QgsVectorLayer Class Reference

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

#include <qgsvectorlayer.h>

Inheritance diagram for QgsVectorLayer:

Classes
struct	LayerOptions
	Setting options for loading vector layers. More...

Public Types
enum	EditResult {   Success = 0, EmptyGeometry = 1, EditFailed = 2, FetchFeatureFailed = 3,   InvalidLayer = 4 }
	Result of an edit operation. More...
enum	SelectBehavior { SetSelection, AddToSelection, IntersectSelection, RemoveFromSelection }
	Selection behavior. More...
enum	VertexMarkerType { SemiTransparentCircle, Cross, NoMarker }
	Editing vertex markers. More...
Public Types inherited from QgsMapLayer
enum	LayerType { VectorLayer, RasterLayer, PluginLayer }
	Types of layers that can be added to a map. More...
enum	PropertyType { Style = 0, Metadata }
	Maplayer has a style and a metadata property. More...
Public Types inherited from QgsFeatureSink
enum	Flag { FastInsert = 1 << 1 }
	Flags controlling how features are added to a sink. More...

Public Slots
void	deselect (const QgsFeatureId featureId)
	Deselect feature by its ID. More...
void	deselect (const QgsFeatureIds &featureIds)
	Deselect features by their ID. More...
void	removeSelection ()
	Clear selection. More...
void	select (QgsFeatureId featureId)
	Select feature by its ID. More...
void	select (const QgsFeatureIds &featureIds)
	Select features by their ID. More...
bool	startEditing ()
	Makes the layer editable. More...
virtual void	updateExtents (bool force=false)
	Update the extents for the layer. More...
Public Slots inherited from QgsMapLayer
void	emitStyleChanged ()
	Triggers an emission of the styleChanged() signal. More...
void	setMaximumScale (double scale)
	Sets the maximum map scale (i.e. More...
void	setMinimumScale (double scale)
	Sets the minimum map scale (i.e. More...
void	setRefreshOnNofifyMessage (const QString &message)
	Set the notification message that triggers repaine If refresh on notification is enabled, the notification will triggerRepaint only if the notification message is equal to. More...
void	setRefreshOnNotifyEnabled (bool enabled)
	Set whether provider notification is connected to triggerRepaint. More...
void	setScaleBasedVisibility (const bool enabled)
	Sets whether scale based visibility is enabled for the layer. More...
void	triggerRepaint (bool deferredUpdate=false)
	Will advise the map canvas (and any other interested party) that this layer requires to be repainted. More...

Signals
void	attributeAdded (int idx)
	Will be emitted, when a new attribute has been added to this vector layer. More...
void	attributeDeleted (int idx)
	Will be emitted, when an attribute has been deleted from this vector layer. More...
void	attributeValueChanged (QgsFeatureId fid, int idx, const QVariant &value)
	Is emitted whenever an attribute value change is done in the edit buffer. More...
void	beforeAddingExpressionField (const QString &fieldName)
	Will be emitted, when an expression field is going to be added to this vector layer. More...
void	beforeCommitChanges ()
	Is emitted, before changes are committed to the data provider. More...
void	beforeEditingStarted ()
	Is emitted, before editing on this layer is started. More...
void	beforeModifiedCheck () const
	Is emitted, when layer is checked for modifications. Use for last-minute additions. More...
void	beforeRemovingExpressionField (int idx)
	Will be emitted, when an expression field is going to be deleted from this vector layer. More...
void	beforeRollBack ()
	Is emitted, before changes are rolled back. More...
void	committedAttributesAdded (const QString &layerId, const QList< QgsField > &addedAttributes)
	This signal is emitted, when attributes are added to the provider. More...
void	committedAttributesDeleted (const QString &layerId, const QgsAttributeList &deletedAttributes)
	This signal is emitted, when attributes are deleted from the provider. More...
void	committedAttributeValuesChanges (const QString &layerId, const QgsChangedAttributesMap &changedAttributesValues)
	This signal is emitted, when attribute value changes are saved to the provider. More...
void	committedFeaturesAdded (const QString &layerId, const QgsFeatureList &addedFeatures)
	This signal is emitted, when features are added to the provider. More...
void	committedFeaturesRemoved (const QString &layerId, const QgsFeatureIds &deletedFeatureIds)
	This signal is emitted, when features are deleted from the provider. More...
void	committedGeometriesChanges (const QString &layerId, const QgsGeometryMap &changedGeometries)
	This signal is emitted, when geometry changes are saved to the provider. More...
void	displayExpressionChanged ()
	Emitted when the display expression changes. More...
void	editCommandDestroyed ()
	Signal emitted, whan an edit command is destroyed. More...
void	editCommandEnded ()
	Signal emitted, when an edit command successfully ended. More...
void	editCommandStarted (const QString &text)
	Signal emitted when a new edit command has been started. More...
void	editFormConfigChanged ()
	Will be emitted whenever the edit form configuration of this layer changes. More...
void	editingStarted ()
	Is emitted, when editing on this layer has started. More...
void	editingStopped ()
	Is emitted, when edited changes successfully have been written to the data provider. More...
void	featureAdded (QgsFeatureId fid)
	Emitted when a new feature has been added to the layer. More...
void	featureBlendModeChanged (QPainter::CompositionMode blendMode)
	Signal emitted when setFeatureBlendMode() is called. More...
void	featureDeleted (QgsFeatureId fid)
	Emitted when a feature has been deleted. More...
void	featuresDeleted (const QgsFeatureIds &fids)
	Emitted when features have been deleted. More...
void	geometryChanged (QgsFeatureId fid, const QgsGeometry &geometry)
	Is emitted whenever a geometry change is done in the edit buffer. More...
void	labelingFontNotFound (QgsVectorLayer *layer, const QString &fontfamily)
	Emitted when the font family defined for labeling layer is not found on system. More...
void	layerModified ()
	This signal is emitted when modifications has been done on layer. More...
void	mapTipTemplateChanged ()
	Emitted when the map tip changes. More...
void	opacityChanged (double opacity)
	Emitted when the layer's opacity is changed, where opacity is a value between 0 (transparent) and 1 (opaque). More...
void	raiseError (const QString &msg)
	Signals an error related to this vector layer. More...
void	readCustomSymbology (const QDomElement &element, QString &errorMessage)
	Signal emitted whenever the symbology (QML-file) for this layer is being read. More...
void	readOnlyChanged ()
	Emitted when the read only state of this layer is changed. More...
void	selectionChanged (const QgsFeatureIds &selected, const QgsFeatureIds &deselected, const bool clearAndSelect)
	This signal is emitted when selection was changed. More...
void	symbolFeatureCountMapChanged ()
	Emitted when the feature count for symbols on this layer has been recalculated. More...
void	updatedFields ()
	Is emitted, whenever the fields available from this layer have been changed. More...
void	writeCustomSymbology (QDomElement &element, QDomDocument &doc, QString &errorMessage) const
	Signal emitted whenever the symbology (QML-file) for this layer is being written. More...
Signals inherited from QgsMapLayer
void	autoRefreshIntervalChanged (int interval)
	Emitted when the auto refresh interval changes. More...
void	blendModeChanged (QPainter::CompositionMode blendMode)
	Signal emitted when the blend mode is changed, through QgsMapLayer::setBlendMode() More...
void	configChanged ()
	Emitted whenever the configuration is changed. More...
void	crsChanged ()
	Emit a signal that layer's CRS has been reset. More...
void	dataChanged ()
	Data of layer changed. More...
void	dependenciesChanged ()
	Emitted when dependencies are changed. More...
void	legendChanged ()
	Signal emitted when legend of the layer has changed. More...
void	metadataChanged ()
	Emitted when the layer's metadata is changed. More...
void	nameChanged ()
	Emitted when the name has been changed. More...
void	recalculateExtents () const
	This is used to send a request that any mapcanvas using this layer update its extents. More...
void	renderer3DChanged ()
	Signal emitted when 3D renderer associated with the layer has changed. More...
void	rendererChanged ()
	Signal emitted when renderer is changed. More...
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. More...
void	statusChanged (const QString &status)
	Emit a signal with status (e.g. to be caught by QgisApp and display a msg on status bar) More...
void	styleChanged ()
	Signal emitted whenever a change affects the layer's style. More...
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. More...

