QgsGroupLayer Class Reference

A map layer which consists of a set of child layers, where all component layers are rendered as a single flattened object during map renders. More...

#include <qgsgrouplayer.h>

Inheritance diagram for QgsGroupLayer:

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

Public Member Functions
	QgsGroupLayer (const QString &name, const QgsGroupLayer::LayerOptions &options)
	Constructor for a new QgsGroupLayer with the specified layer name.
	~QgsGroupLayer () override
QList< QgsMapLayer * >	childLayers () const
	Returns the child layers contained by the group.
QgsGroupLayer *	clone () const override
	Returns a new instance equivalent to this one except for the id which is still unique.
QgsMapLayerRenderer *	createMapRenderer (QgsRenderContext &rendererContext) override
	Returns new instance of QgsMapLayerRenderer that will be used for rendering of given context.
const QgsDataProvider *	dataProvider () const override
	Returns the layer's data provider in a const-correct manner, it may be nullptr.
QgsDataProvider *	dataProvider () override
	Returns the layer's data provider, it may be nullptr.
QgsRectangle	extent () const override
	Returns the extent of the layer.
QString	htmlMetadata () const override
	Obtain a formatted HTML string containing assorted metadata for this layer.
QgsPaintEffect *	paintEffect () const
	Returns the current paint effect for the group layer.
void	prepareLayersForRemovalFromGroup ()
	Prepares all child layers in the group prior to removal from the group.
bool	readSymbology (const QDomNode &node, QString &errorMessage, QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories) override
	Read the symbology for the current layer from the DOM node supplied.
bool	readXml (const QDomNode &layerNode, QgsReadWriteContext &context) override
	Called by readLayerXML(), used by children to read state specific to them from project files.
void	resolveReferences (QgsProject *project) override
	Resolve references to other layers (kept as layer IDs after reading XML) into layer objects.
void	setChildLayers (const QList< QgsMapLayer * > &layers)
	Sets the child layers contained by the group.
void	setPaintEffect (QgsPaintEffect *effect)
	Sets the current paint effect for the renderer.
void	setTransformContext (const QgsCoordinateTransformContext &context) override
	Sets the coordinate transform context to transformContext.
bool	writeSymbology (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &, StyleCategories categories=AllStyleCategories) const override
	Write the style for the layer into the document provided.
bool	writeXml (QDomNode &layer_node, QDomDocument &doc, const QgsReadWriteContext &context) const override
	Called by writeLayerXML(), used by children to write state specific to them to project files.
Public Member Functions inherited from QgsMapLayer
	QgsMapLayer (Qgis::LayerType type=Qgis::LayerType::Vector, const QString &name=QString(), const QString &source=QString())
	Constructor for QgsMapLayer.
	QgsMapLayer (QgsMapLayer const &)=delete
	QgsMapLayer cannot be copied.
	~QgsMapLayer () override
QString	abstract () const
	Returns the abstract of the layer used by QGIS Server in GetCapabilities request.
virtual bool	accept (QgsStyleEntityVisitorInterface *visitor) const
	Accepts the specified symbology visitor, causing it to visit all symbols associated with the layer.
QString	attribution () const
	Returns the attribution of the layer used by QGIS Server in GetCapabilities request.
QString	attributionUrl () const
	Returns the attribution URL of the layer used by QGIS Server in GetCapabilities request.
int	autoRefreshInterval () const
	Returns the auto refresh interval (in milliseconds).
Qgis::AutoRefreshMode	autoRefreshMode () const
	Returns the layer's automatical refresh mode.
QPainter::CompositionMode	blendMode () const
	Returns the current blending mode for a layer.
QgsCoordinateReferenceSystem	crs () const
	Returns the layer's spatial reference system.
template<class T >
T	customEnumProperty (const QString &key, const T &defaultValue)
	Returns the property value for a property based on an enum.
template<class T >
T	customFlagProperty (const QString &key, const T &defaultValue)
	Returns the property value for a property based on a flag.
const QgsObjectCustomProperties &	customProperties () const
	Read all custom properties from layer.
Q_INVOKABLE QVariant	customProperty (const QString &value, const QVariant &defaultValue=QVariant()) const
	Read a custom property from layer.
Q_INVOKABLE QStringList	customPropertyKeys () const
	Returns list of all keys within custom properties.
QString	dataUrl () const
	Returns the DataUrl of the layer used by QGIS Server in GetCapabilities request.
QString	dataUrlFormat () const
	Returns the DataUrl format of the layer used by QGIS Server in GetCapabilities request.
virtual bool	deleteStyleFromDatabase (const QString &styleId, QString &msgError)
	Deletes a style from the database.
virtual QSet< QgsMapLayerDependency >	dependencies () const
	Gets the list of dependencies.
virtual QgsMapLayerElevationProperties *	elevationProperties ()
