpp.

selectedFeatureIds()

const QgsFeatureIds & QgsVectorLayer::selectedFeatureIds

(

)

const

Returns a list of the selected features IDs in this layer.

See also

selectedFeatures()

selectedFeatureCount()

selectByIds()

Definition at line 3980 of file qgsvectorlayer.cpp.

selectedFeatures()

QgsFeatureList QgsVectorLayer::selectedFeatures

(

)

const

Returns a copy of the user-selected features.

Warning

Calling this method triggers a request for all attributes and geometry for the selected features. Consider using the much more efficient selectedFeatureIds() or selectedFeatureCount() if you do not require access to the feature attributes or geometry.

Returns

A list of QgsFeature

See also

selectedFeatureIds()

getSelectedFeatures() which is more memory friendly when handling large selections

Definition at line 3988 of file qgsvectorlayer.cpp.

selectionChanged

void QgsVectorLayer::selectionChanged ( const QgsFeatureIds &  selected, const QgsFeatureIds &  deselected, bool  clearAndSelect  )

signal

Emitted when selection was changed.

Parameters

selected	Newly selected feature ids
deselected	Ids of all features which have previously been selected but are not any more
clearAndSelect	In case this is set to true, the old selection was dismissed and the new selection corresponds to selected

selectionProperties()

QgsMapLayerSelectionProperties * QgsVectorLayer::selectionProperties ( )

overridevirtual

Returns the layer's selection properties.

This may be nullptr, depending on the layer type.

Since

QGIS 3.34

Reimplemented from QgsMapLayer.

Definition at line 762 of file qgsvectorlayer.cpp.

setAllowCommit()

void QgsVectorLayer::setAllowCommit

(

bool

allowCommit

)

Controls, if the layer is allowed to commit changes.

If this is set to false it will not be possible to commit changes on this layer. This can be used to define checks on a layer that need to be pass before the layer can be saved. If you use this API, make sure that:

• the user is visibly informed that his changes were not saved and what he needs to do in order to be able to save the changes.
• to set the property back to true, once the user has fixed his data.

When calling

See also

commitChanges() this flag is checked just after the

beforeCommitChanges() signal is emitted, so it's possible to adjust it from there.

Note

Not available in Python bindings

Since

QGIS 3.4

Definition at line 6294 of file qgsvectorlayer.cpp.

setAttributeTableConfig()

void QgsVectorLayer::setAttributeTableConfig

(

const QgsAttributeTableConfig &

attributeTableConfig

)

Sets the attribute table configuration object.

This defines the appearance of the attribute table.

Definition at line 5667 of file qgsvectorlayer.cpp.

setAuxiliaryLayer()

void QgsVectorLayer::setAuxiliaryLayer

(

QgsAuxiliaryLayer *

layer = nullptr

)

Sets the current auxiliary layer.

The auxiliary layer is automatically put in editable mode and fields are updated. Moreover, a join is created between the current layer and the auxiliary layer. Ownership is transferred.

Definition at line 5959 of file qgsvectorlayer.cpp.

setConstraintExpression()

void QgsVectorLayer::setConstraintExpression	(	int	index,
		const QString &	expression,
		const QString &	description = QString()
	)

Sets the constraint expression for the specified field index.

An optional descriptive name for the constraint can also be set. Setting an empty expression will clear any existing expression constraint.

See also

constraintExpression()

constraintDescription()

fieldConstraints()

Definition at line 6185 of file qgsvectorlayer.cpp.

setCoordinateSystem()

void QgsVectorLayer::setCoordinateSystem

(

)

Setup the coordinate system transformation for the layer.

Definition at line 4050 of file qgsvectorlayer.cpp.

setDefaultValueDefinition()

void QgsVectorLayer::setDefaultValueDefinition	(	int	index,
		const QgsDefaultValue &	definition
	)

Sets the definition of the expression to use when calculating the default value for a field.

Parameters

index	field index
definition	default value definition to use and evaluate when calculating default values for field. Pass an empty expression to clear the default.