Public Member Functions
	QgsVectorLayer (const QString &path=QString(), const QString &baseName=QString(), const QString &providerLib="ogr", const QgsVectorLayer::LayerOptions &options=QgsVectorLayer::LayerOptions())
	Constructor - creates a vector layer. More...
	QgsVectorLayer (const QgsVectorLayer &rhs)=delete
	QgsVectorLayer cannot be copied. More...
	~QgsVectorLayer () override
QgsActionManager *	actions ()
	Get all layer actions defined on this layer. More...
const QgsActionManager *	actions () const
	Get all layer actions defined on this layer. More...
bool	addAttribute (const QgsField &field)
	Add an attribute field (but does not commit it) returns true if the field was added. More...
int	addExpressionField (const QString &exp, const QgsField &fld)
	Add a new field which is calculated by the expression specified. More...
bool	addFeature (QgsFeature &feature, QgsFeatureSink::Flags flags=nullptr) override
	Adds a single feature to the sink. More...
bool	addFeatures (QgsFeatureList &features, QgsFeatureSink::Flags flags=nullptr) override
	Adds a list of features to the sink. More...
bool	addJoin (const QgsVectorLayerJoinInfo &joinInfo)
	Joins another vector layer to this layer. More...
QgsGeometry::OperationResult	addPart (const QList< QgsPointXY > &ring)
	Adds a new part polygon to a multipart feature. More...
QgsGeometry::OperationResult	addPart (const QgsPointSequence &ring)
	Adds a new part polygon to a multipart feature. More...
QgsGeometry::OperationResult	addPart (QgsCurve *ring)
QgsGeometry::OperationResult	addRing (const QVector< QgsPointXY > &ring, QgsFeatureId *featureId=nullptr)
	Adds a ring to polygon/multipolygon features. More...
QgsGeometry::OperationResult	addRing (QgsCurve *ring, QgsFeatureId *featureId=nullptr)
	Adds a ring to polygon/multipolygon features (takes ownership) More...
int	addTopologicalPoints (const QgsGeometry &geom)
	Adds topological points for every vertex of the geometry. More...
int	addTopologicalPoints (const QgsPointXY &p)
	Adds a vertex to segments which intersect point p but don't already have a vertex there. More...
QVariant	aggregate (QgsAggregateCalculator::Aggregate aggregate, const QString &fieldOrExpression, const QgsAggregateCalculator::AggregateParameters &parameters=QgsAggregateCalculator::AggregateParameters(), QgsExpressionContext *context=nullptr, bool *ok=nullptr) const
	Calculates an aggregated value from the layer's features. More...
QString	attributeAlias (int index) const
	Returns the alias of an attribute name or a null string if there is no alias. More...
QgsStringMap	attributeAliases () const
	Returns a map of field name to attribute alias. More...
QString	attributeDisplayName (int index) const
	Convenience function that returns the attribute alias if defined or the field name else. More...
QgsAttributeList	attributeList () const
	Returns list of attribute indexes. More...
QgsAttributeTableConfig	attributeTableConfig () const
	Get the attribute table configuration object. More...
QgsAuxiliaryLayer *	auxiliaryLayer ()
	Returns the current auxiliary layer. More...
const QgsAuxiliaryLayer *	auxiliaryLayer () const
	Returns the current const auxiliary layer. More...
void	beginEditCommand (const QString &text)
	Create edit command for undo/redo operations. More...
QgsRectangle	boundingBoxOfSelected () const
	Returns the bounding box of the selected features. If there is no selection, QgsRectangle(0,0,0,0) is returned. More...
QString	capabilitiesString () const
	Capabilities for this layer, comma separated and translated. More...
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). More...
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). More...
bool	changeGeometry (QgsFeatureId fid, const QgsGeometry &geometry, bool skipDefaultValue=false)
	Changes a feature's geometry within the layer's edit buffer (but does not immediately commit the changes). More...
QgsVectorLayer *	clone () const override
	Returns a new instance equivalent to this one. More...
bool	commitChanges ()
	Attempts to commit to the underlying data provider any buffered changes made since the last to call to startEditing(). More...
QStringList	commitErrors () const
	Returns a list containing any error messages generated when attempting to commit changes to the layer. More...
QgsConditionalLayerStyles *	conditionalStyles () const
	Return the conditional styles that are set for this layer. More...
QString	constraintDescription (int index) const
	Returns the descriptive name for the constraint expression for a specified field index. More...
QString	constraintExpression (int index) const
	Returns the constraint expression for for a specified field index, if set. More...
QgsVectorLayerFeatureCounter *	countSymbolFeatures ()
	Count features for symbols. More...
QgsExpressionContext	createExpressionContext () const override
	This method needs to be reimplemented in all classes which implement this interface and return an expression context. More...
QgsExpressionContextScope *	createExpressionContextScope () const override
	This method needs to be reimplemented in all classes which implement this interface and return an expression context scope. More...
QgsMapLayerRenderer *	createMapRenderer (QgsRenderContext &rendererContext) override
	Return new instance of QgsMapLayerRenderer that will be used for rendering of given context. More...
QString	dataComment () const
	Returns a description for this layer as defined in the data provider. More...
QgsVectorDataProvider *	dataProvider () override
	Returns the layer's data provider. More...
const QgsVectorDataProvider *	dataProvider () const override
	Returns the layer's data provider in a const-correct manner. More...
QVariant	defaultValue (int index, const QgsFeature &feature=QgsFeature(), QgsExpressionContext *context=nullptr) const
	Returns the calculated default value for the specified field index. More...
QgsDefaultValue	defaultValueDefinition (int index) const
	Returns the definition of the expression used when calculating the default value for a field. More...
virtual bool	deleteAttribute (int attr)
	Deletes an attribute field (but does not commit it). More...
bool	deleteAttributes (QList< int > attrs)
	Deletes a list of attribute fields (but does not commit it) More...
bool	deleteFeature (QgsFeatureId fid)
	Deletes a feature from the layer (but does not commit it). More...
bool	deleteFeatures (const QgsFeatureIds &fids)
	Deletes a set of features from the layer (but does not commit it) More...
bool	deleteSelectedFeatures (int *deletedCount=nullptr)
	Deletes the selected features. More...
virtual bool	deleteStyleFromDatabase (const QString &styleId, QString &msgError)
	Delete a style from the database. More...
EditResult	deleteVertex (QgsFeatureId featureId, int vertex)
	Deletes a vertex from a feature. More...
QSet< QgsMapLayerDependency >	dependencies () const override
	Gets the list of dependencies. More...
void	destroyEditCommand ()
	Destroy active command and reverts all changes in it. More...
const QgsDiagramLayerSettings *	diagramLayerSettings () const
const QgsDiagramRenderer *	diagramRenderer () const
bool	diagramsEnabled () const
	Returns whether the layer contains diagrams which are enabled and should be drawn. More...
QString	displayExpression () const
	Get the preview expression, used to create a human readable preview string. More...
QString	displayField () const
	This is a shorthand for accessing the displayExpression if it is a simple field. More...
QgsVectorLayerEditBuffer *	editBuffer ()
	Buffer with uncommitted editing operations. Only valid after editing has been turned on. More...
const QgsVectorLayerEditBuffer *	editBuffer () const
	Buffer with uncommitted editing operations. More...
QgsEditFormConfig	editFormConfig () const
	Get the configuration of the form used to represent this vector layer. More...
QgsEditorWidgetSetup	editorWidgetSetup (int index) const
	The editor widget setup defines which QgsFieldFormatter and editor widget will be used for the field at index. More...
void	endEditCommand ()
	Finish edit command and add it to undo/redo stack. More...
QSet< QString >	excludeAttributesWfs () const
	A set of attributes that are not advertised in WFS requests with QGIS server. More...
QSet< QString >	excludeAttributesWms () const
	A set of attributes that are not advertised in WMS requests with QGIS server. More...
QString	expressionField (int index) const
	Returns the expression used for a given expression field. More...
QgsRectangle	extent () const override
	Returns the extent of the layer. More...
QPainter::CompositionMode	featureBlendMode () const
	Returns the current blending mode for features. More...
long	featureCount (const QString &legendKey) const
	Number of features rendered with specified legend key. More...
long	featureCount () const override
	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. More...
QgsFieldConstraints::Constraints	fieldConstraints (int fieldIndex) const
	Returns any constraints which are present for a specified field index. More...
QMap< QgsFieldConstraints::Constraint, QgsFieldConstraints::ConstraintStrength >	fieldConstraintsAndStrength (int fieldIndex) const
	Returns a map of constraint with their strength for a specific field of the layer. More...
QgsFields	fields () const override
	Returns the list of fields of this layer. More...
QgsWkbTypes::GeometryType	geometryType () const
	Returns point, line or polygon. More...
QgsFeature	getFeature (QgsFeatureId fid) const
	Query the layer for the feature with the given id. More...
QgsFeatureIterator	getFeatures (const QgsFeatureRequest &request=QgsFeatureRequest()) const override
	Query the layer for features specified in request. More...
QgsFeatureIterator	getFeatures (const QString &expression)
	Query the layer for features matching a given expression. More...
QgsFeatureIterator	getFeatures (const QgsFeatureIds &fids)
	Query the layer for the features with the given ids. More...
QgsFeatureIterator	getFeatures (const QgsRectangle &rectangle)
	Query the layer for the features which intersect the specified rectangle. More...
QgsFeatureIterator	getSelectedFeatures (QgsFeatureRequest request=QgsFeatureRequest()) const
	Get an iterator of the selected features. More...
virtual QString	getStyleFromDatabase (const QString &styleId, QString &msgError)
	Will return the named style corresponding to style id provided. More...
QString	htmlMetadata () const override
	Obtain a formatted HTML string containing assorted metadata for this layer. More...
bool	insertVertex (double x, double y, QgsFeatureId atFeatureId, int beforeVertex)
	Insert 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. More...
bool	insertVertex (const QgsPoint &point, QgsFeatureId atFeatureId, int beforeVertex)
	Insert 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. More...
void	invertSelection ()
	Select not selected features and deselect selected ones. More...
void	invertSelectionInRectangle (QgsRectangle &rect)
	Invert selection of features found within the search rectangle (in layer's coordinates) More...
bool	isAuxiliaryField (int index, int &srcIndex) const
	Returns true if the field comes from the auxiliary layer, false otherwise. More...
bool	isEditable () const override
	Returns true if the provider is in editing mode. More...
bool	isEditCommandActive () const
	Test if an edit command is active. More...
virtual bool	isModified () const
	Returns true if the provider has been modified since the last commit. More...
bool	isSpatial () const override
	Returns true if this is a geometry layer and false in case of NoGeometry (table only) or UnknownGeometry. More...
QgsVectorLayerJoinBuffer *	joinBuffer ()
	Accessor to the join buffer object. More...
const QgsAbstractVectorLayerLabeling *	labeling () const
	Access to const labeling configuration. More...
QgsAbstractVectorLayerLabeling *	labeling ()
	Access to labeling configuration. More...
bool	labelsEnabled () const
	Returns whether the layer contains labels which are enabled and should be drawn. More...
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. More...
bool	loadAuxiliaryLayer (const QgsAuxiliaryStorage &storage, const QString &key=QString())
	Loads the auxiliary layer for this vector layer. More...
virtual QString	loadNamedStyle (const QString &theURI, bool &resultFlag, bool loadFromLocalDb)
	Load a named style from file/local db/datasource db. More...
QString	loadNamedStyle (const QString &theURI, bool &resultFlag) override
	Calls loadNamedStyle( theURI, resultFlag, false ); Retained for backward compatibility. More...
QString	mapTipTemplate () const
	The mapTip is a pretty, html representation for feature information. More...
QVariant	maximumValue (int index) const override
	Returns the maximum value for an attribute column or an invalid variant in case of error. More...
QVariant	minimumValue (int index) const override
	Returns the minimum value for an attribute column or an invalid variant in case of error. More...
void	modifySelection (const QgsFeatureIds &selectIds, const QgsFeatureIds &deselectIds)
	Modifies the current selection on this layer. More...
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. More...
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. More...
double	opacity () const
	Returns the opacity for the vector layer, where opacity is a value between 0 (totally transparent) and 1.0 (fully opaque). More...
QgsVectorLayer &	operator= (QgsVectorLayer const &rhs)=delete
	QgsVectorLayer cannot be copied. More...
QgsAttributeList	primaryKeyAttributes () const
	Returns the list of attributes which make up the layer's primary keys. More...
QString	providerType () const
	Return the provider type for this layer. More...
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. More...
bool	readSld (const QDomNode &node, QString &errorMessage) override
bool	readStyle (const QDomNode &node, QString &errorMessage, const QgsReadWriteContext &context) override
	Read the style for the current layer from the Dom node supplied. More...
bool	readSymbology (const QDomNode &layerNode, QString &errorMessage, const QgsReadWriteContext &context) override
	Read the symbology for the current layer from the Dom node supplied. More...
bool	readXml (const QDomNode &layer_node, const QgsReadWriteContext &context) override
	Reads vector layer specific state from project file Dom node. More...
QList< QgsRelation >	referencingRelations (int idx) const
	Get relations, where the foreign key is on this layer. More...
void	reload () override
	Synchronises with changes in the datasource. More...
void	removeExpressionField (int index)
	Remove an expression field. More...
void	removeFieldAlias (int index)
	Removes an alias (a display name) for attributes to display in dialogs. More...
void	removeFieldConstraint (int index, QgsFieldConstraints::Constraint constraint)
	Removes a constraint for a specified field index. More...
bool	removeJoin (const QString &joinLayerId)
	Removes a vector layer join. More...
bool	renameAttribute (int index, const QString &newName)
	Renames an attribute field (but does not commit it). More...
QgsFeatureRenderer *	renderer ()
	Return renderer. More...
const QgsFeatureRenderer *	renderer () const
	Return const renderer. More...
void	resolveReferences (QgsProject *project) override
	Resolve references to other layers (kept as layer IDs after reading XML) into layer objects. More...
bool	rollBack (bool deleteBuffer=true)
	Stops a current editing operation and discards any uncommitted edits. More...
virtual void	saveStyleToDatabase (const QString &name, const QString &description, bool useAsDefault, const QString &uiFileContent, QString &msgError)
	Save named and sld style of the layer to the style table in the db. More...
void	selectAll ()
	Select all the features. More...
void	selectByExpression (const QString &expression, SelectBehavior behavior=SetSelection)
	Select matching features using an expression. More...
void	selectByIds (const QgsFeatureIds &ids, SelectBehavior behavior=SetSelection)
	Select matching features using a list of feature IDs. More...
void	selectByRect (QgsRectangle &rect, SelectBehavior behavior=SetSelection)
	Select features found within the search rectangle (in layer's coordinates) More...
int	selectedFeatureCount () const
	The number of features that are selected in this layer. More...
const QgsFeatureIds &	selectedFeatureIds () const
	Return reference to identifiers of selected features. More...
QgsFeatureList	selectedFeatures () const
	Get a copy of the user-selected features. More...