	Returns the layer's elevation properties.
virtual QgsError	error () const
	Gets current status error.
void	exportNamedMetadata (QDomDocument &doc, QString &errorMsg) const
	Export the current metadata of this layer as named metadata in a QDomDocument.
virtual void	exportNamedStyle (QDomDocument &doc, QString &errorMsg, const QgsReadWriteContext &context=QgsReadWriteContext(), QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories) const
	Export the properties of this layer as named style in a QDomDocument.
virtual void	exportSldStyle (QDomDocument &doc, QString &errorMsg) const
	Export the properties of this layer as SLD style in a QDomDocument.
virtual void	exportSldStyleV2 (QDomDocument &doc, QString &errorMsg, const QgsSldExportContext &exportContext) const
	Export the properties of this layer as SLD style in a QDomDocument.
QgsMapLayer::LayerFlags	flags () const
	Returns the flags for this layer.
virtual QString	getStyleFromDatabase (const QString &styleId, QString &msgError)
	Returns the named style corresponding to style id provided.
Q_DECL_DEPRECATED bool	hasAutoRefreshEnabled () const
	Returns true if auto refresh is enabled for the layer.
virtual bool	hasMapTips () const
	Returns true if the layer contains map tips.
bool	hasScaleBasedVisibility () const
	Returns whether scale based visibility is enabled for the layer.
QString	id () const
	Returns the layer's unique ID, which is used to access this layer from QgsProject.
bool	importNamedMetadata (QDomDocument &document, QString &errorMessage)
	Import the metadata of this layer from a QDomDocument.
virtual bool	importNamedStyle (QDomDocument &doc, QString &errorMsg, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories)
	Import the properties of this layer from a QDomDocument.
virtual bool	isEditable () const
	Returns true if the layer can be edited.
bool	isInScaleRange (double scale) const
	Tests whether the layer should be visible at the specified scale.
virtual bool	isModified () const
	Returns true if the layer has been modified since last commit/save.
bool	isRefreshOnNotifyEnabled () const
	Returns true if the refresh on provider nofification is enabled.
virtual bool	isSpatial () const
	Returns true if the layer is considered a spatial layer, ie it has some form of geometry associated with it.
virtual bool	isTemporary () const
	Returns true if the layer is considered a temporary layer.
bool	isValid () const
	Returns the status of the layer.
QString	keywordList () const
	Returns the keyword list of the layer used by QGIS Server in GetCapabilities request.
QgsMapLayerLegend *	legend () const
	Can be nullptr.
QString	legendPlaceholderImage () const
	Returns path to the placeholder image or an empty string if a generated legend is shown.
QString	legendUrl () const
	Returns the URL for the layer's legend.
QString	legendUrlFormat () const
	Returns the format for a URL based layer legend.
virtual int	listStylesInDatabase (QStringList &ids, QStringList &names, QStringList &descriptions, QString &msgError)
	Lists all the style in db split into related to the layer and not related to.
virtual QString	loadDefaultMetadata (bool &resultFlag)
	Retrieve the default metadata for this layer if one exists (either as a .qmd file on disk or as a record in the users metadata table in their personal qgis.db)
virtual QString	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)
virtual QString	loadNamedMetadata (const QString &uri, bool &resultFlag)
	Retrieve a named metadata for this layer if one exists (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db)
bool	loadNamedMetadataFromDatabase (const QString &db, const QString &uri, QString &qmd)
	Retrieve a named metadata for this layer from a sqlite database.
virtual QString	loadNamedStyle (const QString &theURI, bool &resultFlag, bool loadFromLocalDb, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories)
	Loads a named style from file/local db/datasource db.
virtual QString	loadNamedStyle (const QString &uri, bool &resultFlag, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories)
	Retrieve a named style for this layer if one exists (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
virtual bool	loadNamedStyleFromDatabase (const QString &db, const QString &uri, QString &qml)
	Retrieve a named style for this layer from a sqlite database.
virtual QString	loadSldStyle (const QString &uri, bool &resultFlag)
	Attempts to style the layer using the formatting from an SLD type file.
bool	mapTipsEnabled () const
	Returns true if map tips are enabled for this layer.
QString	mapTipTemplate () const
	The mapTip is a pretty, html representation for feature information.
double	maximumScale () const
	Returns the maximum map scale (i.e.
virtual const QgsLayerMetadata &	metadata () const
	Returns a reference to the layer's metadata store.
virtual QString	metadataUri () const
	Retrieve the metadata URI for this layer (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db)
Q_DECL_DEPRECATED QString	metadataUrl () const
	Returns the metadata URL of the layer used by QGIS Server in GetCapabilities request.
Q_DECL_DEPRECATED QString	metadataUrlFormat () const