See also

defaultValue()

defaultValueDefinition()

Definition at line 4586 of file qgsvectorlayer.cpp.

setDependencies()

bool QgsVectorLayer::setDependencies ( const QSet< QgsMapLayerDependency > &  layers )

virtual

Sets the list of dependencies.

See also

dependencies()

Parameters

layers

set of QgsMapLayerDependency. Only user-defined dependencies will be added

Returns

false if a dependency cycle has been detected

Reimplemented from QgsMapLayer.

Definition at line 6030 of file qgsvectorlayer.cpp.

setDiagramLayerSettings()

void QgsVectorLayer::setDiagramLayerSettings

(

const QgsDiagramLayerSettings &

s

)

Definition at line 5693 of file qgsvectorlayer.cpp.

setDiagramRenderer()

void QgsVectorLayer::setDiagramRenderer

(

QgsDiagramRenderer *

r

)

Sets diagram rendering object (takes ownership)

Definition at line 804 of file qgsvectorlayer.cpp.

setDisplayExpression()

void QgsVectorLayer::setDisplayExpression

(

const QString &

displayExpression

)

Set the preview expression, used to create a human readable preview string.

Used e.g. in the attribute table feature list. Uses QgsExpression.

Parameters

displayExpression

The expression which will be used to preview features for this layer

Definition at line 4071 of file qgsvectorlayer.cpp.

setEditFormConfig()

void QgsVectorLayer::setEditFormConfig

(

const QgsEditFormConfig &

editFormConfig

)

Sets the editFormConfig (configuration) of the form used to represent this vector layer.

See also

editFormConfig()

Definition at line 5643 of file qgsvectorlayer.cpp.

setEditorWidgetSetup()

void QgsVectorLayer::setEditorWidgetSetup	(	int	index,
		const QgsEditorWidgetSetup &	setup
	)

The editor widget setup defines which QgsFieldFormatter and editor widget will be used for the field at index.

Definition at line 6235 of file qgsvectorlayer.cpp.

setExcludeAttributesWfs()

void QgsVectorLayer::setExcludeAttributesWfs

(

const QSet< QString > &

att

)

A set of attributes that are not advertised in WFS requests with QGIS server.

Deprecated:

since QGIS 3.16, use setFieldConfigurationFlag instead

Definition at line 3611 of file qgsvectorlayer.cpp.

setExcludeAttributesWms()

void QgsVectorLayer::setExcludeAttributesWms

(

const QSet< QString > &

att

)

A set of attributes that are not advertised in WMS requests with QGIS server.

Deprecated:

since QGIS 3.16, use setFieldConfigurationFlag instead

Definition at line 3583 of file qgsvectorlayer.cpp.

setExtent()

void QgsVectorLayer::setExtent ( const QgsRectangle &  rect )

protectedvirtual

Sets the extent.

Reimplemented from QgsMapLayer.

Definition at line 989 of file qgsvectorlayer.cpp.

setExtent3D()

void QgsVectorLayer::setExtent3D ( const QgsBox3D &  rect )

protectedvirtual

Sets the extent.

Reimplemented from QgsMapLayer.

Definition at line 997 of file qgsvectorlayer.cpp.

setFeatureBlendMode()

void QgsVectorLayer::setFeatureBlendMode

(

QPainter::CompositionMode

blendMode

)

Sets the blending mode used for rendering each feature.

Definition at line 5067 of file qgsvectorlayer.cpp.

setFieldAlias()

void QgsVectorLayer::setFieldAlias	(	int	index,
		const QString &	aliasString
	)

Sets an alias (a display name) for attributes to display in dialogs.

Definition at line 3510 of file qgsvectorlayer.cpp.

setFieldConfigurationFlag()

void QgsVectorLayer::setFieldConfigurationFlag	(	int	index,
		Qgis::FieldConfigurationFlag	flag,
		bool	active
	)

Sets the given configuration flag for the field at given index to be active or not.

Since

QGIS 3.16

Definition at line 6214 of file qgsvectorlayer.cpp.

setFieldConfigurationFlags()

void QgsVectorLayer::setFieldConfigurationFlags	(	int	index,
		Qgis::FieldConfigurationFlags	flags
	)

Sets the configuration flags of the field at given index.