void	setAttributeTableConfig (const QgsAttributeTableConfig &attributeTableConfig)
	Set the attribute table configuration object. More...
void	setAuxiliaryLayer (QgsAuxiliaryLayer *layer=nullptr)
	Sets the current auxiliary layer. More...
void	setConstraintExpression (int index, const QString &expression, const QString &description=QString())
	Set the constraint expression for the specified field index. More...
void	setCoordinateSystem ()
	Setup the coordinate system transformation for the layer. More...
void	setDataSource (const QString &dataSource, const QString &baseName, const QString &provider, bool loadDefaultStyleFlag=false)
	Update the data source of the layer. More...
void	setDefaultValueDefinition (int index, const QgsDefaultValue &definition)
	Sets the definition of the expression to use when calculating the default value for a field. More...
bool	setDependencies (const QSet< QgsMapLayerDependency > &layers) override
	Sets the list of dependencies. More...
void	setDiagramLayerSettings (const QgsDiagramLayerSettings &s)
void	setDiagramRenderer (QgsDiagramRenderer *r)
	Sets diagram rendering object (takes ownership) More...
void	setDisplayExpression (const QString &displayExpression)
	Set the preview expression, used to create a human readable preview string. More...
void	setEditFormConfig (const QgsEditFormConfig &editFormConfig)
	Get the configuration of the form used to represent this vector layer. More...
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. More...
void	setExcludeAttributesWfs (const QSet< QString > &att)
	A set of attributes that are not advertised in WFS requests with QGIS server. More...
void	setExcludeAttributesWms (const QSet< QString > &att)
	A set of attributes that are not advertised in WMS requests with QGIS server. More...
void	setFeatureBlendMode (QPainter::CompositionMode blendMode)
	Set the blending mode used for rendering each feature. More...
void	setFieldAlias (int index, const QString &aliasString)
	Sets an alias (a display name) for attributes to display in dialogs. More...
void	setFieldConstraint (int index, QgsFieldConstraints::Constraint constraint, QgsFieldConstraints::ConstraintStrength strength=QgsFieldConstraints::ConstraintStrengthHard)
	Sets a constraint for a specified field index. More...
void	setLabeling (QgsAbstractVectorLayerLabeling *labeling)
	Set labeling configuration. More...
void	setLabelsEnabled (bool enabled)
	Sets whether labels should be enabled for the layer. More...
void	setMapTipTemplate (const QString &mapTipTemplate)
	The mapTip is a pretty, html representation for feature information. More...
void	setOpacity (double opacity)
	Sets the opacity for the vector layer, where opacity is a value between 0 (totally transparent) and 1.0 (fully opaque). More...
void	setProviderEncoding (const QString &encoding)
	Sets the textencoding of the data provider. More...
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. More...
bool	setReadOnly (bool readonly=true)
	Make layer read-only (editing disabled) or not. More...
void	setRenderer (QgsFeatureRenderer *r)
	Set renderer which will be invoked to represent this layer. More...
void	setSimplifyMethod (const QgsVectorSimplifyMethod &simplifyMethod)
	Set the simplification settings for fast rendering of features. More...
virtual bool	setSubsetString (const QString &subset)
	Set the string (typically sql) used to define a subset of the layer. More...
bool	simplifyDrawingCanbeApplied (const QgsRenderContext &renderContext, QgsVectorSimplifyMethod::SimplifyHint simplifyHint) const
	Returns whether the VectorLayer can apply the specified simplification hint. More...
const QgsVectorSimplifyMethod &	simplifyMethod () const
	Returns the simplification settings for fast rendering of features. More...
QgsCoordinateReferenceSystem	sourceCrs () const override
	Returns the coordinate reference system for features in the source. More...
QgsRectangle	sourceExtent () const override
	Returns the extent of all geometries from the source. More...
QString	sourceName () const override
	Returns a friendly display name for the source. More...
QgsGeometry::OperationResult	splitFeatures (const QVector< QgsPointXY > &splitLine, bool topologicalEditing=false)
	Splits features cut by the given line. More...
QgsGeometry::OperationResult	splitParts (const QVector< QgsPointXY > &splitLine, bool topologicalEditing=false)
	Splits parts cut by the given line. More...
QString	storageType () const
	Returns the permanent storage type for this layer as a friendly name. More...
virtual QString	subsetString () const
	Get the string (typically sql) used to define a subset of the layer. More...
int	translateFeature (QgsFeatureId featureId, double dx, double dy)
	Translates feature by dx, dy. More...
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. More...
QSet< QVariant >	uniqueValues (int fieldIndex, int limit=-1) const override
	Calculates a list of unique values contained within an attribute in the layer. More...
void	updateExpressionField (int index, const QString &exp)
	Changes the expression used to define an expression based (virtual) field. More...
bool	updateFeature (const 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. More...
void	updateFields ()
	Will regenerate the fields property of this layer by obtaining all fields from the dataProvider, joined fields and virtual fields. More...
const QList< QgsVectorLayerJoinInfo >	vectorJoins () const
QgsWkbTypes::Type	wkbType () const override
	Returns the WKBType or WKBUnknown in case of error. More...
bool	writeSld (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsStringMap &props=QgsStringMap()) const
	Writes the symbology of the layer into the document provided in SLD 1.1 format. More...
bool	writeStyle (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &context) const override
	Write just the style information for the layer into the document. More...
bool	writeSymbology (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &context) const override
	Write the symbology for the layer into the docment provided. More...
bool	writeXml (QDomNode &layer_node, QDomDocument &doc, const QgsReadWriteContext &context) const override
	Write vector layer specific state to project file Dom node. More...
Public Member Functions inherited from QgsMapLayer
	QgsMapLayer (QgsMapLayer::LayerType type=VectorLayer, const QString &name=QString(), const QString &source=QString())
	Constructor for QgsMapLayer. More...
	QgsMapLayer (QgsMapLayer const &)=delete
	QgsMapLayer cannot be copied. More...
	~QgsMapLayer () override
QString	abstract () const
	Returns the abstract of the layer used by QGIS Server in GetCapabilities request. More...
QString	attribution () const
	Returns the attribution of the layer used by QGIS Server in GetCapabilities request. More...
QString	attributionUrl () const
	Returns the attribution URL of the layer used by QGIS Server in GetCapabilities request. More...
int	autoRefreshInterval () const
	Returns the auto refresh interval (in milliseconds). More...
QPainter::CompositionMode	blendMode () const
	Returns the current blending mode for a layer. More...
QgsCoordinateReferenceSystem	crs () const
	Returns the layer's spatial reference system. More...
QVariant	customProperty (const QString &value, const QVariant &defaultValue=QVariant()) const
	Read a custom property from layer. More...
QStringList	customPropertyKeys () const
	Returns list of all keys within custom properties. More...
QString	dataUrl () const
	Returns the DataUrl of the layer used by QGIS Server in GetCapabilities request. More...
QString	dataUrlFormat () const
	Returns the DataUrl format of the layer used by QGIS Server in GetCapabilities request. More...
virtual QgsError	error () const
	Get current status error. More...
void	exportNamedMetadata (QDomDocument &doc, QString &errorMsg) const
	Export the current metadata of this layer as named metadata in a QDomDocument. More...
virtual void	exportNamedStyle (QDomDocument &doc, QString &errorMsg) const
	Export the properties of this layer as named style in a QDomDocument. More...
virtual void	exportSldStyle (QDomDocument &doc, QString &errorMsg) const
	Export the properties of this layer as SLD style in a QDomDocument. More...
bool	hasAutoRefreshEnabled () const
	Returns true if auto refresh is enabled for the layer. More...
bool	hasScaleBasedVisibility () const
	Returns whether scale based visibility is enabled for the layer. More...
QString	id () const
	Returns the layer's unique ID, which is used to access this layer from QgsProject. More...
bool	importNamedMetadata (QDomDocument &document, QString &errorMessage)
	Import the metadata of this layer from a QDomDocument. More...
virtual bool	importNamedStyle (QDomDocument &doc, QString &errorMsg)
	Import the properties of this layer from a QDomDocument. More...
bool	isInScaleRange (double scale) const
	Tests whether the layer should be visible at the specified scale. More...
bool	isRefreshOnNotifyEnabled () const
	Returns true if the refresh on provider nofification is enabled. More...
bool	isValid () const
	Return the status of the layer. More...
QString	keywordList () const
	Returns the keyword list of the layer used by QGIS Server in GetCapabilities request. More...
QgsMapLayerLegend *	legend () const
	Can be null. More...
QString	legendUrl () const
	Returns the URL for the layer's legend. More...
QString	legendUrlFormat () const
	Returns the format for a URL based layer legend. More...
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) More...
virtual QString	loadDefaultStyle (bool &resultFlag)
	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) More...
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) More...
bool	loadNamedMetadataFromDatabase (const QString &db, const QString &uri, QString &qmd)
	Retrieve a named metadata for this layer from a sqlite database. More...
virtual bool	loadNamedStyleFromDatabase (const QString &db, const QString &uri, QString &qml)
	Retrieve a named style for this layer from a sqlite database. More...
virtual QString	loadSldStyle (const QString &uri, bool &resultFlag)
	Attempts to style the layer using the formatting from an SLD type file. More...
double	maximumScale () const
	Returns the maximum map scale (i.e. More...
virtual const QgsLayerMetadata &	metadata () const
	Returns a reference to the layer's metadata store. More...
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) More...
QString	metadataUrl () const
	Returns the metadata URL of the layer used by QGIS Server in GetCapabilities request. More...
QString	metadataUrlFormat () const
	Returns the metadata format of the layer used by QGIS Server in GetCapabilities request. More...
QString	metadataUrlType () const
	Returns the metadata type of the layer used by QGIS Server in GetCapabilities request. More...
double	minimumScale () const
	Returns the minimum map scale (i.e. More...
QString	name () const
	Returns the display name of the layer. More...
QgsMapLayer &	operator= (QgsMapLayer const &)=delete
	QgsMapLayer cannot be copied. More...
QString	publicSource () const
	Gets a version of the internal layer definition that has sensitive bits removed (for example, the password). More...
bool	readLayerXml (const QDomElement &layerElement, const QgsReadWriteContext &context)
	Sets state from Dom document. More...
bool	readOnly () const
	Returns if this layer is read only. More...
QString	refreshOnNotifyMessage () const
	Returns the message that should be notified by the provider to triggerRepaint. More...
void	removeCustomProperty (const QString &key)
	Remove a custom property from layer. More...
QgsAbstract3DRenderer *	renderer3D () const
	Returns 3D renderer associated with the layer. More...
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) More...
virtual 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) More...
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) More...
virtual QString	saveNamedStyle (const QString &uri, bool &resultFlag)
	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) More...
virtual QString	saveSldStyle (const QString &uri, bool &resultFlag) const
	Saves the properties of this layer to an SLD format file. More...
void	setAbstract (const QString &abstract)
	Sets the abstract of the layer used by QGIS Server in GetCapabilities request. More...
void	setAttribution (const QString &attrib)
	Sets the attribution of the layer used by QGIS Server in GetCapabilities request. More...
void	setAttributionUrl (const QString &attribUrl)
	Sets the attribution URL of the layer used by QGIS Server in GetCapabilities request. More...
void	setAutoRefreshEnabled (bool enabled)
	Sets whether auto refresh is enabled for the layer. More...
void	setAutoRefreshInterval (int interval)
	Sets the auto refresh interval (in milliseconds) for the layer. More...
void	setBlendMode (QPainter::CompositionMode blendMode)
	Set the blending mode used for rendering a layer. More...
void	setCrs (const QgsCoordinateReferenceSystem &srs, bool emitSignal=true)
	Sets layer's spatial reference system. More...
void	setCustomProperties (const QgsObjectCustomProperties &properties)
	Set custom properties for layer. More...
void	setCustomProperty (const QString &key, const QVariant &value)
	Set a custom property for layer. More...
void	setDataUrl (const QString &dataUrl)
	Sets the DataUrl of the layer used by QGIS Server in GetCapabilities request. More...
void	setDataUrlFormat (const QString &dataUrlFormat)
	Sets the DataUrl format of the layer used by QGIS Server in GetCapabilities request. More...
void	setKeywordList (const QString &keywords)
	Sets the keyword list of the layer used by QGIS Server in GetCapabilities request. More...
virtual void	setLayerOrder (const QStringList &layers)
	Reorders the previously selected sublayers of this layer from bottom to top. More...
void	setLegend (QgsMapLayerLegend *legend)
	Assign a legend controller to the map layer. More...
void	setLegendUrl (const QString &legendUrl)
	Sets the URL for the layer's legend. More...
void	setLegendUrlFormat (const QString &legendUrlFormat)
	Sets the format for a URL based layer legend. More...
virtual void	setMetadata (const QgsLayerMetadata &metadata)
	Sets the layer's metadata store. More...
void	setMetadataUrl (const QString &metaUrl)
	Sets the metadata URL of the layer used by QGIS Server in GetCapabilities request. More...
void	setMetadataUrlFormat (const QString &metaUrlFormat)
	Sets the metadata format of the layer used by QGIS Server in GetCapabilities request. More...
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. More...
void	setName (const QString &name)
	Set the display name of the layer. More...
void	setRenderer3D (QgsAbstract3DRenderer *renderer)
	Sets 3D renderer for the layer. More...
void	setShortName (const QString &shortName)
	Sets the short name of the layer used by QGIS Server to identify the layer. More...
virtual void	setSubLayerVisibility (const QString &name, bool visible)
	Set the visibility of the given sublayer name. More...
void	setTitle (const QString &title)
	Sets the title of the layer used by QGIS Server in GetCapabilities request. More...
QString	shortName () const
	Returns the short name of the layer used by QGIS Server to identify the layer. More...
QString	source () const
	Returns the source for the layer. More...
QgsMapLayerStyleManager *	styleManager () const
	Get access to the layer's style manager. More...
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) More...
virtual QStringList	subLayers () const
	Returns the sublayers of this layer. More...
virtual QDateTime	timestamp () const
	Time stamp of data source in the moment when data/metadata were loaded by provider. More...
QString	title () const
	Returns the title of the layer used by QGIS Server in GetCapabilities request. More...
QgsMapLayer::LayerType	type () const
	Returns the type of the layer. More...
QUndoStack *	undoStack ()
	Return pointer to layer's undo stack. More...
QUndoStack *	undoStackStyles ()
	Return pointer to layer's style undo stack. More...
bool	writeLayerXml (QDomElement &layerElement, QDomDocument &document, const QgsReadWriteContext &context) const
	Stores state in Dom node. More...
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=nullptr)
	Adds all features from the specified iterator to the sink. More...
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. More...
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. More...
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. More...

