Layer tree node points to a map layer. More...

#include <qgslayertreelayer.h>

Inheritance diagram for QgsLayerTreeLayer:

[legend]

Public Types
enum	LegendNodesSplitBehavior { UseDefaultLegendSetting , AllowSplittingLegendNodesOverMultipleColumns , PreventSplittingLegendNodesOverMultipleColumns }
	Legend node column split behavior. More...

Public Types inherited from QgsLayerTreeNode
enum	NodeType { NodeGroup , NodeLayer }
	Enumeration of possible tree node types. More...

Signals
void	layerLoaded ()
	Emitted when a previously unavailable layer got loaded.

void	layerWillBeUnloaded ()
	Emitted when a previously available layer got unloaded (from layer registry).

Signals inherited from QgsLayerTreeNode
void	addedChildren (QgsLayerTreeNode *node, int indexFrom, int indexTo)
	Emitted when one or more nodes have been added to a node within the tree.

void	customPropertyChanged (QgsLayerTreeNode *node, const QString &key)
	Emitted when a custom property of a node within the tree has been changed or removed.

void	expandedChanged (QgsLayerTreeNode *node, bool expanded)
	Emitted when the collapsed/expanded state of a node within the tree has been changed.

void	nameChanged (QgsLayerTreeNode *node, QString name)
	Emitted when the name of the node is changed.

void	removedChildren (QgsLayerTreeNode *node, int indexFrom, int indexTo)
	Emitted when one or more nodes has been removed from a node within the tree.

void	visibilityChanged (QgsLayerTreeNode *node)
	Emitted when check state of a node within the tree has been changed.

void	willAddChildren (QgsLayerTreeNode *node, int indexFrom, int indexTo)
	Emitted when one or more nodes will be added to a node within the tree.

void	willRemoveChildren (QgsLayerTreeNode *node, int indexFrom, int indexTo)
	Emitted when one or more nodes will be removed from a node within the tree.

Public Member Functions
	QgsLayerTreeLayer (const QgsLayerTreeLayer &other)

	QgsLayerTreeLayer (const QString &layerId, const QString &name=QString(), const QString &source=QString(), const QString &provider=QString())
	Constructor for QgsLayerTreeLayer using weak references to layer ID, name, public source, and provider key.

	QgsLayerTreeLayer (QgsMapLayer *layer)

QgsLayerTreeLayer *	clone () const override
	Create a copy of the node. Returns new instance.

QString	dump () const override
	Returns string with layer tree structure. For debug purposes only.

QString	labelExpression () const
	Returns the expression member of the LayerTreeNode.

QgsMapLayer *	layer () const
	Returns the map layer associated with this node.

QString	layerId () const
	Returns the ID for the map layer associated with this node.

LegendNodesSplitBehavior	legendSplitBehavior () const
	Returns the column split behavior for the node.

QString	name () const override
	Returns the layer's name.

QgsLegendPatchShape	patchShape () const
	Returns the symbol patch shape to use when rendering the legend node symbol.

QSizeF	patchSize () const
	Returns the user (overridden) size for the legend node.

void	resolveReferences (const QgsProject *project, bool looseMatching=false) override
	Resolves reference to layer from stored layer ID (if it has not been resolved already)

void	setLabelExpression (const QString &expression)
	set the expression to evaluate

void	setLegendSplitBehavior (LegendNodesSplitBehavior behavior)
	Sets the column split behavior for the node.

void	setName (const QString &n) override
	Sets the layer's name.

void	setPatchShape (const QgsLegendPatchShape &shape)
	Sets the symbol patch shape to use when rendering the legend node symbol.

void	setPatchSize (QSizeF size)
	Sets the user (overridden) size for the legend node.

void	setUseLayerName (bool use=true)
	Uses the layer's name if use is `true`, or the name manually set if `false`.

bool	useLayerName () const
	Returns whether the layer's name is used, or the name manually set.

void	writeXml (QDomElement &parentElement, const QgsReadWriteContext &context) override
	Write layer tree to XML.

