This class tracks map layers that are currently loaded and provides various methods to retrieve matching layers from the registry. More...

#include <qgsmaplayerregistry.h>

Inheritance diagram for QgsMapLayerRegistry:

[legend]

Signals
void	layerRemoved (const QString &theLayerId)
	Emitted after a layer was removed from the registry. More...

void	layersAdded (const QList< QgsMapLayer *> &theMapLayers)
	Emitted when one or more layers were added to the registry. More...

void	layersRemoved (const QStringList &theLayerIds)
	Emitted after one or more layers were removed from the registry. More...

void	layersWillBeRemoved (const QStringList &theLayerIds)
	Emitted when one or more layers are about to be removed from the registry. More...

void	layersWillBeRemoved (const QList< QgsMapLayer *> &layers)
	Emitted when one or more layers are about to be removed from the registry. More...

void	layerWasAdded (QgsMapLayer *theMapLayer)
	Emitted when a layer was added to the registry. More...

void	layerWillBeRemoved (const QString &theLayerId)
	Emitted when a layer is about to be removed from the registry. More...

void	layerWillBeRemoved (QgsMapLayer *layer)
	Emitted when a layer is about to be removed from the registry. More...

void	legendLayersAdded (const QList< QgsMapLayer *> &theMapLayers)
	Emitted, when a layer was added to the registry and the legend. More...

void	removeAll ()
	Emitted when all layers are removed, before layersWillBeRemoved() and layerWillBeRemoved() signals are emitted. More...

Public Member Functions
	~QgsMapLayerRegistry ()

QgsMapLayer *	addMapLayer (QgsMapLayer *theMapLayer, bool addToLegend=true, bool takeOwnership=true)
	Add a layer to the map of loaded layers. More...

QList< QgsMapLayer * >	addMapLayers (const QList< QgsMapLayer *> &theMapLayers, bool addToLegend=true, bool takeOwnership=true)
	Add a list of layers to the map of loaded layers. More...

Q_DECL_DEPRECATED void	clearAllLayerCaches ()
	Clears all layer caches, resetting them to zero and freeing up any memory they may have been using. More...

int	count () const
	Returns the number of registered layers. More...

template<typename T >
QVector< T >	layers () const
	Returns a list of registered map layers with a specified layer type. More...

QgsMapLayer *	mapLayer (const QString &theLayerId) const
	Retrieve a pointer to a registered layer by layer ID. More...

QMap< QString, QgsMapLayer * >	mapLayers () const
	Returns a map of all registered layers by layer ID. More...

QList< QgsMapLayer * >	mapLayersByName (const QString &layerName) const
	Retrieve a list of matching registered layers by layer name. More...

void	reloadAllLayers ()
	Reload all registered layer's provider data caches, synchronising the layer with any changes in the datasource. More...

void	removeAllMapLayers ()
	Removes all registered layers. More...

void	removeMapLayer (const QString &theLayerId)
	Remove a layer from the registry by layer ID. More...

void	removeMapLayer (QgsMapLayer *layer)
	Remove a layer from the registry. More...

void	removeMapLayers (const QStringList &theLayerIds)
	Remove a set of layers from the registry by layer ID. More...

void	removeMapLayers (const QList< QgsMapLayer *> &layers)
	Remove a set of layers from the registry. More...

Public Member Functions inherited from QObject
	QObject (QObject *parent)

	QObject (QObject parent, const char name)

virtual	~QObject ()

bool	blockSignals (bool block)

QObject *	child (const char objName, const char inheritsClass, bool recursiveSearch) const

const QObjectList &	children () const

const char *	className () const

bool	connect (const QObject sender, const char signal, const char *method, Qt::ConnectionType type) const

void	deleteLater ()

void	destroyed (QObject *obj)

bool	disconnect (const QObject receiver, const char method)

bool	disconnect (const char signal, const QObject receiver, const char *method)

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QByteArray >	dynamicPropertyNames () const

virtual bool	event (QEvent *e)

virtual bool	eventFilter (QObject watched, QEvent event)

T	findChild (const QString &name) const

QList< T >	findChildren (const QRegExp &regExp) const

QList< T >	findChildren (const QString &name) const

bool	inherits (const char *className) const

void	insertChild (QObject *object)

void	installEventFilter (QObject *filterObj)

bool	isA (const char *className) const

bool	isWidgetType () const

void	killTimer (int id)

virtual const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

const char *	name () const

const char *	name (const char *defaultName) const

QString	objectName () const

QObject *	parent () const

QVariant	property (const char *name) const

void	removeChild (QObject *object)

void	removeEventFilter (QObject *obj)

void	setName (const char *name)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const char *name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval)

QThread *	thread () const

Static Public Member Functions
static QgsMapLayerRegistry *	instance ()
	Returns the instance pointer, creating the object on the first call. More...