	Returns the metadata format of the layer used by QGIS Server in GetCapabilities request.
Q_DECL_DEPRECATED QString	metadataUrlType () const
	Returns the metadata type of the layer used by QGIS Server in GetCapabilities request.
double	minimumScale () const
	Returns the minimum map scale (i.e.
QString	name () const
	Returns the display name of the layer.
virtual double	opacity () const
	Returns the opacity for the layer, where opacity is a value between 0 (totally transparent) and 1.0 (fully opaque).
QgsMapLayer &	operator= (QgsMapLayer const &)=delete
	QgsMapLayer cannot be copied.
QString	originalXmlProperties () const
	Returns the XML properties of the original layer as they were when the layer was first read from the project file.
virtual Qgis::MapLayerProperties	properties () const
	Returns the map layer properties of this layer.
QString	providerType () const
	Returns the provider type (provider key) for this layer.
QString	publicSource (bool hidePassword=false) const
	Gets a version of the internal layer definition that has sensitive bits removed (for example, the password).
bool	readLayerXml (const QDomElement &layerElement, QgsReadWriteContext &context, QgsMapLayer::ReadFlags flags=QgsMapLayer::ReadFlags(), QgsDataProvider *preloadedProvider=nullptr)
	Sets state from DOM document.
bool	readOnly () const
	Returns if this layer is read only.
virtual bool	readSld (const QDomNode &node, QString &errorMessage)
virtual bool	readStyle (const QDomNode &node, QString &errorMessage, QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories)
	Read the style for the current layer from the DOM node supplied.
QString	refreshOnNotifyMessage () const
	Returns the message that should be notified by the provider to triggerRepaint.
virtual Q_INVOKABLE void	reload ()
	Synchronises with changes in the datasource.
void	removeCustomProperty (const QString &key)
	Remove a custom property from layer.
QgsAbstract3DRenderer *	renderer3D () const
	Returns 3D renderer associated with the layer.
virtual QString	saveDefaultMetadata (bool &resultFlag)
	Save the current metadata of this layer as the default metadata (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db)
virtual Q_DECL_DEPRECATED QString	saveDefaultStyle (bool &resultFlag)
	Save the properties of this layer as the default style (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
virtual QString	saveDefaultStyle (bool &resultFlag, StyleCategories categories)
	Save the properties of this layer as the default style (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
QString	saveNamedMetadata (const QString &uri, bool &resultFlag)
	Save the current metadata of this layer as a named metadata (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db)
virtual QString	saveNamedStyle (const QString &uri, bool &resultFlag, StyleCategories categories=AllStyleCategories)
	Save the properties of this layer as a named style (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
virtual QString	saveSldStyle (const QString &uri, bool &resultFlag) const
	Saves the properties of this layer to an SLD format file.
virtual QString	saveSldStyleV2 (bool &resultFlag, const QgsSldExportContext &exportContext) const
	Saves the properties of this layer to an SLD format file.
virtual void	saveStyleToDatabase (const QString &name, const QString &description, bool useAsDefault, const QString &uiFileContent, QString &msgError, QgsMapLayer::StyleCategories categories=QgsMapLayer::AllStyleCategories)
	Saves named and sld style of the layer to the style table in the db.
virtual QgsMapLayerSelectionProperties *	selectionProperties ()
	Returns the layer's selection properties.
QgsMapLayerServerProperties *	serverProperties ()
	Returns QGIS Server Properties for the map layer.
const QgsMapLayerServerProperties *	serverProperties () const
	Returns QGIS Server Properties const for the map layer.
void	setAbstract (const QString &abstract)
	Sets the abstract of the layer used by QGIS Server in GetCapabilities request.
void	setAttribution (const QString &attrib)
	Sets the attribution of the layer used by QGIS Server in GetCapabilities request.
void	setAttributionUrl (const QString &attribUrl)
	Sets the attribution URL of the layer used by QGIS Server in GetCapabilities request.
Q_DECL_DEPRECATED void	setAutoRefreshEnabled (bool enabled)
	Sets whether auto refresh is enabled for the layer.
void	setAutoRefreshInterval (int interval)
	Sets the auto refresh interval (in milliseconds) for the layer.
void	setAutoRefreshMode (Qgis::AutoRefreshMode mode)
	Sets the automatic refresh mode for the layer.
void	setBlendMode (QPainter::CompositionMode blendMode)
	Set the blending mode used for rendering a layer.
void	setCrs (const QgsCoordinateReferenceSystem &srs, bool emitSignal=true)
	Sets layer's spatial reference system.
template<class T >
void	setCustomEnumProperty (const QString &key, const T &value)
	Set the value of a property based on an enum.
template<class T >
void	setCustomFlagProperty (const QString &key, const T &value)
	Set the value of a property based on a flag.
void	setCustomProperties (const QgsObjectCustomProperties &properties)