See also

QgsField::configurationFlags()

Since

QGIS 3.16

Definition at line 6203 of file qgsvectorlayer.cpp.

setFieldConstraint()

void QgsVectorLayer::setFieldConstraint	(	int	index,
		QgsFieldConstraints::Constraint	constraint,
		QgsFieldConstraints::ConstraintStrength	strength = QgsFieldConstraints::ConstraintStrengthHard
	)

Sets a constraint for a specified field index.

Any constraints inherited from the layer's data provider will be kept intact and cannot be modified. Ie, calling this method only allows for new constraints to be added on top of the existing provider constraints.

See also

fieldConstraints()

removeFieldConstraint()

Definition at line 6127 of file qgsvectorlayer.cpp.

setFieldSplitPolicy()

void QgsVectorLayer::setFieldSplitPolicy	(	int	index,
		Qgis::FieldDomainSplitPolicy	policy
	)

Sets a split policy for the field with the specified index.

Since

QGIS 3.30

Definition at line 3552 of file qgsvectorlayer.cpp.

setLabeling()

void QgsVectorLayer::setLabeling

(

QgsAbstractVectorLayerLabeling *

labeling

)

Sets labeling configuration.

Takes ownership of the object.

Definition at line 1789 of file qgsvectorlayer.cpp.

setLabelsEnabled()

void QgsVectorLayer::setLabelsEnabled

(

bool

enabled

)

Sets whether labels should be enabled for the layer.

Note

Labels will only be rendered if labelsEnabled() is true and a labeling object is returned by labeling().

See also

labelsEnabled()

labeling()

Definition at line 898 of file qgsvectorlayer.cpp.

setProviderEncoding()

void QgsVectorLayer::setProviderEncoding

(

const QString &

encoding

)

Sets the text encoding of the data provider.

An empty encoding string indicates that the provider should automatically select the most appropriate encoding.

Warning

Support for setting the provider encoding depends on the underlying data provider. Check dataProvider().capabilities() for the QgsVectorDataProvider::SelectEncoding capability in order to determine if the provider supports this ability.

Definition at line 793 of file qgsvectorlayer.cpp.

setReadExtentFromXml()

void QgsVectorLayer::setReadExtentFromXml

(

bool

readExtentFromXml

)

Flag allowing to indicate if the extent has to be read from the XML document when data source has no metadata or if the data provider has to determine it.

Definition at line 6312 of file qgsvectorlayer.cpp.

setReadOnly()

bool QgsVectorLayer::setReadOnly

(

bool

readonly = true

)

Makes layer read-only (editing disabled) or not.

Returns

false if the layer is in editing yet or if the data source is in read-only mode

See also

readOnlyChanged()

Definition at line 4135 of file qgsvectorlayer.cpp.

setRenderer()

void QgsVectorLayer::setRenderer

(

QgsFeatureRenderer *

r

)

Sets the feature renderer which will be invoked to represent this layer in 2D map views.

Ownership is transferred.

See also

renderer()

Definition at line 4194 of file qgsvectorlayer.cpp.

setSimplifyMethod()

void QgsVectorLayer::setSimplifyMethod ( const QgsVectorSimplifyMethod &  simplifyMethod )

inline

Sets the simplification settings for fast rendering of features.

Definition at line 2289 of file qgsvectorlayer.h.

setSubsetString()

bool QgsVectorLayer::setSubsetString ( const QString &  subset )

virtual

Sets the string (typically sql) used to define a subset of the layer.

Parameters

subset

The subset string. This may be the where clause of a sql statement or other definition string specific to the underlying dataprovider and data store.

Returns

true, when setting the subset string was successful, false otherwise

Definition at line 1247 of file qgsvectorlayer.cpp.

setTransformContext

void QgsVectorLayer::setTransformContext ( const QgsCoordinateTransformContext &  transformContext )

overridevirtualslot

Sets the coordinate transform context to transformContext.