Static Public Member Functions
static void	drawVertexMarker (double x, double y, QPainter &p, QgsVectorLayer::VertexMarkerType type, int vertexSize)
	Draws a vertex symbol at (screen) coordinates x, y. (Useful to assist vertex editing.) More...
Static Public Member Functions inherited from QgsMapLayer
static QString	extensionPropertyType (PropertyType type)
	Returns the extension of a Property. More...
static QString	formatLayerName (const QString &name)
	A convenience function to capitalize and format a layer name. More...

Protected Member Functions
void	setExtent (const QgsRectangle &rect) override
	Set the extent. More...
Protected Member Functions inherited from QgsMapLayer
void	appendError (const QgsErrorMessage &error)
	Add error message. More...
void	clone (QgsMapLayer *layer) const
	Copies attributes like name, short name, ... More...
bool	hasDependencyCycle (const QSet< QgsMapLayerDependency > &layers) const
	Checks whether a new set of dependencies will introduce a cycle. More...
void	readCommonStyle (const QDomElement &layerElement, const QgsReadWriteContext &context)
	Read style data common to all layer types. More...
void	readCustomProperties (const QDomNode &layerNode, const QString &keyStartsWith=QString())
	Read custom properties from project file. More...
void	readStyleManager (const QDomNode &layerNode)
	Read style manager's configuration (if any). To be called by subclasses. More...
void	setError (const QgsError &error)
	Set error message. More...
void	setValid (bool valid)
	Set whether layer is valid or not - should be used in constructor. More...
void	writeCommonStyle (QDomElement &layerElement, QDomDocument &document, const QgsReadWriteContext &context) const
	Write style data common to all layer types. More...
void	writeCustomProperties (QDomNode &layerNode, QDomDocument &doc) const
	Write custom properties to project file. More...
void	writeStyleManager (QDomNode &layerNode, QDomDocument &doc) const
	Write style manager's configuration (if exists). To be called by subclasses. More...