	Set custom properties for layer.
Q_INVOKABLE void	setCustomProperty (const QString &key, const QVariant &value)
	Set a custom property for layer.
void	setDataSource (const QString &dataSource, const QString &baseName, const QString &provider, bool loadDefaultStyleFlag=false)
	Updates the data source of the layer.
void	setDataSource (const QString &dataSource, const QString &baseName, const QString &provider, const QgsDataProvider::ProviderOptions &options, bool loadDefaultStyleFlag=false)
	Updates the data source of the layer.
void	setDataSource (const QString &dataSource, const QString &baseName, const QString &provider, const QgsDataProvider::ProviderOptions &options, QgsDataProvider::ReadFlags flags)
	Updates the data source of the layer.
void	setDataUrl (const QString &dataUrl)
	Sets the DataUrl of the layer used by QGIS Server in GetCapabilities request.
void	setDataUrlFormat (const QString &dataUrlFormat)
	Sets the DataUrl format of the layer used by QGIS Server in GetCapabilities request.
void	setFlags (QgsMapLayer::LayerFlags flags)
	Returns the flags for this layer.
void	setKeywordList (const QString &keywords)
	Sets the keyword list of the layer used by QGIS Server in GetCapabilities request.
virtual void	setLayerOrder (const QStringList &layers)
	Reorders the previously selected sublayers of this layer from bottom to top.
void	setLegend (QgsMapLayerLegend *legend)
	Assign a legend controller to the map layer.
void	setLegendPlaceholderImage (const QString &imgPath)
	Set placeholder image for legend.
void	setLegendUrl (const QString &legendUrl)
	Sets the URL for the layer's legend.
void	setLegendUrlFormat (const QString &legendUrlFormat)
	Sets the format for a URL based layer legend.
void	setMapTipsEnabled (bool enabled)
	Enable or disable map tips for this layer.
void	setMapTipTemplate (const QString &mapTipTemplate)
	The mapTip is a pretty, html representation for feature information.
virtual void	setMetadata (const QgsLayerMetadata &metadata)
	Sets the layer's metadata store.
Q_DECL_DEPRECATED void	setMetadataUrl (const QString &metaUrl)
	Sets the metadata URL of the layer used by QGIS Server in GetCapabilities request.
Q_DECL_DEPRECATED void	setMetadataUrlFormat (const QString &metaUrlFormat)
	Sets the metadata format of the layer used by QGIS Server in GetCapabilities request.
Q_DECL_DEPRECATED void	setMetadataUrlType (const QString &metaUrlType)
	Set the metadata type of the layer used by QGIS Server in GetCapabilities request MetadataUrlType indicates the standard to which the metadata complies.
void	setName (const QString &name)
	Set the display name of the layer.
virtual void	setOpacity (double opacity)
	Sets the opacity for the layer, where opacity is a value between 0 (totally transparent) and 1.0 (fully opaque).
void	setOriginalXmlProperties (const QString &originalXmlProperties)
	Sets the original XML properties for the layer to originalXmlProperties.
void	setRenderer3D (QgsAbstract3DRenderer *renderer)
	Sets 3D renderer for the layer.
void	setShortName (const QString &shortName)
	Sets the short name of the layer used by QGIS Server to identify the layer.
virtual void	setSubLayerVisibility (const QString &name, bool visible)
	Set the visibility of the given sublayer name.
void	setTitle (const QString &title)
	Sets the title of the layer used by QGIS Server in GetCapabilities request.
QString	shortName () const
	Returns the short name of the layer used by QGIS Server to identify the layer.
QString	source () const
	Returns the source for the layer.
QgsMapLayerStyleManager *	styleManager () const
	Gets access to the layer's style manager.
virtual QString	styleURI () const
	Retrieve the style URI for this layer (either as a .qml file on disk or as a record in the users style table in their personal qgis.db)
virtual QStringList	subLayers () const
	Returns the sublayers of this layer.
virtual bool	supportsEditing () const
	Returns whether the layer supports editing or not.
virtual QgsMapLayerTemporalProperties *	temporalProperties ()
	Returns the layer's temporal properties.
virtual QDateTime	timestamp () const
	Time stamp of data source in the moment when data/metadata were loaded by provider.
QString	title () const
	Returns the title of the layer used by QGIS Server in GetCapabilities request.
QgsCoordinateTransformContext	transformContext () const
	Returns the layer data provider coordinate transform context or a default transform context if the layer does not have a valid data provider.
Qgis::LayerType	type () const
	Returns the type of the layer.
QUndoStack *	undoStack ()
	Returns pointer to layer's undo stack.
QUndoStack *	undoStackStyles ()
	Returns pointer to layer's style undo stack.
QgsRectangle	wgs84Extent (bool forceRecalculate=false) const
	Returns the WGS84 extent (EPSG:4326) of the layer according to ReadFlag::FlagTrustLayerMetadata.
bool	writeLayerXml (QDomElement &layerElement, QDomDocument &document, const QgsReadWriteContext &context) const
	Stores state in DOM node.
virtual bool	writeStyle (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories) const
	Write just the symbology information for the layer into the document.