Since

QGIS 3.8

Definition at line 1837 of file qgsvectorlayer.cpp.

setWeakRelations()

void QgsVectorLayer::setWeakRelations

(

const QList< QgsWeakRelation > &

relations

)

Sets the layer's weak relations.

Note

Not available in Python bindings.

See also

weakRelations()

Since

QGIS 3.28

Definition at line 5921 of file qgsvectorlayer.cpp.

simplifyDrawingCanbeApplied()

bool QgsVectorLayer::simplifyDrawingCanbeApplied	(	const QgsRenderContext &	renderContext,
		QgsVectorSimplifyMethod::SimplifyHint	simplifyHint
	)		const

Returns whether the VectorLayer can apply the specified simplification hint.

Note

Do not use in 3rd party code - may be removed in future version!

Definition at line 1282 of file qgsvectorlayer.cpp.

simplifyMethod()

const QgsVectorSimplifyMethod & QgsVectorLayer::simplifyMethod ( ) const

inline

Returns the simplification settings for fast rendering of features.

Definition at line 2294 of file qgsvectorlayer.h.

sourceCrs()

QgsCoordinateReferenceSystem QgsVectorLayer::sourceCrs ( ) const

virtual

Returns the coordinate reference system for features in the source.

Implements QgsFeatureSource.

Definition at line 441 of file qgsvectorlayer.cpp.

sourceExtent()

QgsRectangle QgsVectorLayer::sourceExtent ( ) const

virtual

Returns the extent of all geometries from the source.

The base class implementation uses a non-optimised approach of looping through all features in the source.

Reimplemented from QgsFeatureSource.

Definition at line 1221 of file qgsvectorlayer.cpp.

sourceExtent3D()

QgsBox3D QgsVectorLayer::sourceExtent3D ( ) const

virtual

Returns the 3D extent of all geometries from the source.

The base class implementation uses a non-optimised approach of looping through all features in the source.

Since

QGIS 3.36

Reimplemented from QgsFeatureSource.

Definition at line 1228 of file qgsvectorlayer.cpp.

sourceName()

QString QgsVectorLayer::sourceName ( ) const

virtual

Returns a friendly display name for the source.

The returned value can be an empty string.

Implements QgsFeatureSource.

Definition at line 448 of file qgsvectorlayer.cpp.

splitFeatures() [1/3]

Qgis::GeometryOperationResult QgsVectorLayer::splitFeatures	(	const QgsCurve *	curve,
		QgsPointSequence &	topologyTestPoints,
		bool	preserveCircular = false,
		bool	topologicalEditing = false
	)

Splits features cut by the given curve.

Parameters

	curve	curve that splits the layer features
[out]	topologyTestPoints	topological points to be tested against other layers
	preserveCircular	whether circular strings are preserved after splitting
	topologicalEditing	true if topological editing is enabled

Returns

Qgis::GeometryOperationResult

• Success
• NothingHappened
• LayerNotEditable
• InvalidInputGeometryType
• InvalidBaseGeometry
• GeometryEngineError
• SplitCannotSplitPoint

Note

Calls to splitFeatures() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Since

QGIS 3.16

Definition at line 1738 of file qgsvectorlayer.cpp.

splitFeatures() [2/3]

Qgis::GeometryOperationResult QgsVectorLayer::splitFeatures	(	const QgsPointSequence &	splitLine,
		bool	topologicalEditing = false
	)

Splits features cut by the given line.

Parameters

splitLine	line that splits the layer features
topologicalEditing	true if topological editing is enabled

Returns

Qgis::GeometryOperationResult

• Success
• NothingHappened
• LayerNotEditable
• InvalidInputGeometryType
• InvalidBaseGeometry
• GeometryEngineError
• SplitCannotSplitPoint

Note

Calls to splitFeatures() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1728 of file qgsvectorlayer.cpp.

splitFeatures() [3/3]

Qgis::GeometryOperationResult QgsVectorLayer::splitFeatures	(	const QVector< QgsPointXY > &	splitLine,
		bool	topologicalEditing = false
	)

Splits features cut by the given line.