Properties
QString	displayExpression
QgsEditFormConfig	editFormConfig
QString	mapTipTemplate
double	opacity
bool	readOnly
Properties inherited from QgsMapLayer
int	autoRefreshInterval
QgsLayerMetadata	metadata
QString	name

Friends
class	QgsVectorLayerEditBuffer
class	QgsVectorLayerEditPassthrough
class	QgsVectorLayerFeatureSource

Additional Inherited Members
Protected Attributes inherited from QgsMapLayer
QString	mAbstract
	Description of the layer. More...
QString	mAttribution
	Attribution of the layer. More...
QString	mAttributionUrl
QString	mDataSource
	Data source description string, varies by layer type. More...
QString	mDataUrl
	DataUrl of the layer. More...
QString	mDataUrlFormat
QSet< QgsMapLayerDependency >	mDependencies
	List of layers that may modify this layer on modification. More...
QgsError	mError
	Error. More...
QgsRectangle	mExtent
	Extent of the layer. More...
bool	mIsRefreshOnNofifyEnabled = false
QString	mKeywordList
QString	mLayerName
	Name of the layer - used for display. More...
QString	mLegendUrl
	WMS legend. More...
QString	mLegendUrlFormat
QString	mMetadataUrl
	MetadataUrl of the layer. More...
QString	mMetadataUrlFormat
QString	mMetadataUrlType
QString	mRefreshOnNofifyMessage
QString	mShortName
QString	mTitle
bool	mValid = false
	Indicates if the layer is valid and can be drawn. More...

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.

Sample usage of the QgsVectorLayer class:

QString uri = "point?crs=epsg:4326&field=id:integer";
QgsVectorLayer *scratchLayer = new 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"

OGR data provider (ogr)

Accesses data using the OGR drivers (http://www.gdal.org/ogr/ogr_formats.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, starting with QGIS 2.16, a URI constructed using the QgsDataSourceUri class with the following parameters :

• 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)
• maxNumFeatures=number
• 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’ query string parameter can be used to filter the WFS feature type. 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.

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 QRegExp 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.

TODO QGIS3: Remove virtual from non-inherited methods (like isModified)

See also

QgsVectorLayerUtils()

Definition at line 353 of file qgsvectorlayer.h.

Member Enumeration Documentation

EditResult

enum QgsVectorLayer::EditResult

Result of an edit operation.

Enumerator
Success	Edit operation was successful.
EmptyGeometry	Edit operation resulted in an empty geometry.
EditFailed	Edit operation failed.
FetchFeatureFailed	Unable to fetch requested feature.
InvalidLayer	Edit failed due to invalid layer.

Definition at line 366 of file qgsvectorlayer.h.

SelectBehavior

enum QgsVectorLayer::SelectBehavior

Selection behavior.

Enumerator
SetSelection	Set selection, removing any existing selection.
AddToSelection	Add selection to current selection.
IntersectSelection	Modify current selection to include only select features which match.
RemoveFromSelection	Remove from current selection.

Definition at line 376 of file qgsvectorlayer.h.

VertexMarkerType

enum QgsVectorLayer::VertexMarkerType

Editing vertex markers.

Enumerator
SemiTransparentCircle
Cross
NoMarker

Definition at line 1621 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 136 of file qgsvectorlayer.cpp.

~QgsVectorLayer()

QgsVectorLayer::~QgsVectorLayer ( )

override

Definition at line 174 of file qgsvectorlayer.cpp.

QgsVectorLayer() [2/2]

QgsVectorLayer::QgsVectorLayer ( const QgsVectorLayer &  rhs )

delete

QgsVectorLayer cannot be copied.

Member Function Documentation

actions() [1/2]

QgsActionManager* QgsVectorLayer::actions ( )

inline

Get 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 581 of file qgsvectorlayer.h.

actions() [2/2]

const QgsActionManager* QgsVectorLayer::actions ( ) const

inline

Get all layer actions defined on this layer.

The pointer which is returned is const.

Definition at line 588 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 2416 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

Since

QGIS 2.9

Definition at line 2986 of file qgsvectorlayer.cpp.

addFeature()

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

overridevirtual

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 925 of file qgsvectorlayer.cpp.

addFeatures()

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

overridevirtual

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 2759 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 2970 of file qgsvectorlayer.cpp.

addPart() [1/3]

QgsGeometry::OperationResult QgsVectorLayer::addPart

(

const QList< QgsPointXY > &

ring

)

Adds a new part polygon to a multipart feature.

Returns

QgsGeometry::OperationResult

• 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().

Definition at line 1158 of file qgsvectorlayer.cpp.

addPart() [2/3]

QgsGeometry::OperationResult QgsVectorLayer::addPart

(

const QgsPointSequence &

ring

)

Adds a new part polygon to a multipart feature.

Returns

QgsGeometry::OperationResult

• 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 1184 of file qgsvectorlayer.cpp.

addPart() [3/3]

QgsGeometry::OperationResult 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 1210 of file qgsvectorlayer.cpp.

addRing() [1/2]

QgsGeometry::OperationResult 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

QgsGeometry::OperationResult

• 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 1097 of file qgsvectorlayer.cpp.

addRing() [2/2]

QgsGeometry::OperationResult 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

QgsGeometry::OperationResult

• 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 1120 of file qgsvectorlayer.cpp.

addTopologicalPoints() [1/2]

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

0 in case of success

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 1267 of file qgsvectorlayer.cpp.

addTopologicalPoints() [2/2]

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

0 in case of success

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().

Definition at line 1276 of file qgsvectorlayer.cpp.

aggregate()

QVariant QgsVectorLayer::aggregate	(	QgsAggregateCalculator::Aggregate	aggregate,
		const QString &	fieldOrExpression,
		const QgsAggregateCalculator::AggregateParameters &	parameters = QgsAggregateCalculator::AggregateParameters(),
		QgsExpressionContext *	context = nullptr,
		bool *	ok = nullptr
	)		const

Calculates an aggregated value from the layer's features.

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

Returns

calculated aggregate value

Since

QGIS 2.16

Definition at line 3586 of file qgsvectorlayer.cpp.

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 2492 of file qgsvectorlayer.cpp.

attributeAliases()

QgsStringMap QgsVectorLayer::attributeAliases

(

)

const

Returns a map of field name to attribute alias.

Definition at line 2508 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 2500 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 1325 of file qgsvectorlayer.h.

attributeTableConfig()

QgsAttributeTableConfig QgsVectorLayer::attributeTableConfig

(

)

const

Get the attribute table configuration object.

This defines the appearance of the attribute table.

Definition at line 3906 of file qgsvectorlayer.cpp.

attributeValueChanged

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

signal

Is 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.

Since

QGIS 3.0

Definition at line 4285 of file qgsvectorlayer.cpp.

auxiliaryLayer() [2/2]

const QgsAuxiliaryLayer * QgsVectorLayer::auxiliaryLayer

(

)

const

Returns the current const auxiliary layer.

Since

QGIS 3.0

Definition at line 4280 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 ( )

signal

Is emitted, before changes are committed to the data provider.

beforeEditingStarted

void QgsVectorLayer::beforeEditingStarted ( )

signal

Is emitted, before editing on this layer is started.

beforeModifiedCheck

void QgsVectorLayer::beforeModifiedCheck ( ) const

signal

Is emitted, when 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

Is 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 2925 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 611 of file qgsvectorlayer.cpp.

capabilitiesString()

QString QgsVectorLayer::capabilitiesString

(

)

const

Capabilities for this layer, comma separated and translated.

Definition at line 289 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 2329 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()

Since

QGIS 3.0

Definition at line 2358 of file qgsvectorlayer.cpp.

changeGeometry()

bool QgsVectorLayer::changeGeometry	(	QgsFeatureId	fid,
		const 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 2308 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 identicals.

Returns

a new layer instance

Since

QGIS 3.0

Implements QgsMapLayer.

Definition at line 197 of file qgsvectorlayer.cpp.

commitChanges()

bool QgsVectorLayer::commitChanges

(

)

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.

See also

startEditing()

commitErrors()

rollBack()

Definition at line 2617 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 2659 of file qgsvectorlayer.cpp.

committedAttributesAdded

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

signal

This signal is emitted, when attributes are added to the provider.

committedAttributesDeleted

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

signal

This signal is emitted, when attributes are deleted from the provider.

committedAttributeValuesChanges

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

signal

This signal is emitted, when attribute value changes are saved to the provider.

committedFeaturesAdded

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

signal

This signal is emitted, when features are added to the provider.

committedFeaturesRemoved

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

signal

This signal is emitted, when features are deleted from the provider.

committedGeometriesChanges

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

signal

This signal is emitted, when geometry changes are saved to the provider.

conditionalStyles()

QgsConditionalLayerStyles * QgsVectorLayer::conditionalStyles

(

)

const

Return 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.

Since

QGIS 2.12

Definition at line 912 of file qgsvectorlayer.cpp.

constraintDescription()

QString QgsVectorLayer::constraintDescription

(

int

index

)

const

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

Since

QGIS 3.0

See also

constraints()

constraintExpression()

setConstraintExpression()

Definition at line 4456 of file qgsvectorlayer.cpp.

constraintExpression()

QString QgsVectorLayer::constraintExpression

(

int

index

)

const

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

Since

QGIS 3.0

See also

fieldConstraints()

constraintDescription()

setConstraintExpression()

Definition at line 4448 of file qgsvectorlayer.cpp.

countSymbolFeatures()

QgsVectorLayerFeatureCounter * QgsVectorLayer::countSymbolFeatures

(

)

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.

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.

Since

This is asynchronous since QGIS 3.0

Definition at line 701 of file qgsvectorlayer.cpp.

createExpressionContext()

QgsExpressionContext QgsVectorLayer::createExpressionContext ( ) const

overridevirtual

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

Since

QGIS 3.0

Implements QgsExpressionContextGenerator.

Definition at line 3925 of file qgsvectorlayer.cpp.

createExpressionContextScope()

QgsExpressionContextScope * QgsVectorLayer::createExpressionContextScope ( ) const

overridevirtual

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

Since

QGIS 3.0

Implements QgsExpressionContextScopeGenerator.

Definition at line 3930 of file qgsvectorlayer.cpp.

createMapRenderer()

QgsMapLayerRenderer * QgsVectorLayer::createMapRenderer ( QgsRenderContext &  rendererContext )

overridevirtual

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

Since

QGIS 2.4

Implements QgsMapLayer.

Definition at line 332 of file qgsvectorlayer.cpp.

dataComment()

QString QgsVectorLayer::dataComment

(

)

const

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

Definition at line 298 of file qgsvectorlayer.cpp.

dataProvider() [1/2]

QgsVectorDataProvider * QgsVectorLayer::dataProvider ( )

overridevirtual

Returns the layer's data provider.

Reimplemented from QgsMapLayer.