Additional Inherited Members
Public Types inherited from QgsMapLayer
enum	LayerFlag { Identifiable = 1 << 0 , Removable = 1 << 1 , Searchable = 1 << 2 , Private = 1 << 3 }
	Flags for the map layer. More...
enum	PropertyType { Style = 0 , Metadata }
	Maplayer has a style and a metadata property. More...
enum	ReadFlag { FlagDontResolveLayers = 1 << 0 , FlagTrustLayerMetadata = 1 << 1 , FlagReadExtentFromXml = 1 << 2 , FlagForceReadOnly = 1 << 3 }
	Flags which control project read behavior. More...
enum	StyleCategory {   LayerConfiguration = 1 << 0 , Symbology = 1 << 1 , Symbology3D = 1 << 2 , Labeling = 1 << 3 ,   Fields = 1 << 4 , Forms = 1 << 5 , Actions = 1 << 6 , MapTips = 1 << 7 ,   Diagrams = 1 << 8 , AttributeTable = 1 << 9 , Rendering = 1 << 10 , CustomProperties = 1 << 11 ,   GeometryOptions = 1 << 12 , Relations = 1 << 13 , Temporal = 1 << 14 , Legend = 1 << 15 ,   Elevation = 1 << 16 , Notes = 1 << 17 , AllStyleCategories }
	Categories of style to distinguish appropriate sections for import/export. More...
Public Slots inherited from QgsMapLayer
void	emitStyleChanged ()
	Triggers an emission of the styleChanged() signal.
QgsProject *	project () const
	Returns the parent project if this map layer is added to a project.
virtual bool	setDependencies (const QSet< QgsMapLayerDependency > &layers)
	Sets the list of dependencies.
void	setMaximumScale (double scale)
	Sets the maximum map scale (i.e.
void	setMinimumScale (double scale)
	Sets the minimum map scale (i.e.
void	setRefreshOnNofifyMessage (const QString &message)
	Set the notification message that triggers repaint If refresh on notification is enabled, the notification will triggerRepaint only if the notification message is equal to.
void	setRefreshOnNotifyEnabled (bool enabled)
	Set whether provider notification is connected to triggerRepaint.
void	setScaleBasedVisibility (bool enabled)
	Sets whether scale based visibility is enabled for the layer.
void	trigger3DUpdate ()
	Will advise any 3D maps that this layer requires to be updated in the scene.
void	triggerRepaint (bool deferredUpdate=false)
	Will advise the map canvas (and any other interested party) that this layer requires to be repainted.
Signals inherited from QgsMapLayer
void	autoRefreshIntervalChanged (int interval)
	Emitted when the auto refresh interval changes.
void	beforeResolveReferences (QgsProject *project)
	Emitted when all layers are loaded and references can be resolved, just before the references of this layer are resolved.
void	blendModeChanged (QPainter::CompositionMode blendMode)
	Signal emitted when the blend mode is changed, through QgsMapLayer::setBlendMode()
void	configChanged ()
	Emitted whenever the configuration is changed.
void	crsChanged ()
	Emit a signal that layer's CRS has been reset.
void	customPropertyChanged (const QString &key)
	Emitted when a custom property of the layer has been changed or removed.
void	dataChanged ()
	Data of layer changed.
void	dataSourceChanged ()
	Emitted whenever the layer's data source has been changed.
void	dependenciesChanged ()
	Emitted when dependencies are changed.
void	editingStarted ()
	Emitted when editing on this layer has started.
void	editingStopped ()
	Emitted when edited changes have been successfully written to the data provider.
void	flagsChanged ()
	Emitted when layer's flags have been modified.
void	isValidChanged ()
	Emitted when the validity of this layer changed.
void	layerModified ()
	Emitted when modifications has been done on layer.
void	legendChanged ()
	Signal emitted when legend of the layer has changed.
void	mapTipsEnabledChanged ()
	Emitted when map tips are enabled or disabled for the layer.
void	mapTipTemplateChanged ()
	Emitted when the map tip template changes.
void	metadataChanged ()
	Emitted when the layer's metadata is changed.
void	nameChanged ()
	Emitted when the name has been changed.
void	opacityChanged (double opacity)
	Emitted when the layer's opacity is changed, where opacity is a value between 0 (transparent) and 1 (opaque).
void	recalculateExtents () const
	This is used to send a request that any mapcanvas using this layer update its extents.
void	renderer3DChanged ()
	Signal emitted when 3D renderer associated with the layer has changed.
void	rendererChanged ()
	Signal emitted when renderer is changed.
void	repaintRequested (bool deferredUpdate=false)
	By emitting this signal the layer tells that either appearance or content have been changed and any view showing the rendered layer should refresh itself.
void	request3DUpdate ()
	Signal emitted when a layer requires an update in any 3D maps.
void	statusChanged (const QString &status)
	Emit a signal with status (e.g. to be caught by QgisApp and display a msg on status bar)
void	styleChanged ()
	Signal emitted whenever a change affects the layer's style.
void	styleLoaded (QgsMapLayer::StyleCategories categories)
	Emitted when a style has been loaded.
void	willBeDeleted ()