Parameters

splitLine	line that splits the layer features
topologicalEditing	true if topological editing is enabled

Returns

Qgis::GeometryOperationResult

• Success
• NothingHappened
• LayerNotEditable
• InvalidInputGeometryType
• InvalidBaseGeometry
• GeometryEngineError
• SplitCannotSplitPoint

Note

Calls to splitFeatures() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Deprecated:

since QGIS 3.12 - will be removed in QGIS 4.0. Use the variant which accepts QgsPoint objects instead of QgsPointXY.

Definition at line 1721 of file qgsvectorlayer.cpp.

splitParts() [1/2]

Qgis::GeometryOperationResult QgsVectorLayer::splitParts	(	const QgsPointSequence &	splitLine,
		bool	topologicalEditing = false
	)

Splits parts cut by the given line.

Parameters

splitLine	line that splits the layer features
topologicalEditing	true if topological editing is enabled

Returns

Qgis::GeometryOperationResult

• Success
• NothingHappened
• LayerNotEditable
• InvalidInputGeometryType
• InvalidBaseGeometry
• GeometryEngineError
• SplitCannotSplitPoint

Note

Calls to splitParts() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1710 of file qgsvectorlayer.cpp.

splitParts() [2/2]

Qgis::GeometryOperationResult QgsVectorLayer::splitParts	(	const QVector< QgsPointXY > &	splitLine,
		bool	topologicalEditing = false
	)

Splits parts cut by the given line.

Parameters

splitLine	line that splits the layer features
topologicalEditing	true if topological editing is enabled

Returns

Qgis::GeometryOperationResult

• Success
• NothingHappened
• LayerNotEditable
• InvalidInputGeometryType
• InvalidBaseGeometry
• GeometryEngineError
• SplitCannotSplitPoint

Note

Calls to splitParts() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Deprecated:

since QGIS 3.12 - will be removed in QGIS 4.0. Use the variant which accepts QgsPoint objects instead of QgsPointXY.

Definition at line 1703 of file qgsvectorlayer.cpp.

startEditing

bool QgsVectorLayer::startEditing ( )

slot

Makes the layer editable.

This starts an edit session on this layer. Changes made in this edit session will not be made persistent until commitChanges() is called, and can be reverted by calling rollBack().

Returns

true if the layer was successfully made editable, or false if the operation failed (e.g. due to an underlying read-only data source, or lack of edit support by the backend data provider).

See also

commitChanges()

rollBack()

Definition at line 1800 of file qgsvectorlayer.cpp.

storageType()

QString QgsVectorLayer::storageType

(

)

const

Returns the permanent storage type for this layer as a friendly name.

This is obtained from the data provider and does not follow any standard.

Definition at line 393 of file qgsvectorlayer.cpp.

storedExpressionManager()

QgsStoredExpressionManager * QgsVectorLayer::storedExpressionManager ( )

inline

Returns the manager of the stored expressions for this layer.

Since

QGIS 3.10

Definition at line 2413 of file qgsvectorlayer.h.

subsetString()

QString QgsVectorLayer::subsetString ( ) const

virtual

Returns the string (typically sql) used to define a subset of the layer.

Returns

The subset string or null QString if not implemented by the provider

Definition at line 1235 of file qgsvectorlayer.cpp.

subsetStringChanged

void QgsVectorLayer::subsetStringChanged ( )

signal

Emitted when the layer's subset string has changed.

Since

QGIS 3.2

supportsEditing()

bool QgsVectorLayer::supportsEditing ( ) const

overridevirtual

Returns whether the layer supports editing or not.

Returns

false if the layer is read only or the data provider has no editing capabilities

Since

QGIS 3.18

Reimplemented from QgsMapLayer.

Definition at line 4152 of file qgsvectorlayer.cpp.

supportsEditingChanged

void QgsVectorLayer::supportsEditingChanged ( )

signal

Emitted when the read only state or the data provider of this layer is changed.