Definition at line 556 of file qgsvectorlayer.cpp.

dataProvider() [2/2]

const QgsVectorDataProvider * QgsVectorLayer::dataProvider ( ) const

overridevirtual

Returns the layer's data provider in a const-correct manner.

Note

not available in Python bindings

Reimplemented from QgsMapLayer.

Definition at line 561 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

Since

QGIS 3.0

See also

setDefaultValueDefinition()

Definition at line 3136 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

Since

QGIS 3.0

See also

defaultValue()

setDefaultValueDefinition()

Definition at line 3198 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 2519 of file qgsvectorlayer.cpp.

deleteAttributes()

bool QgsVectorLayer::deleteAttributes

(

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 2536 of file qgsvectorlayer.cpp.

deleteFeature()

bool QgsVectorLayer::deleteFeature

(

QgsFeatureId

fid

)

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

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 2556 of file qgsvectorlayer.cpp.

deleteFeatures()

bool QgsVectorLayer::deleteFeatures

(

const QgsFeatureIds &

fids

)

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

Parameters

fids	The feature ids to delete

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 2574 of file qgsvectorlayer.cpp.

deleteSelectedFeatures()

bool QgsVectorLayer::deleteSelectedFeatures

(

int *

deletedCount = nullptr

)

Deletes the selected features.

Returns

true in case of success and false otherwise

Definition at line 1065 of file qgsvectorlayer.cpp.

deleteStyleFromDatabase()

bool QgsVectorLayer::deleteStyleFromDatabase ( const QString &  styleId, QString &  msgError  )

virtual

Delete a style from the database.

Parameters

styleId	the provider's layer_styles table id of the style to delete
msgError	reference to string that will be updated with any error messages

Returns

true in case of success

Since

QGIS 3.0

Definition at line 4166 of file qgsvectorlayer.cpp.

deleteVertex()

QgsVectorLayer::EditResult 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

Since

QGIS 2.14

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 1051 of file qgsvectorlayer.cpp.

dependencies()

QSet< QgsMapLayerDependency > QgsVectorLayer::dependencies ( ) const

overridevirtual

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

Since

QGIS 3.0

Reimplemented from QgsMapLayer.

Definition at line 4317 of file qgsvectorlayer.cpp.

deselect [1/2]

void QgsVectorLayer::deselect ( const QgsFeatureId  featureId )

slot

Deselect feature by its ID.

Parameters

featureId

The id of the feature to deselect

See also

deselect(QgsFeatureIds)

Definition at line 368 of file qgsvectorlayer.cpp.

deselect [2/2]

void QgsVectorLayer::deselect ( const QgsFeatureIds &  featureIds )

slot

Deselect features by their ID.

Parameters

featureIds

The ids of the features to deselect

See also

deselect(QgsFeatureId)

Definition at line 375 of file qgsvectorlayer.cpp.

destroyEditCommand()

void QgsVectorLayer::destroyEditCommand

(

)

Destroy active command and reverts all changes in it.

Definition at line 2957 of file qgsvectorlayer.cpp.

diagramLayerSettings()

const QgsDiagramLayerSettings* QgsVectorLayer::diagramLayerSettings ( ) const

inline

Definition at line 726 of file qgsvectorlayer.h.

diagramRenderer()

const QgsDiagramRenderer* QgsVectorLayer::diagramRenderer ( ) const

inline

Definition at line 723 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

Since

QGIS 2.9

Definition at line 680 of file qgsvectorlayer.cpp.

displayExpression()

QString QgsVectorLayer::displayExpression

(

)

const

Get 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

displayExpressionChanged

void QgsVectorLayer::displayExpressionChanged ( )

signal

Emitted when the display expression changes.

Since

QGIS 3.0

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 2789 of file qgsvectorlayer.cpp.

drawVertexMarker()

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

static

Draws a vertex symbol at (screen) coordinates x, y. (Useful to assist vertex editing.)

Definition at line 338 of file qgsvectorlayer.cpp.

editBuffer() [1/2]

QgsVectorLayerEditBuffer* QgsVectorLayer::editBuffer ( )

inline

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

Definition at line 1600 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 1606 of file qgsvectorlayer.h.

editCommandDestroyed

void QgsVectorLayer::editCommandDestroyed ( )

signal

Signal emitted, whan 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

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

This is a writable configuration that can directly be changed in place.

Returns

The configuration of this layers' form

Since

QGIS 2.14

editFormConfigChanged

void QgsVectorLayer::editFormConfigChanged ( )

signal

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

Since

QGIS 3.0

editingStarted

void QgsVectorLayer::editingStarted ( )

signal

Is emitted, when editing on this layer has started.

editingStopped

void QgsVectorLayer::editingStopped ( )

signal

Is emitted, when edited changes successfully have been written to the data provider.

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.

Since

QGIS 3.0

Definition at line 4492 of file qgsvectorlayer.cpp.

endEditCommand()

void QgsVectorLayer::endEditCommand

(

)

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

Definition at line 2941 of file qgsvectorlayer.cpp.

excludeAttributesWfs()

QSet<QString> QgsVectorLayer::excludeAttributesWfs ( ) const

inline

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

Definition at line 1499 of file qgsvectorlayer.h.

excludeAttributesWms()

QSet<QString> QgsVectorLayer::excludeAttributesWms ( ) const

inline

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

Definition at line 1489 of file qgsvectorlayer.h.

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

Since

QGIS 2.9

Definition at line 3005 of file qgsvectorlayer.cpp.

extent()

QgsRectangle QgsVectorLayer::extent ( ) const

overridevirtual

Returns the extent of the layer.

Reimplemented from QgsMapLayer.

Definition at line 768 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 3631 of file qgsvectorlayer.cpp.

featureBlendModeChanged

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

signal

Signal emitted when setFeatureBlendMode() is called.

featureCount() [1/2]

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 693 of file qgsvectorlayer.cpp.

featureCount() [2/2]

long QgsVectorLayer::featureCount ( ) const

overridevirtual

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.

Implements QgsFeatureSource.

Definition at line 2611 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

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.

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.

Since

QGIS 3.0

See also

setFieldConstraint()

Definition at line 4377 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

Since

QGIS 3.0

Definition at line 4393 of file qgsvectorlayer.cpp.

fields()

QgsFields QgsVectorLayer::fields ( ) const

inlineoverridevirtual

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 1320 of file qgsvectorlayer.h.

geometryChanged

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

signal

Is 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

geometryType()

QgsWkbTypes::GeometryType QgsVectorLayer::geometryType

(

)

const

Returns point, line or polygon.

Definition at line 583 of file qgsvectorlayer.cpp.

getFeature()

QgsFeature QgsVectorLayer::getFeature ( QgsFeatureId  fid ) const

inline

Query the layer for the feature with the given id.

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

Definition at line 981 of file qgsvectorlayer.h.

getFeatures() [1/4]

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

overridevirtual

Query 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 917 of file qgsvectorlayer.cpp.

getFeatures() [2/4]

QgsFeatureIterator QgsVectorLayer::getFeatures ( const QString &  expression )

inline

Query the layer for features matching a given expression.

Definition at line 972 of file qgsvectorlayer.h.

getFeatures() [3/4]

QgsFeatureIterator QgsVectorLayer::getFeatures ( const QgsFeatureIds &  fids )

inline

Query the layer for the features with the given ids.

Definition at line 991 of file qgsvectorlayer.h.

getFeatures() [4/4]

QgsFeatureIterator QgsVectorLayer::getFeatures ( const QgsRectangle &  rectangle )

inline

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

Definition at line 999 of file qgsvectorlayer.h.

getSelectedFeatures()

QgsFeatureIterator QgsVectorLayer::getSelectedFeatures

(

QgsFeatureRequest

request = QgsFeatureRequest()

)

const

Get 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

See also

selectedFeatureIds()

selectedFeatures()

Definition at line 2743 of file qgsvectorlayer.cpp.

getStyleFromDatabase()

QString QgsVectorLayer::getStyleFromDatabase ( const QString &  styleId, QString &  msgError  )

virtual

Will return the named style corresponding to style id provided.

Definition at line 4147 of file qgsvectorlayer.cpp.

htmlMetadata()

QString QgsVectorLayer::htmlMetadata ( ) const

overridevirtual

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

Since

QGIS 3.0

Reimplemented from QgsMapLayer.

Definition at line 3942 of file qgsvectorlayer.cpp.

insertVertex() [1/2]

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

Insert 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 999 of file qgsvectorlayer.cpp.

insertVertex() [2/2]

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

Insert 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 1012 of file qgsvectorlayer.cpp.

invertSelection()

void QgsVectorLayer::invertSelection

(

)

Select not selected features and deselect selected ones.

Definition at line 507 of file qgsvectorlayer.cpp.

invertSelectionInRectangle()

void QgsVectorLayer::invertSelectionInRectangle

(

QgsRectangle &

rect

)

Invert 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 519 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.

Since

QGIS 3.0

Definition at line 2889 of file qgsvectorlayer.cpp.

isEditable()

bool QgsVectorLayer::isEditable ( ) const

overridevirtual

Returns true if the provider is in editing mode.

Reimplemented from QgsMapLayer.

Definition at line 2855 of file qgsvectorlayer.cpp.

isEditCommandActive()

bool QgsVectorLayer::isEditCommandActive ( ) const

inline

Test if an edit command is active.

Since

QGIS 3.0

Definition at line 1954 of file qgsvectorlayer.h.

isModified()

bool QgsVectorLayer::isModified ( ) const

virtual

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

Definition at line 2882 of file qgsvectorlayer.cpp.

isSpatial()

bool QgsVectorLayer::isSpatial ( ) const

overridevirtual

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

Reimplemented from QgsMapLayer.

Definition at line 2860 of file qgsvectorlayer.cpp.

joinBuffer()

QgsVectorLayerJoinBuffer* QgsVectorLayer::joinBuffer ( )

inline

Accessor to the join buffer object.

Since

QGIS 2.14.7

Definition at line 510 of file qgsvectorlayer.h.

labeling() [1/2]

const QgsAbstractVectorLayerLabeling* QgsVectorLayer::labeling ( ) const

inline

Access to const labeling configuration.

May be null if labeling is not used.