Public Member Functions inherited from QgsLayerTreeNode
	~QgsLayerTreeNode () override

QList< QgsLayerTreeNode * >	abandonChildren ()
	Removes the children, disconnect all the forwarded and external signals and sets their parent to `nullptr`.

QList< QgsMapLayer * >	checkedLayers () const
	Returns a list of any checked layers which belong to this node or its children.

QList< QgsLayerTreeNode * >	children ()
	Gets list of children of the node. Children are owned by the parent.

QList< QgsLayerTreeNode * >	children () const
	Gets list of children of the node. Children are owned by the parent.

QStringList	customProperties () const
	Returns list of keys stored in custom properties.

QVariant	customProperty (const QString &key, const QVariant &defaultValue=QVariant()) const
	Read a custom property from layer. Properties are stored in a map and saved in project file.

int	depth () const
	Returns the depth of this node, i.e.

bool	isExpanded () const
	Returns whether the node should be shown as expanded or collapsed in GUI.

bool	isItemVisibilityCheckedRecursive () const
	Returns whether this node is checked and all its children.

bool	isItemVisibilityUncheckedRecursive () const
	Returns whether this node is unchecked and all its children.

bool	isVisible () const
	Returns whether a node is really visible (ie checked and all its ancestors checked as well)

bool	itemVisibilityChecked () const
	Returns whether a node is checked (independently of its ancestors or children)

NodeType	nodeType () const
	Find out about type of the node. It is usually shorter to use convenience functions from QgsLayerTree namespace for that.

QgsLayerTreeNode *	parent ()
	Gets pointer to the parent. If parent is `nullptr`, the node is a root node.

void	removeCustomProperty (const QString &key)
	Remove a custom property from layer. Properties are stored in a map and saved in project file.

void	setCustomProperty (const QString &key, const QVariant &value)
	Sets a custom property for the node. Properties are stored in a map and saved in project file.

void	setExpanded (bool expanded)
	Sets whether the node should be shown as expanded or collapsed in GUI.

void	setItemVisibilityChecked (bool checked)
	Check or uncheck a node (independently of its ancestors or children)

void	setItemVisibilityCheckedParentRecursive (bool checked)
	Check or uncheck a node and all its parents.

virtual void	setItemVisibilityCheckedRecursive (bool checked)
	Check or uncheck a node and all its children (taking into account exclusion rules)

bool	takeChild (QgsLayerTreeNode *node)
	Remove a child from a node.

Static Public Member Functions
static QgsLayerTreeLayer *	readXml (QDomElement &element, const QgsProject *project, const QgsReadWriteContext &context)
	Read layer node from XML.

static QgsLayerTreeLayer *	readXml (QDomElement &element, const QgsReadWriteContext &context)
	Read layer node from XML.

Static Public Member Functions inherited from QgsLayerTreeNode
static QgsLayerTreeNode *	readXml (QDomElement &element, const QgsProject *project)
	Read layer tree from XML.

static QgsLayerTreeNode *	readXml (QDomElement &element, const QgsReadWriteContext &context)
	Read layer tree from XML.

Protected Member Functions
void	attachToLayer ()

Protected Member Functions inherited from QgsLayerTreeNode
	QgsLayerTreeNode (const QgsLayerTreeNode &other)

	QgsLayerTreeNode (NodeType t, bool checked=true)
	Constructor.

void	insertChildrenPrivate (int index, const QList< QgsLayerTreeNode * > &nodes)
	Low-level insertion of children to the node. The children must not have any parent yet!

virtual void	makeOrphan ()
	Sets parent to `nullptr` and disconnects all external and forwarded signals.

void	readCommonXml (QDomElement &element)
	Read common XML elements.

void	removeChildrenPrivate (int from, int count, bool destroy=true)
	Low-level removal of children from the node.

void	writeCommonXml (QDomElement &element)
	Write common XML elements.