Static Public Member Functions inherited from QObject
bool	connect (const QObject sender, const char signal, const QObject receiver, const char method, Qt::ConnectionType type)

bool	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type)

bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char method)

bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method)

QString	tr (const char sourceText, const char disambiguation, int n)

QString	trUtf8 (const char sourceText, const char disambiguation, int n)

Additional Inherited Members
Protected Member Functions inherited from QObject
bool	checkConnectArgs (const char signal, const QObject object, const char *method)

virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const char *signal)

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const char *signal)

int	receivers (const char *signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Static Protected Member Functions inherited from QObject
QByteArray	normalizeSignalSlot (const char *signalSlot)

Properties inherited from QObject
	objectName

Detailed Description

This class tracks map layers that are currently loaded and provides various methods to retrieve matching layers from the registry.

Definition at line 34 of file qgsmaplayerregistry.h.

Constructor & Destructor Documentation

◆ ~QgsMapLayerRegistry()

QgsMapLayerRegistry::~QgsMapLayerRegistry ( )

Definition at line 35 of file qgsmaplayerregistry.cpp.

Member Function Documentation

◆ addMapLayer()

QgsMapLayer * QgsMapLayerRegistry::addMapLayer	(	QgsMapLayer *	theMapLayer,
		bool	addToLegend = `true`,
		bool	takeOwnership = `true`
	)

Add a layer to the map of loaded layers.

The layersAdded() and layerWasAdded() signals will always be emitted. The legendLayersAdded() signal is emitted only if addToLegend is true. If you are adding multiple layers at once, you should use addMapLayers() instead.

Parameters

theMapLayer	A layer to add to the registry
addToLegend	If true (by default), the layer will be added to the legend and to the main canvas. If you have a private layer you can set this parameter to false to hide it.
takeOwnership	Ownership will be transferred to the layer registry. If you specify false here you have take care of deleting the layer yourself. Not available in python.

Returns: nullptr if unable to add layer, otherwise pointer to newly added layer

See also: addMapLayers

Note: As a side-effect QgsProject is made dirty.; Use addMapLayers if adding more than one layer at a time; takeOwnership is not available in the Python bindings - the registry will always take ownership

See also: addMapLayers()

Definition at line 100 of file qgsmaplayerregistry.cpp.

◆ addMapLayers()

QList< QgsMapLayer * > QgsMapLayerRegistry::addMapLayers	(	const QList< QgsMapLayer *> &	theMapLayers,
		bool	addToLegend = `true`,
		bool	takeOwnership = `true`
	)

Add a list of layers to the map of loaded layers.

The layersAdded() and layerWasAdded() signals will always be emitted. The legendLayersAdded() signal is emitted only if addToLegend is true.

Parameters

theMapLayers	A list of layer which should be added to the registry
addToLegend	If true (by default), the layers will be added to the legend and to the main canvas. If you have a private layer you can set this parameter to false to hide it.
takeOwnership	Ownership will be transferred to the layer registry. If you specify false here you have take care of deleting the layers yourself. Not available in python.

Returns: a list of the map layers that were added successfully. If a layer is invalid, or already exists in the registry, it will not be part of the returned QList.

Note: As a side-effect QgsProject is made dirty.; takeOwnership is not available in the Python bindings - the registry will always take ownership; added in QGIS 1.8

See also: addMapLayer()

Definition at line 63 of file qgsmaplayerregistry.cpp.

◆ clearAllLayerCaches()

Q_DECL_DEPRECATED void QgsMapLayerRegistry::clearAllLayerCaches ( )

inline

Clears all layer caches, resetting them to zero and freeing up any memory they may have been using.