Note

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

Since

QGIS 3.0

See also

labelsEnabled()

Definition at line 1269 of file qgsvectorlayer.h.

labeling() [2/2]

QgsAbstractVectorLayerLabeling* QgsVectorLayer::labeling ( )

inline

Access to labeling configuration.

May be null if labeling is not used.

Note

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

Since

QGIS 3.0

See also

labelsEnabled()

Definition at line 1277 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

Since

QGIS 2.9

See also

setLabelsEnabled()

Definition at line 670 of file qgsvectorlayer.cpp.

layerModified

void QgsVectorLayer::layerModified ( )

signal

This signal is emitted when modifications has been done on layer.

listStylesInDatabase()

int QgsVectorLayer::listStylesInDatabase ( QStringList &  ids, QStringList &  names, QStringList &  descriptions, QString &  msgError  )

virtual

Lists all the style in db split into related to the layer and not related to.

Parameters

ids	the list in which will be stored the style db ids
names	the list in which will be stored the style names
descriptions	the list in which will be stored the style descriptions
msgError

Returns

the number of styles related to current layer

Definition at line 4128 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

Since

QGIS 3.0

Definition at line 4229 of file qgsvectorlayer.cpp.

loadNamedStyle() [1/2]

QString QgsVectorLayer::loadNamedStyle ( const QString &  theURI, bool &  resultFlag, bool  loadFromLocalDb  )

virtual

Load a named style from file/local db/datasource db.

Parameters

theURI	the URI of the style or the URI of the layer
resultFlag	will be set to true if a named style is correctly loaded
loadFromLocalDb	if true forces to load from local db instead of datasource one

Definition at line 4290 of file qgsvectorlayer.cpp.

loadNamedStyle() [2/2]

QString QgsVectorLayer::loadNamedStyle ( const QString &  theURI, bool &  resultFlag  )

overridevirtual

Calls loadNamedStyle( theURI, resultFlag, false ); Retained for backward compatibility.

Reimplemented from QgsMapLayer.

Definition at line 4224 of file qgsvectorlayer.cpp.

mapTipTemplate()

QString QgsVectorLayer::mapTipTemplate

(

)

const

The mapTip is a pretty, html representation for feature information.

It may also contain embedded expressions.

Since

QGIS 3.0

mapTipTemplateChanged

void QgsVectorLayer::mapTipTemplateChanged ( )

signal

Emitted when the map tip changes.

Since

QGIS 3.0

maximumValue()

QVariant QgsVectorLayer::maximumValue ( int  index ) const

overridevirtual

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

Note that 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).

See also

minimumValue()

uniqueValues()

Reimplemented from QgsFeatureSource.

Definition at line 3501 of file qgsvectorlayer.cpp.

minimumValue()

QVariant QgsVectorLayer::minimumValue ( int  index ) const

overridevirtual

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

Note that 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).

See also

maximumValue()

uniqueValues()

Reimplemented from QgsFeatureSource.

Definition at line 3413 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

select(QgsFeatureIds)

select(QgsFeatureId)

deselect(QgsFeatureIds)

deselect(QgsFeatureId)

selectByExpression()

Definition at line 493 of file qgsvectorlayer.cpp.

moveVertex() [1/2]

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 1025 of file qgsvectorlayer.cpp.

moveVertex() [2/2]

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 1038 of file qgsvectorlayer.cpp.

opacity()

double QgsVectorLayer::opacity

(

)

const

Returns the opacity for the vector layer, where opacity is a value between 0 (totally transparent) and 1.0 (fully opaque).

See also

setOpacity()

opacityChanged()

Since

QGIS 3.0

opacityChanged

void QgsVectorLayer::opacityChanged ( double  opacity )

signal

Emitted when the layer's opacity is changed, where opacity is a value between 0 (transparent) and 1 (opaque).

Since

QGIS 3.0

See also

setOpacity()

opacity()

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 2596 of file qgsvectorlayer.cpp.

providerType()

QString QgsVectorLayer::providerType

(

)

const

Return the provider type for this layer.

Definition at line 308 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.

Since

QGIS 3.0

Definition at line 4531 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.

Since

QGIS 3.0

readSld()

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

overridevirtual

Reimplemented from QgsMapLayer.

Definition at line 2247 of file qgsvectorlayer.cpp.

readStyle()

bool QgsVectorLayer::readStyle ( const QDomNode &  node, QString &  errorMessage, const QgsReadWriteContext &  context  )

overridevirtual

Read the style for the current layer from the Dom node supplied.

Parameters

node	node that will contain the style definition for this layer.
errorMessage	reference to string that will be updated with any error messages
context	reading context (used for transform from relative to absolute paths)

Returns

true in case of success.

Reimplemented from QgsMapLayer.

Definition at line 1879 of file qgsvectorlayer.cpp.

readSymbology()

bool QgsVectorLayer::readSymbology ( const QDomNode &  layerNode, QString &  errorMessage, const QgsReadWriteContext &  context  )

overridevirtual

Read the symbology for the current layer from the Dom node supplied.

Parameters

layerNode	node that will contain the symbology definition for this layer.
errorMessage	reference to string that will be updated with any error messages
context	reading context (used for transform from relative to absolute paths)

Returns

true in case of success.

Implements QgsMapLayer.

Definition at line 1689 of file qgsvectorlayer.cpp.

readXml()

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

overridevirtual

Reads vector layer specific state from project file Dom node.

Note

Called by QgsMapLayer::readXml().

Reimplemented from QgsMapLayer.

Definition at line 1356 of file qgsvectorlayer.cpp.

referencingRelations()

QList< QgsRelation > QgsVectorLayer::referencingRelations

(

int

idx

)

const

Get 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 4123 of file qgsvectorlayer.cpp.

reload()

void QgsVectorLayer::reload ( )

overridevirtual

Synchronises with changes in the datasource.

Reimplemented from QgsMapLayer.

Definition at line 323 of file qgsvectorlayer.cpp.

removeExpressionField()

void QgsVectorLayer::removeExpressionField

(

int

index

)

Remove an expression field.

Parameters

index

The index of the field

Since

QGIS 2.6

Definition at line 2996 of file qgsvectorlayer.cpp.

removeFieldAlias()

void QgsVectorLayer::removeFieldAlias

(

int

index

)

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

Since

QGIS 3.0

Definition at line 2424 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.

Since

QGIS 3.0

See also

fieldConstraints()

setFieldConstraint()

Definition at line 4431 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 2976 of file qgsvectorlayer.cpp.

removeSelection

void QgsVectorLayer::removeSelection ( )

slot

Clear selection.

See also

selectByIds()

Definition at line 548 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

Since

QGIS 2.16

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 2440 of file qgsvectorlayer.cpp.

renderer() [1/2]

QgsFeatureRenderer* QgsVectorLayer::renderer ( )

inline

Return renderer.

Definition at line 729 of file qgsvectorlayer.h.

renderer() [2/2]

const QgsFeatureRenderer* QgsVectorLayer::renderer ( ) const

inline

Return const renderer.

Note

not available in Python bindings

Definition at line 735 of file qgsvectorlayer.h.

resolveReferences()

void QgsVectorLayer::resolveReferences ( QgsProject *  project )

overridevirtual

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

Since

QGIS 3.0

Reimplemented from QgsMapLayer.

Definition at line 1682 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 2664 of file qgsvectorlayer.cpp.

saveStyleToDatabase()

void QgsVectorLayer::saveStyleToDatabase ( const QString &  name, const QString &  description, bool  useAsDefault, const QString &  uiFileContent, QString &  msgError  )

virtual

Save named and sld style of the layer to the style table in the db.

Parameters

name
description
useAsDefault
uiFileContent
msgError

Definition at line 4184 of file qgsvectorlayer.cpp.

select [1/2]

void QgsVectorLayer::select ( QgsFeatureId  featureId )

slot

Select feature by its ID.

Parameters

featureId

The id of the feature to select

See also

select(QgsFeatureIds)

Definition at line 354 of file qgsvectorlayer.cpp.

select [2/2]

void QgsVectorLayer::select ( const QgsFeatureIds &  featureIds )

slot

Select features by their ID.

Parameters

featureIds

The ids of the features to select

See also

select(QgsFeatureId)

Definition at line 361 of file qgsvectorlayer.cpp.

selectAll()

void QgsVectorLayer::selectAll

(

)

Select all the features.

Definition at line 514 of file qgsvectorlayer.cpp.

selectByExpression()

void QgsVectorLayer::selectByExpression	(	const QString &	expression,
		QgsVectorLayer::SelectBehavior	behavior = SetSelection
	)

Select 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.

Since

QGIS 2.16

See also

selectByRect()

selectByIds()

Definition at line 404 of file qgsvectorlayer.cpp.

selectByIds()

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

Select 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.

Since

QGIS 2.16

See also

selectByRect()

selectByExpression()

Definition at line 464 of file qgsvectorlayer.cpp.

selectByRect()

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

Select 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 382 of file qgsvectorlayer.cpp.

selectedFeatureCount()

int QgsVectorLayer::selectedFeatureCount

(

)

const

The number of features that are selected in this layer.

Returns

See description

Definition at line 2705 of file qgsvectorlayer.cpp.

selectedFeatureIds()

const QgsFeatureIds & QgsVectorLayer::selectedFeatureIds

(

)

const

Return reference to identifiers of selected features.

Returns

A list of QgsFeatureId

See also

selectedFeatures()

Definition at line 2710 of file qgsvectorlayer.cpp.

selectedFeatures()

QgsFeatureList QgsVectorLayer::selectedFeatures

(

)

const

Get a copy of the user-selected features.

Returns

A list of QgsFeature

See also

selectedFeatureIds()

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

Definition at line 2715 of file qgsvectorlayer.cpp.

selectionChanged

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

signal

This signal is 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

setAttributeTableConfig()

void QgsVectorLayer::setAttributeTableConfig

(

const QgsAttributeTableConfig &

attributeTableConfig

)

Set the attribute table configuration object.

This defines the appearance of the attribute table.

Definition at line 3916 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.

Since

QGIS 3.0

Definition at line 4258 of file qgsvectorlayer.cpp.

setConstraintExpression()

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

Set 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.