Protected Attributes
QString	mLabelExpression
	Expression to evaluate in the legend.

QString	mLayerName
	Layer name - only used if layer does not exist or if mUseLayerName is false.

QgsMapLayerRef	mRef
	Weak reference to the layer (or just it's ID if the reference is not resolved yet)

bool	mUseLayerName = true

Protected Attributes inherited from QgsLayerTreeNode
bool	mChecked

QList< QgsLayerTreeNode * >	mChildren
	list of children - node is responsible for their deletion

bool	mExpanded
	whether the node should be shown in GUI as expanded

NodeType	mNodeType
	type of the node - determines which subclass is used

QgsLayerTreeNode *	mParent = nullptr
	pointer to the parent node - `nullptr` in case of root node

QgsObjectCustomProperties	mProperties
	custom properties attached to the node

Detailed Description

Layer tree node points to a map layer.

The node can exist also without a valid instance of a layer (just ID). That means the referenced layer does not need to be loaded in order to use it in layer tree. In such case, resolveReferences() method can be called once the layer is loaded.

A map layer is supposed to be present in one layer tree just once. It is however possible that temporarily a layer exists in one tree more than just once, e.g. while reordering items with drag and drop.

Definition at line 42 of file qgslayertreelayer.h.

Member Enumeration Documentation

◆ LegendNodesSplitBehavior

enum QgsLayerTreeLayer::LegendNodesSplitBehavior

Legend node column split behavior.

Since: QGIS 3.14

Enumerator
UseDefaultLegendSetting	Inherit default legend column splitting setting.
AllowSplittingLegendNodesOverMultipleColumns	Allow splitting node's legend nodes across multiple columns.
PreventSplittingLegendNodesOverMultipleColumns	Prevent splitting node's legend nodes across multiple columns.

Definition at line 192 of file qgslayertreelayer.h.

Constructor & Destructor Documentation

◆ QgsLayerTreeLayer() [1/3]

QgsLayerTreeLayer::QgsLayerTreeLayer ( QgsMapLayer * layer )

explicit

Definition at line 25 of file qgslayertreelayer.cpp.

◆ QgsLayerTreeLayer() [2/3]

QgsLayerTreeLayer::QgsLayerTreeLayer ( const QgsLayerTreeLayer & other )

Definition at line 40 of file qgslayertreelayer.cpp.

◆ QgsLayerTreeLayer() [3/3]

QgsLayerTreeLayer::QgsLayerTreeLayer	(	const QString &	layerId,
		const QString &	name = `QString()`,
		const QString &	source = `QString()`,
		const QString &	provider = `QString()`
	)

explicit

Constructor for QgsLayerTreeLayer using weak references to layer ID, name, public source, and provider key.

Definition at line 33 of file qgslayertreelayer.cpp.

Member Function Documentation

◆ attachToLayer()

void QgsLayerTreeLayer::attachToLayer ( )

protected

Definition at line 72 of file qgslayertreelayer.cpp.

◆ clone()

QgsLayerTreeLayer * QgsLayerTreeLayer::clone ( ) const

overridevirtual

Create a copy of the node. Returns new instance.

Implements QgsLayerTreeNode.

Definition at line 192 of file qgslayertreelayer.cpp.

◆ dump()

QString QgsLayerTreeLayer::dump ( ) const

overridevirtual

Returns string with layer tree structure. For debug purposes only.

Implements QgsLayerTreeNode.

Definition at line 187 of file qgslayertreelayer.cpp.

◆ labelExpression()

QString QgsLayerTreeLayer::labelExpression ( ) const

inline

Returns the expression member of the LayerTreeNode.

Since: QGIS 3.10

Definition at line 147 of file qgslayertreelayer.h.

◆ layer()

QgsMapLayer * QgsLayerTreeLayer::layer ( ) const

inline

Returns the map layer associated with this node.