Layer caches are used to speed up rendering in certain situations see ticket #1974 for more details.

Deprecated:: since 2.4 - does nothing

Definition at line 239 of file qgsmaplayerregistry.h.

◆ count()

int QgsMapLayerRegistry::count ( ) const

Returns the number of registered layers.

Definition at line 40 of file qgsmaplayerregistry.cpp.

◆ instance()

QgsMapLayerRegistry * QgsMapLayerRegistry::instance ( )

static

Returns the instance pointer, creating the object on the first call.

Definition at line 25 of file qgsmaplayerregistry.cpp.

◆ layerRemoved

void QgsMapLayerRegistry::layerRemoved ( const QString & theLayerId )

signal

Emitted after a layer was removed from the registry.

Parameters

theLayerId The ID of the layer removed.

Note: Consider using layersRemoved() instead

See also: layerWillBeRemoved()

◆ layers()

template<typename T >

QVector<T> QgsMapLayerRegistry::layers ( ) const

inline

Returns a list of registered map layers with a specified layer type.

Example:

QVector<QgsVectorLayer*> vectorLayers = QgsMapLayerRegistry::instance()->layers<QgsVectorLayer*>();

Note: not available in Python bindings; added in QGIS 2.16

See also: mapLayers()

Definition at line 83 of file qgsmaplayerregistry.h.

◆ layersAdded

void QgsMapLayerRegistry::layersAdded ( const QList< QgsMapLayer *> & theMapLayers )

signal

Emitted when one or more layers were added to the registry.

This signal is also emitted for layers added to the registry, but not to the legend.

Parameters

theMapLayers List of layers which have been added.

See also: legendLayersAdded(); layerWasAdded()

◆ layersRemoved

void QgsMapLayerRegistry::layersRemoved ( const QStringList & theLayerIds )

signal

Emitted after one or more layers were removed from the registry.

Parameters

theLayerIds A list of IDs of the layers which were removed.

See also: layersWillBeRemoved()

◆ layersWillBeRemoved [1/2]

void QgsMapLayerRegistry::layersWillBeRemoved ( const QStringList & theLayerIds )

signal

Emitted when one or more layers are about to be removed from the registry.

Parameters

theLayerIds A list of IDs for the layers which are to be removed.

See also: layerWillBeRemoved(); layersRemoved()

◆ layersWillBeRemoved [2/2]

void QgsMapLayerRegistry::layersWillBeRemoved ( const QList< QgsMapLayer *> & layers )

signal

Emitted when one or more layers are about to be removed from the registry.

Parameters

layers A list of layers which are to be removed.

See also: layerWillBeRemoved(); layersRemoved()

◆ layerWasAdded

void QgsMapLayerRegistry::layerWasAdded ( QgsMapLayer * theMapLayer )

signal

Emitted when a layer was added to the registry.

Parameters

theMapLayer The ID of the layer which has been added.

Note: Consider using layersAdded() instead

See also: layersAdded()

◆ layerWillBeRemoved [1/2]

void QgsMapLayerRegistry::layerWillBeRemoved ( const QString & theLayerId )

signal

Emitted when a layer is about to be removed from the registry.

Parameters

theLayerId The ID of the layer to be removed.

Note: Consider using layersWillBeRemoved() instead

See also: layersWillBeRemoved(); layerRemoved()

◆ layerWillBeRemoved [2/2]

void QgsMapLayerRegistry::layerWillBeRemoved ( QgsMapLayer * layer )

signal

Emitted when a layer is about to be removed from the registry.

Parameters

layer The layer to be removed.

Note: Consider using layersWillBeRemoved() instead

See also: layersWillBeRemoved(); layerRemoved()

◆ legendLayersAdded

void QgsMapLayerRegistry::legendLayersAdded ( const QList< QgsMapLayer *> & theMapLayers )

signal

Emitted, when a layer was added to the registry and the legend.

Layers can also be private layers, which are signalled by layersAdded() and layerWasAdded() but will not be advertised by this signal.

Parameters

theMapLayers List of QgsMapLayers which were added to the legend.