	Emitted in the destructor when the layer is about to be deleted, but it is still in a perfectly valid state: the last chance for other pieces of code for some cleanup if they use the layer.
Static Public Member Functions inherited from QgsMapLayer
static QString	extensionPropertyType (PropertyType type)
	Returns the extension of a Property.
static QString	formatLayerName (const QString &name)
	A convenience function to capitalize and format a layer name.
static QString	generateId (const QString &layerName)
	Generates an unique identifier for this layer, the generate ID is prefixed by layerName.
static QgsDataProvider::ReadFlags	providerReadFlags (const QDomNode &layerNode, QgsMapLayer::ReadFlags layerReadFlags)
	Returns provider read flag deduced from layer read flags layerReadFlags and a dom node layerNode that describes a layer (corresponding to `‘maplayer’' tag in a DOM document project file read by QgsProject).
Protected Member Functions inherited from QgsMapLayer
void	appendError (const QgsErrorMessage &error)
	Add error message.
void	clone (QgsMapLayer *layer) const
	Copies attributes like name, short name, ... into another layer.
QString	crsHtmlMetadata () const
	Returns a HTML fragment containing the layer's CRS metadata, for use in the htmlMetadata() method.
virtual QString	decodedSource (const QString &source, const QString &dataProvider, const QgsReadWriteContext &context) const
	Called by readLayerXML(), used by derived classes to decode provider's specific data source from project files.
virtual QString	encodedSource (const QString &source, const QgsReadWriteContext &context) const
	Called by writeLayerXML(), used by derived classes to encode provider's specific data source to project files.
QString	generalHtmlMetadata () const
	Returns an HTML fragment containing general metadata information, for use in the htmlMetadata() method.
Q_DECL_DEPRECATED bool	hasDependencyCycle (const QSet< QgsMapLayerDependency > &) const
	Checks whether a new set of dependencies will introduce a cycle this method is now deprecated and always return false, because circular dependencies are now correctly managed.
void	invalidateWgs84Extent ()
	Invalidates the WGS84 extent.
void	readCommonStyle (const QDomElement &layerElement, const QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories)
	Read style data common to all layer types.
void	readCustomProperties (const QDomNode &layerNode, const QString &keyStartsWith=QString())
	Read custom properties from project file.
void	readStyleManager (const QDomNode &layerNode)
	Read style manager's configuration (if any). To be called by subclasses.
void	setError (const QgsError &error)
	Sets error message.
virtual void	setExtent (const QgsRectangle &rect)
	Sets the extent.
void	setProviderType (const QString &providerType)
	Sets the providerType (provider key)
void	setValid (bool valid)
	Sets whether layer is valid or not.
void	writeCommonStyle (QDomElement &layerElement, QDomDocument &document, const QgsReadWriteContext &context, StyleCategories categories=AllStyleCategories) const
	Write style data common to all layer types.
void	writeCustomProperties (QDomNode &layerNode, QDomDocument &doc) const
	Write custom properties to project file.
void	writeStyleManager (QDomNode &layerNode, QDomDocument &doc) const
	Write style manager's configuration (if exists). To be called by subclasses.
Protected Attributes inherited from QgsMapLayer
QString	mAbstract
	Description of the layer.
QString	mAttribution
	Attribution of the layer.
QString	mAttributionUrl
int	mBlockStyleChangedSignal = 0
	If non-zero, the styleChanged signal should not be emitted.
QString	mDataSource
	Data source description string, varies by layer type.
QString	mDataUrl
	DataUrl of the layer.
QString	mDataUrlFormat
QSet< QgsMapLayerDependency >	mDependencies
	List of layers that may modify this layer on modification.
QgsError	mError
	Error.
bool	mIsRefreshOnNofifyEnabled = false
QString	mKeywordList
QString	mLayerName
	Name of the layer - used for display.
double	mLayerOpacity = 1.0
	Layer opacity.
QString	mLegendUrl
	WMS legend.
QString	mLegendUrlFormat
std::unique_ptr< QgsDataProvider >	mPreloadedProvider
	Optionally used when loading a project, it is released when the layer is effectively created.
QString	mProviderKey
	Data provider key (name of the data provider)
QgsMapLayer::ReadFlags	mReadFlags = QgsMapLayer::ReadFlags()
	Read flags. It's up to the subclass to respect these when restoring state from XML.
QString	mRefreshOnNofifyMessage
QString	mShortName
bool	mShouldValidateCrs = true
	true if the layer's CRS should be validated and invalid CRSes are not permitted.
QString	mTitle
bool	mValid = false
	Indicates if the layer is valid and can be drawn.
Properties inherited from QgsMapLayer
int	autoRefreshInterval
QgsCoordinateReferenceSystem	crs
bool	isValid
bool	mapTipsEnabled
QString	mapTipTemplate
QgsLayerMetadata	metadata
QString	name
double	opacity
Qgis::LayerType	type