Warning: This can be (and often is!) nullptr, e.g. in the case of a layer node representing a layer which has not yet been fully loaded into a project, or a layer node representing a layer with an invalid data source. The returned pointer must ALWAYS be checked to avoid dereferencing nullptr.

See also: layerId()

Definition at line 81 of file qgslayertreelayer.h.

◆ layerId()

QString QgsLayerTreeLayer::layerId ( ) const

inline

Returns the ID for the map layer associated with this node.

See also: layer()

Definition at line 70 of file qgslayertreelayer.h.

◆ layerLoaded

void QgsLayerTreeLayer::layerLoaded ( )

signal

Emitted when a previously unavailable layer got loaded.

◆ layerWillBeUnloaded

void QgsLayerTreeLayer::layerWillBeUnloaded ( )

signal

Emitted when a previously available layer got unloaded (from layer registry).

◆ legendSplitBehavior()

LegendNodesSplitBehavior QgsLayerTreeLayer::legendSplitBehavior ( ) const

inline

Returns the column split behavior for the node.

This value controls how legend nodes belonging the to layer may be split over multiple columns in legends.

See also: setLegendSplitBehavior()

Since: QGIS 3.14

Definition at line 207 of file qgslayertreelayer.h.

◆ name()

QString QgsLayerTreeLayer::name ( ) const

overridevirtual

Returns the layer's name.

See also: setName()

Implements QgsLayerTreeNode.

Definition at line 82 of file qgslayertreelayer.cpp.

◆ patchShape()

QgsLegendPatchShape QgsLayerTreeLayer::patchShape ( ) const

Returns the symbol patch shape to use when rendering the legend node symbol.

See also: setPatchShape()

Since: QGIS 3.14

Definition at line 231 of file qgslayertreelayer.cpp.

◆ patchSize()

QSizeF QgsLayerTreeLayer::patchSize ( ) const

inline

Returns the user (overridden) size for the legend node.

If either the width or height are non-zero, they will be used when rendering the legend node instead of the default symbol width or height from QgsLegendSettings.

See also: setPatchSize()

Since: QGIS 3.14

Definition at line 174 of file qgslayertreelayer.h.

◆ readXml() [1/2]

QgsLayerTreeLayer * QgsLayerTreeLayer::readXml	(	QDomElement &	element,
		const QgsProject *	project,
		const QgsReadWriteContext &	context
	)

static

Read layer node from XML.

Returns new instance. Also resolves textual references to layers from the project (calls resolveReferences() internally).

Definition at line 145 of file qgslayertreelayer.cpp.

◆ readXml() [2/2]

QgsLayerTreeLayer * QgsLayerTreeLayer::readXml	(	QDomElement &	element,
		const QgsReadWriteContext &	context
	)

static

Read layer node from XML.

Returns new instance. Does not resolve textual references to layers. Call resolveReferences() afterwards to do it.

Definition at line 105 of file qgslayertreelayer.cpp.

◆ resolveReferences()

void QgsLayerTreeLayer::resolveReferences	(	const QgsProject *	project,
		bool	looseMatching = `false`
	)

overridevirtual

Resolves reference to layer from stored layer ID (if it has not been resolved already)

Implements QgsLayerTreeNode.

Definition at line 51 of file qgslayertreelayer.cpp.

◆ setLabelExpression()

void QgsLayerTreeLayer::setLabelExpression ( const QString & expression )

set the expression to evaluate

Since: QGIS 3.10

Definition at line 226 of file qgslayertreelayer.cpp.

◆ setLegendSplitBehavior()

void QgsLayerTreeLayer::setLegendSplitBehavior ( LegendNodesSplitBehavior behavior )

inline

Sets the column split behavior for the node.

This value controls how legend nodes belonging the to layer may be split over multiple columns in legends.

See also: legendSplitBehavior()

Since: QGIS 3.14

Definition at line 217 of file qgslayertreelayer.h.