Since

QGIS 3.18

symbolFeatureCountMapChanged

void QgsVectorLayer::symbolFeatureCountMapChanged ( )

signal

Emitted when the feature count for symbols on this layer has been recalculated.

symbolFeatureIds()

QgsFeatureIds QgsVectorLayer::symbolFeatureIds

(

const QString &

legendKey

)

const

Ids of features rendered with specified legend key.

Features must be first calculated by countSymbolFeatures()

Returns

Ids of features rendered by symbol or -1 if failed or Ids are not available

Since

QGIS 3.10

Definition at line 931 of file qgsvectorlayer.cpp.

temporalProperties()

QgsMapLayerTemporalProperties * QgsVectorLayer::temporalProperties ( )

overridevirtual

Returns the layer's temporal properties.

This may be nullptr, depending on the layer type.

Since

QGIS 3.14

Reimplemented from QgsMapLayer.

Definition at line 770 of file qgsvectorlayer.cpp.

translateFeature()

int QgsVectorLayer::translateFeature	(	QgsFeatureId	featureId,
		double	dx,
		double	dy
	)

Translates feature by dx, dy.

Parameters

featureId	id of the feature to translate
dx	translation of x-coordinate
dy	translation of y-coordinate

Returns

0 in case of success

Note

Calls to translateFeature() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Definition at line 1688 of file qgsvectorlayer.cpp.

uniqueStringsMatching()

QStringList QgsVectorLayer::uniqueStringsMatching	(	int	index,
		const QString &	substring,
		int	limit = -1,
		QgsFeedback *	feedback = nullptr
	)		const

Returns unique string values of an attribute which contain a specified subset string.

Subset matching is done in a case-insensitive manner. Note that in some circumstances when unsaved changes are present for the layer then the returned list may contain outdated values (for instance when the attribute value in a saved feature has been changed inside the edit buffer then the previous saved value will be included in the returned list).

Parameters

index	column index for attribute
substring	substring to match (case insensitive)
limit	maxmum number of the values to return, or -1 to return all unique values
feedback	optional feedback object for canceling request

Returns

list of unique strings containing substring

Definition at line 4724 of file qgsvectorlayer.cpp.

uniqueValues()

QSet< QVariant > QgsVectorLayer::uniqueValues ( int  fieldIndex, int  limit = -1  ) const

virtual

Calculates a list of unique values contained within an attribute in the layer.

Note that in some circumstances when unsaved changes are present for the layer then the returned list may contain outdated values (for instance when the attribute value in a saved feature has been changed inside the edit buffer then the previous saved value will be included in the returned list).

Parameters

fieldIndex	column index for attribute
limit	maximum number of values to return (or -1 if unlimited)

See also

minimumValue()

maximumValue()

Reimplemented from QgsFeatureSource.

Definition at line 4614 of file qgsvectorlayer.cpp.

updatedFields

void QgsVectorLayer::updatedFields ( )

signal

Emitted whenever the fields available from this layer have been changed.

This can be due to manually adding attributes or due to a join.

updateExpressionField()

void QgsVectorLayer::updateExpressionField	(	int	index,
		const QString &	exp
	)

Changes the expression used to define an expression based (virtual) field.

Parameters

index	The index of the expression to change
exp	The new expression to set

Definition at line 4392 of file qgsvectorlayer.cpp.

updateExtents

void QgsVectorLayer::updateExtents ( bool  force = false )

virtualslot

Update the extents for the layer.

This is necessary if features are added/deleted or the layer has been subsetted.

Parameters

force

true to update layer extent even if it's read from xml by default, false otherwise

Definition at line 977 of file qgsvectorlayer.cpp.

updateFeature()

bool QgsVectorLayer::updateFeature	(	QgsFeature &	feature,
		bool	skipDefaultValues = false
	)

Updates an existing feature in the layer, replacing the attributes and geometry for the feature with matching QgsFeature::id() with the attributes and geometry from feature.

Changes are not immediately committed to the layer.

If skipDefaultValue is set to true, default field values will not be updated. This can be used to override default field value expressions.

Returns true if the feature's attribute was successfully changed.