Since

QGIS 3.0

See also

constraintExpression()

constraintDescription()

constraints()

Definition at line 4464 of file qgsvectorlayer.cpp.

setCoordinateSystem()

void QgsVectorLayer::setCoordinateSystem

(

)

Setup the coordinate system transformation for the layer.

Definition at line 2773 of file qgsvectorlayer.cpp.

setDataSource()

void QgsVectorLayer::setDataSource	(	const QString &	dataSource,
		const QString &	baseName,
		const QString &	provider,
		bool	loadDefaultStyleFlag = false
	)

Update the data source of the layer.

The layer's renderer and legend will be preserved only if the geometry type of the new data source matches the current geometry type of the layer.

Parameters

dataSource	new layer data source
baseName	base name of the layer
provider	provider string
loadDefaultStyleFlag	set to true to reset the layer's style to the default for the data source

Since

QGIS 2.10

Definition at line 1451 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.

Since

QGIS 3.0

See also

defaultValue()

defaultValueDefinition()

Definition at line 3182 of file qgsvectorlayer.cpp.

setDependencies()

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

overridevirtual

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

Since

QGIS 3.0

Reimplemented from QgsMapLayer.

Definition at line 4324 of file qgsvectorlayer.cpp.

setDiagramLayerSettings()

void QgsVectorLayer::setDiagramLayerSettings

(

const QgsDiagramLayerSettings &

s

)

Definition at line 3935 of file qgsvectorlayer.cpp.

setDiagramRenderer()

void QgsVectorLayer::setDiagramRenderer

(

QgsDiagramRenderer *

r

)

Sets diagram rendering object (takes ownership)

Definition at line 575 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 2800 of file qgsvectorlayer.cpp.

setEditFormConfig()

void QgsVectorLayer::setEditFormConfig

(

const QgsEditFormConfig &

editFormConfig

)

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

This is a writable configuration that can directly be changed in place.

Returns

The configuration of this layers' form

Since

QGIS 3.0

Definition at line 3882 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.

Since

QGIS 3.0

Definition at line 4480 of file qgsvectorlayer.cpp.

setExcludeAttributesWfs()

void QgsVectorLayer::setExcludeAttributesWfs ( const QSet< QString > &  att )

inline

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

Definition at line 1504 of file qgsvectorlayer.h.

setExcludeAttributesWms()

void QgsVectorLayer::setExcludeAttributesWms ( const QSet< QString > &  att )

inline

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

Definition at line 1494 of file qgsvectorlayer.h.

setExtent()

void QgsVectorLayer::setExtent ( const QgsRectangle &  rect )

overrideprotectedvirtual

Set the extent.

Reimplemented from QgsMapLayer.

Definition at line 743 of file qgsvectorlayer.cpp.

setFeatureBlendMode()

void QgsVectorLayer::setFeatureBlendMode

(

QPainter::CompositionMode

blendMode

)

Set the blending mode used for rendering each feature.

Definition at line 3624 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.

Since

QGIS 3.0

Definition at line 2479 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.

Since

QGIS 3.0

See also

fieldConstraints()

removeFieldConstraint()

Definition at line 4414 of file qgsvectorlayer.cpp.

setLabeling()

void QgsVectorLayer::setLabeling

(

QgsAbstractVectorLayerLabeling *

labeling

)

Set labeling configuration.

Takes ownership of the object.

Since

QGIS 3.0

Definition at line 1285 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 675 of file qgsvectorlayer.cpp.

setMapTipTemplate()

void QgsVectorLayer::setMapTipTemplate

(

const QString &

mapTipTemplate

)

The mapTip is a pretty, html representation for feature information.

It may also contain embedded expressions.

Since

QGIS 3.0

Definition at line 3897 of file qgsvectorlayer.cpp.

setOpacity()

void QgsVectorLayer::setOpacity

(

double

opacity

)

Sets the opacity for the vector layer, where opacity is a value between 0 (totally transparent) and 1.0 (fully opaque).

See also

opacity()

opacityChanged()

Since

QGIS 3.0

Definition at line 3636 of file qgsvectorlayer.cpp.

setProviderEncoding()

void QgsVectorLayer::setProviderEncoding

(

const QString &

encoding

)

Sets the textencoding of the data provider.

Definition at line 566 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.

Since

QGIS 3.0

Definition at line 4526 of file qgsvectorlayer.cpp.

setReadOnly()

bool QgsVectorLayer::setReadOnly

(

bool

readonly = true

)

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

Returns

false if the layer is in editing yet

Definition at line 2871 of file qgsvectorlayer.cpp.

setRenderer()

void QgsVectorLayer::setRenderer

(

QgsFeatureRenderer *

r

)

Set renderer which will be invoked to represent this layer.

Ownership is transferred.

Definition at line 2908 of file qgsvectorlayer.cpp.

setSimplifyMethod()

void QgsVectorLayer::setSimplifyMethod ( const QgsVectorSimplifyMethod &  simplifyMethod )

inline

Set the simplification settings for fast rendering of features.

Since

QGIS 2.2

Definition at line 1853 of file qgsvectorlayer.h.

setSubsetString()

bool QgsVectorLayer::setSubsetString ( const QString &  subset )

virtual

Set 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 879 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!

Since

QGIS 2.2

Definition at line 900 of file qgsvectorlayer.cpp.

simplifyMethod()

const QgsVectorSimplifyMethod& QgsVectorLayer::simplifyMethod ( ) const

inline

Returns the simplification settings for fast rendering of features.

Since

QGIS 2.2

Definition at line 1859 of file qgsvectorlayer.h.

sourceCrs()

QgsCoordinateReferenceSystem QgsVectorLayer::sourceCrs ( ) const

overridevirtual

Returns the coordinate reference system for features in the source.

Implements QgsFeatureSource.

Definition at line 313 of file qgsvectorlayer.cpp.

sourceExtent()

QgsRectangle QgsVectorLayer::sourceExtent ( ) const

overridevirtual

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 864 of file qgsvectorlayer.cpp.

sourceName()

QString QgsVectorLayer::sourceName ( ) const

overridevirtual

Returns a friendly display name for the source.

The returned value can be an empty string.

Implements QgsFeatureSource.

Definition at line 318 of file qgsvectorlayer.cpp.

splitFeatures()

QgsGeometry::OperationResult 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

QgsGeometry::OperationResult

• 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 1258 of file qgsvectorlayer.cpp.

splitParts()

QgsGeometry::OperationResult 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

QgsGeometry::OperationResult

• 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 1249 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 1294 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 279 of file qgsvectorlayer.cpp.

subsetString()

QString QgsVectorLayer::subsetString ( ) const

virtual

Get 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 869 of file qgsvectorlayer.cpp.

symbolFeatureCountMapChanged

void QgsVectorLayer::symbolFeatureCountMapChanged ( )

signal

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

Since

QGIS 3.0

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 1236 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 3312 of file qgsvectorlayer.cpp.

uniqueValues()

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

overridevirtual

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 3206 of file qgsvectorlayer.cpp.

updatedFields

void QgsVectorLayer::updatedFields ( )

signal

Is 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

Since

QGIS 2.9

Definition at line 3014 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 736 of file qgsvectorlayer.cpp.

updateFeature()

bool QgsVectorLayer::updateFeature	(	const 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 943 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 3020 of file qgsvectorlayer.cpp.

vectorJoins()

const QList< QgsVectorLayerJoinInfo > QgsVectorLayer::vectorJoins

(

)

const

Definition at line 2981 of file qgsvectorlayer.cpp.

wkbType()

QgsWkbTypes::Type QgsVectorLayer::wkbType ( ) const

overridevirtual

Returns the WKBType or WKBUnknown in case of error.

Implements QgsFeatureSource.

Definition at line 606 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 QgsStringMap &	props = QgsStringMap()
	)		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 2270 of file qgsvectorlayer.cpp.

writeStyle()

bool QgsVectorLayer::writeStyle ( QDomNode &  node, QDomDocument &  doc, QString &  errorMessage, const QgsReadWriteContext &  context  ) const

overridevirtual

Write just the style information for the layer into the document.

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
context	writing context (used for transform from absolute to relative paths)

Returns

true in case of success.

Reimplemented from QgsMapLayer.

Definition at line 2188 of file qgsvectorlayer.cpp.

writeSymbology()

bool QgsVectorLayer::writeSymbology ( QDomNode &  node, QDomDocument &  doc, QString &  errorMessage, const QgsReadWriteContext &  context  ) const

overridevirtual

Write the symbology for the layer into the docment provided.

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
context	writing context (used for transform from absolute to relative paths)

Returns

true in case of success.

Implements QgsMapLayer.

Definition at line 2046 of file qgsvectorlayer.cpp.

writeXml()

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

overridevirtual

Write vector layer specific state to project file Dom node.

Note

Called by QgsMapLayer::writeXml().

Reimplemented from QgsMapLayer.

Definition at line 1606 of file qgsvectorlayer.cpp.

Friends And Related Function Documentation

QgsVectorLayerEditBuffer

friend class QgsVectorLayerEditBuffer

friend

Definition at line 2389 of file qgsvectorlayer.h.

QgsVectorLayerEditPassthrough

friend class QgsVectorLayerEditPassthrough

friend

Definition at line 2390 of file qgsvectorlayer.h.

QgsVectorLayerFeatureSource

friend class QgsVectorLayerFeatureSource

friend

Definition at line 2433 of file qgsvectorlayer.h.

Property Documentation

displayExpression

QString QgsVectorLayer::displayExpression

readwrite

Definition at line 357 of file qgsvectorlayer.h.

editFormConfig

QgsEditFormConfig QgsVectorLayer::editFormConfig

readwrite

Definition at line 359 of file qgsvectorlayer.h.

mapTipTemplate

QString QgsVectorLayer::mapTipTemplate

readwrite

Definition at line 358 of file qgsvectorlayer.h.

opacity

double QgsVectorLayer::opacity

readwrite

Definition at line 361 of file qgsvectorlayer.h.

readOnly

bool QgsVectorLayer::readOnly

readwrite

Definition at line 360 of file qgsvectorlayer.h.

---

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

• /tmp/buildd/qgis-3.0.2+14stretch/src/core/qgsvectorlayer.h
• /tmp/buildd/qgis-3.0.2+14stretch/src/core/qgsvectorlayer.cpp