◆ setName()

void QgsLayerTreeLayer::setName ( const QString & n )

overridevirtual

Sets the layer's name.

See also: name()

Implements QgsLayerTreeNode.

Definition at line 87 of file qgslayertreelayer.cpp.

◆ setPatchShape()

void QgsLayerTreeLayer::setPatchShape ( const QgsLegendPatchShape & shape )

Sets the symbol patch shape to use when rendering the legend node symbol.

See also: patchShape()

Since: QGIS 3.14

Definition at line 236 of file qgslayertreelayer.cpp.

◆ setPatchSize()

void QgsLayerTreeLayer::setPatchSize ( QSizeF size )

inline

Sets the user (overridden) size for the legend node.

If either the width or height are non-zero, they will be used when rendering the legend node instead of the default symbol width or height from QgsLegendSettings.

See also: patchSize()

Since: QGIS 3.14

Definition at line 185 of file qgslayertreelayer.h.

◆ setUseLayerName()

void QgsLayerTreeLayer::setUseLayerName ( bool use = true )

Uses the layer's name if use is true, or the name manually set if false.

Since: QGIS 3.8

Definition at line 210 of file qgslayertreelayer.cpp.

◆ useLayerName()

bool QgsLayerTreeLayer::useLayerName ( ) const

Returns whether the layer's name is used, or the name manually set.

Since: QGIS 3.8

Definition at line 215 of file qgslayertreelayer.cpp.

◆ writeXml()

void QgsLayerTreeLayer::writeXml	(	QDomElement &	parentElement,
		const QgsReadWriteContext &	context
	)

overridevirtual

Write layer tree to XML.

Implements QgsLayerTreeNode.

Definition at line 153 of file qgslayertreelayer.cpp.

Member Data Documentation

◆ mLabelExpression

QString QgsLayerTreeLayer::mLabelExpression

protected

Expression to evaluate in the legend.

Definition at line 239 of file qgslayertreelayer.h.

◆ mLayerName

QString QgsLayerTreeLayer::mLayerName

protected

Layer name - only used if layer does not exist or if mUseLayerName is false.

Definition at line 237 of file qgslayertreelayer.h.

◆ mRef

QgsMapLayerRef QgsLayerTreeLayer::mRef

protected

Weak reference to the layer (or just it's ID if the reference is not resolved yet)

Definition at line 235 of file qgslayertreelayer.h.

◆ mUseLayerName

bool QgsLayerTreeLayer::mUseLayerName = true

protected

Definition at line 242 of file qgslayertreelayer.h.

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

/build/qgis-3.41.0+git20241201+3c143d501a8+99sid/src/core/layertree/qgslayertreelayer.h
/build/qgis-3.41.0+git20241201+3c143d501a8+99sid/src/core/layertree/qgslayertreelayer.cpp

Public Types

Signals

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Enumeration Documentation

◆ LegendNodesSplitBehavior

Constructor & Destructor Documentation

◆ QgsLayerTreeLayer() [1/3]

◆ QgsLayerTreeLayer() [2/3]

◆ QgsLayerTreeLayer() [3/3]

Member Function Documentation

◆ attachToLayer()

◆ clone()

◆ dump()

◆ labelExpression()

◆ layer()

◆ layerId()

◆ layerLoaded

◆ layerWillBeUnloaded

◆ legendSplitBehavior()

◆ name()

◆ patchShape()

◆ patchSize()

◆ readXml() [1/2]

◆ readXml() [2/2]

◆ resolveReferences()

◆ setLabelExpression()

◆ setLegendSplitBehavior()

◆ setName()

◆ setPatchShape()

◆ setPatchSize()

◆ setUseLayerName()

◆ useLayerName()

◆ writeXml()

Member Data Documentation

◆ mLabelExpression

◆ mLayerName

◆ mRef

◆ mUseLayerName