Detailed Description

A map layer which consists of a set of child layers, where all component layers are rendered as a single flattened object during map renders.

Child layers are never owned by QgsGroupLayer. References to layers in a group are stored as weak references only, which wills be automatically cleaned up whenever the linked child layer is deleted.

Since

QGIS 3.24

Definition at line 41 of file qgsgrouplayer.h.

Constructor & Destructor Documentation

QgsGroupLayer()

QgsGroupLayer::QgsGroupLayer	(	const QString &	name,
		const QgsGroupLayer::LayerOptions &	options
	)

Constructor for a new QgsGroupLayer with the specified layer name.

The options argument specifies load-time layer options.

Definition at line 30 of file qgsgrouplayer.cpp.

~QgsGroupLayer()

QgsGroupLayer::~QgsGroupLayer ( )

override

Definition at line 45 of file qgsgrouplayer.cpp.

Member Function Documentation

childLayers()

QList< QgsMapLayer * > QgsGroupLayer::childLayers

(

)

const

Returns the child layers contained by the group.

See also

setChildLayers()

Definition at line 330 of file qgsgrouplayer.cpp.

clone()

QgsGroupLayer * QgsGroupLayer::clone ( ) const

overridevirtual

Returns a new instance equivalent to this one except for the id which is still unique.

Returns

a new layer instance

Since

QGIS 3.0

Implements QgsMapLayer.