Note

Calls to updateFeature() are only valid for layers in which edits have been enabled by a call to startEditing(). Changes made to features using this method are not committed to the underlying data provider until a commitChanges() call is made. Any uncommitted changes can be discarded by calling rollBack().

Warning

This method needs to query the underlying data provider to fetch the feature with matching QgsFeature::id() on every call. Depending on the underlying data source this can be slow to execute. Consider using the more efficient changeAttributeValue() or changeGeometry() methods instead.

See also

startEditing()

commitChanges()

changeGeometry()

changeAttributeValue()

Definition at line 1355 of file qgsvectorlayer.cpp.

updateFields()

void QgsVectorLayer::updateFields

(

)

Will regenerate the fields property of this layer by obtaining all fields from the dataProvider, joined fields and virtual fields.

It will also take any changes made to default values into consideration.

Note

Unless the fields on the provider have directly been modified, there is no reason to call this method.

Definition at line 4400 of file qgsvectorlayer.cpp.

vectorJoins()

const QList< QgsVectorLayerJoinInfo > QgsVectorLayer::vectorJoins

(

)

const

Definition at line 4348 of file qgsvectorlayer.cpp.

vectorLayerTypeFlags()

Qgis::VectorLayerTypeFlags QgsVectorLayer::vectorLayerTypeFlags

(

)

const

Returns the vector layer type flags.

See also

isSqlQuery()

Since

QGIS 3.24

Definition at line 423 of file qgsvectorlayer.cpp.

weakRelations()

QList< QgsWeakRelation > QgsVectorLayer::weakRelations

(

)

const

Returns the layer's weak relations as specified in the layer's style.

Returns

A list of weak relations

Note

not available in Python bindings

See also

setWeakRelations()

Since

QGIS 3.12

Definition at line 5914 of file qgsvectorlayer.cpp.

wkbType()

Qgis::WkbType QgsVectorLayer::wkbType ( ) const

virtual

Returns the WKBType or WKBUnknown in case of error.

Implements QgsFeatureSource.

Definition at line 822 of file qgsvectorlayer.cpp.

writeCustomSymbology

void QgsVectorLayer::writeCustomSymbology ( QDomElement &  element, QDomDocument &  doc, QString &  errorMessage  ) const

signal

Signal emitted whenever the symbology (QML-file) for this layer is being written.

If there is custom style information you want to save to the file, you can connect to this signal and update the element accordingly.

Parameters

element	The XML element where you can add additional style information to.
doc	The XML document that you can use to create new XML nodes.
errorMessage	Write error messages into this string.

writeSld()

bool QgsVectorLayer::writeSld	(	QDomNode &	node,
		QDomDocument &	doc,
		QString &	errorMessage,
		const QVariantMap &	props = QVariantMap()
	)		const

Writes the symbology of the layer into the document provided in SLD 1.1 format.

Parameters

node	the node that will have the style element added to it.
doc	the document that will have the QDomNode added.
errorMessage	reference to string that will be updated with any error messages
props	a open ended set of properties that can drive/inform the SLD encoding

Returns

true in case of success

Definition at line 3279 of file qgsvectorlayer.cpp.

writeStyle()

bool QgsVectorLayer::writeStyle	(	QDomNode &	node,
		QDomDocument &	doc,
		QString &	errorMessage,
		const QgsReadWriteContext &	context,
		QgsMapLayer::StyleCategories	categories = QgsMapLayer::AllStyleCategories
	)		const

Definition at line 3155 of file qgsvectorlayer.cpp.

writeSymbology()

bool QgsVectorLayer::writeSymbology	(	QDomNode &	node,
		QDomDocument &	doc,
		QString &	errorMessage,
		const QgsReadWriteContext &	context,
		QgsMapLayer::StyleCategories	categories = QgsMapLayer::AllStyleCategories
	)		const

Definition at line 2943 of file qgsvectorlayer.cpp.

writeXml()

bool QgsVectorLayer::writeXml ( QDomNode &  layer_node, QDomDocument &  doc, const QgsReadWriteContext &  context  ) const

virtual

Writes vector layer specific state to project file Dom node.