Definition at line 51 of file qgsgrouplayer.cpp.

createMapRenderer()

QgsMapLayerRenderer * QgsGroupLayer::createMapRenderer ( QgsRenderContext &  rendererContext )

overridevirtual

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

Since

QGIS 2.4

Implements QgsMapLayer.

Definition at line 63 of file qgsgrouplayer.cpp.

dataProvider() [1/2]

const QgsDataProvider * QgsGroupLayer::dataProvider ( ) const

overridevirtual

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

Note

not available in Python bindings

Reimplemented from QgsMapLayer.

Definition at line 231 of file qgsgrouplayer.cpp.

dataProvider() [2/2]

QgsDataProvider * QgsGroupLayer::dataProvider ( )

overridevirtual

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

Reimplemented from QgsMapLayer.

Definition at line 224 of file qgsgrouplayer.cpp.

extent()

QgsRectangle QgsGroupLayer::extent ( ) const

overridevirtual

Returns the extent of the layer.

Reimplemented from QgsMapLayer.

Definition at line 70 of file qgsgrouplayer.cpp.

htmlMetadata()

QString QgsGroupLayer::htmlMetadata ( ) const

overridevirtual

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

Since

QGIS 3.0

Reimplemented from QgsMapLayer.

Definition at line 238 of file qgsgrouplayer.cpp.

paintEffect()

QgsPaintEffect * QgsGroupLayer::paintEffect

(

)

const

Returns the current paint effect for the group layer.

See also

setPaintEffect()

Definition at line 337 of file qgsgrouplayer.cpp.

prepareLayersForRemovalFromGroup()

void QgsGroupLayer::prepareLayersForRemovalFromGroup

(

)

Prepares all child layers in the group prior to removal from the group.

This method should be called before removing a group layer from a project, to ensure that the existing child layers are in a state which is compatible with non-group layer children.

Since

QGIS 3.30

Definition at line 351 of file qgsgrouplayer.cpp.

readSymbology()

bool QgsGroupLayer::readSymbology ( const QDomNode &  node, QString &  errorMessage, QgsReadWriteContext &  context, StyleCategories  categories = AllStyleCategories  )

overridevirtual

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

Parameters

node	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)
categories	the style categories to be read

Returns

true in case of success.

Implements QgsMapLayer.

Definition at line 183 of file qgsgrouplayer.cpp.

readXml()

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

overridevirtual

Called by readLayerXML(), used by children to read state specific to them from project files.

Reimplemented from QgsMapLayer.

Definition at line 88 of file qgsgrouplayer.cpp.

resolveReferences()

void QgsGroupLayer::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 254 of file qgsgrouplayer.cpp.

setChildLayers()

void QgsGroupLayer::setChildLayers

(

const QList< QgsMapLayer * > &

layers

)

Sets the child layers contained by the group.

This method does not take ownership of the layers, but rather assigns them to the group. Layers should be already added to the parent QgsProject wherever appropriate.

See also

childLayers()

Definition at line 278 of file qgsgrouplayer.cpp.

setPaintEffect()

void QgsGroupLayer::setPaintEffect

(

QgsPaintEffect *

effect

)

Sets the current paint effect for the renderer.

Ownership is transferred to the renderer.

See also

paintEffect()

Definition at line 344 of file qgsgrouplayer.cpp.

setTransformContext()

void QgsGroupLayer::setTransformContext ( const QgsCoordinateTransformContext &  transformContext )

overridevirtual

Sets the coordinate transform context to transformContext.

Since

QGIS 3.8

Implements QgsMapLayer.

Definition at line 77 of file qgsgrouplayer.cpp.

writeSymbology()

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

overridevirtual

Write the style for the layer into the document 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)
categories	the style categories to be written

Note

There is a confusion of terms with the GUI. This method actually writes what is called a style in the application.

Returns

true in case of success.

Implements QgsMapLayer.

Definition at line 151 of file qgsgrouplayer.cpp.

writeXml()

bool QgsGroupLayer::writeXml ( QDomNode &  layer_node, QDomDocument &  document, const QgsReadWriteContext &  context  ) const

overridevirtual

Called by writeLayerXML(), used by children to write state specific to them to project files.

Reimplemented from QgsMapLayer.

Definition at line 122 of file qgsgrouplayer.cpp.

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

• /build/qgis-3.34.0+99sid/src/core/qgsgrouplayer.h
• /build/qgis-3.34.0+99sid/src/core/qgsgrouplayer.cpp