Note

Called by QgsMapLayer::writeXml().

Reimplemented from QgsMapLayer.

Definition at line 2292 of file qgsvectorlayer.cpp.

Friends And Related Symbol Documentation

QgsVectorLayerEditBuffer

friend class QgsVectorLayerEditBuffer

friend

Definition at line 2916 of file qgsvectorlayer.h.

QgsVectorLayerEditBufferGroup

friend class QgsVectorLayerEditBufferGroup

friend

Definition at line 2917 of file qgsvectorlayer.h.

QgsVectorLayerEditPassthrough

friend class QgsVectorLayerEditPassthrough

friend

Definition at line 2918 of file qgsvectorlayer.h.

QgsVectorLayerFeatureSource

friend class QgsVectorLayerFeatureSource

friend

Definition at line 2975 of file qgsvectorlayer.h.

Member Data Documentation

settingsSimplifyAlgorithm

const QgsSettingsEntryEnumFlag< QgsVectorSimplifyMethod::SimplifyAlgorithm > * QgsVectorLayer::settingsSimplifyAlgorithm = new QgsSettingsEntryEnumFlag<QgsVectorSimplifyMethod::SimplifyAlgorithm>( QStringLiteral( "simplifyAlgorithm" ), QgsSettingsTree::sTreeQgis, QgsVectorSimplifyMethod::SimplifyAlgorithm::Distance )

static

Definition at line 415 of file qgsvectorlayer.h.

settingsSimplifyDrawingHints

const QgsSettingsEntryEnumFlag< QgsVectorSimplifyMethod::SimplifyHints > * QgsVectorLayer::settingsSimplifyDrawingHints = new QgsSettingsEntryEnumFlag<QgsVectorSimplifyMethod::SimplifyHints>( QStringLiteral( "simplifyDrawingHints" ), QgsSettingsTree::sTreeQgis, QgsVectorSimplifyMethod::SimplifyHint::NoSimplification )

static

Definition at line 416 of file qgsvectorlayer.h.

settingsSimplifyDrawingTol

const QgsSettingsEntryDouble * QgsVectorLayer::settingsSimplifyDrawingTol = new QgsSettingsEntryDouble( QStringLiteral( "simplifyDrawingTol" ), QgsSettingsTree::sTreeQgis, Qgis::DEFAULT_MAPTOPIXEL_THRESHOLD )

static

Definition at line 414 of file qgsvectorlayer.h.

settingsSimplifyLocal

const QgsSettingsEntryBool * QgsVectorLayer::settingsSimplifyLocal = new QgsSettingsEntryBool( QStringLiteral( "simplifyLocal" ), QgsSettingsTree::sTreeQgis, true )

static

Definition at line 411 of file qgsvectorlayer.h.

settingsSimplifyMaxScale

const QgsSettingsEntryDouble * QgsVectorLayer::settingsSimplifyMaxScale = new QgsSettingsEntryDouble( QStringLiteral( "simplifyMaxScale" ), QgsSettingsTree::sTreeQgis, 1.0 )

static

Definition at line 413 of file qgsvectorlayer.h.

Property Documentation

displayExpression

QString QgsVectorLayer::displayExpression

readwrite

Definition at line 404 of file qgsvectorlayer.h.

editFormConfig

QgsEditFormConfig QgsVectorLayer::editFormConfig

readwrite

Definition at line 405 of file qgsvectorlayer.h.

readOnly

bool QgsVectorLayer::readOnly

readwrite

Definition at line 406 of file qgsvectorlayer.h.

subsetString

QString QgsVectorLayer::subsetString

readwrite

Definition at line 403 of file qgsvectorlayer.h.

supportsEditing

bool QgsVectorLayer::supportsEditing

read

Definition at line 407 of file qgsvectorlayer.h.

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The documentation for this class was generated from the following files:

• /build/qgis-3.36.0+99sid/src/core/vector/qgsvectorlayer.h
• /build/qgis-3.36.0+99sid/src/core/vector/qgsvectorlayer.cpp