◆ mapLayer()

QgsMapLayer * QgsMapLayerRegistry::mapLayer ( const QString & theLayerId ) const

Retrieve a pointer to a registered layer by layer ID.

Parameters

theLayerId ID of layer to retrieve

Returns: matching layer, or nullptr if no matching layer found

See also: mapLayersByName(); mapLayers()

Definition at line 45 of file qgsmaplayerregistry.cpp.

◆ mapLayers()

QMap< QString, QgsMapLayer * > QgsMapLayerRegistry::mapLayers ( ) const

Returns a map of all registered layers by layer ID.

See also: mapLayer(); mapLayersByName(); layers()

Definition at line 199 of file qgsmaplayerregistry.cpp.

◆ mapLayersByName()

QList< QgsMapLayer * > QgsMapLayerRegistry::mapLayersByName ( const QString & layerName ) const

Retrieve a list of matching registered layers by layer name.

Parameters

layerName name of layers to match

Returns: list of matching layers

See also: mapLayer(); mapLayers()

Definition at line 50 of file qgsmaplayerregistry.cpp.

◆ reloadAllLayers()

void QgsMapLayerRegistry::reloadAllLayers ( )

Reload all registered layer's provider data caches, synchronising the layer with any changes in the datasource.

See also: QgsMapLayer::reload()

Definition at line 180 of file qgsmaplayerregistry.cpp.

◆ removeAll

void QgsMapLayerRegistry::removeAll ( )

signal

Emitted when all layers are removed, before layersWillBeRemoved() and layerWillBeRemoved() signals are emitted.

The layersWillBeRemoved() and layerWillBeRemoved() signals will still be emitted following this signal. You can use this signal to do easy (and fast) cleanup.

◆ removeAllMapLayers()

void QgsMapLayerRegistry::removeAllMapLayers ( )

Removes all registered layers.

If the registry has ownership of any layers these layers will also be deleted.

Note: As a side-effect the QgsProject instance is marked dirty.; Calling this method will cause the removeAll() signal to be emitted.

See also: removeMapLayer(); removeMapLayers()

Definition at line 171 of file qgsmaplayerregistry.cpp.

◆ removeMapLayer() [1/2]

void QgsMapLayerRegistry::removeMapLayer ( const QString & theLayerId )

Remove a layer from the registry by layer ID.

The specified layer will be removed from the registry. If the registry has ownership of the layer then it will also be deleted.

Parameters

theLayerId ID of the layer to remove

Note: As a side-effect the QgsProject instance is marked dirty.

See also: removeMapLayers(); removeAllMapLayers()

Definition at line 160 of file qgsmaplayerregistry.cpp.

◆ removeMapLayer() [2/2]

void QgsMapLayerRegistry::removeMapLayer ( QgsMapLayer * layer )

Remove a layer from the registry.

The specified layer will be removed from the registry. If the registry has ownership of the layer then it will also be deleted.

Parameters

layer The layer to remove. Null pointers are ignored.

Note: As a side-effect the QgsProject instance is marked dirty.

See also: removeMapLayers(); removeAllMapLayers()

Definition at line 165 of file qgsmaplayerregistry.cpp.

◆ removeMapLayers() [1/2]

void QgsMapLayerRegistry::removeMapLayers ( const QStringList & theLayerIds )

Remove a set of layers from the registry by layer ID.

The specified layers will be removed from the registry. If the registry has ownership of any layers these layers will also be deleted.

Parameters

theLayerIds list of IDs of the layers to remove

Note: As a side-effect the QgsProject instance is marked dirty.; added in QGIS 1.8

See also: removeMapLayer(); removeAllMapLayers()

Definition at line 109 of file qgsmaplayerregistry.cpp.

◆ removeMapLayers() [2/2]

void QgsMapLayerRegistry::removeMapLayers ( const QList< QgsMapLayer *> & layers )

Remove a set of layers from the registry.

The specified layers will be removed from the registry. If the registry has ownership of any layers these layers will also be deleted.

Parameters

layers A list of layers to remove. Null pointers are ignored.

Note: As a side-effect the QgsProject instance is marked dirty.

See also: removeMapLayer(); removeAllMapLayers()

Definition at line 120 of file qgsmaplayerregistry.cpp.

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

/tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsmaplayerregistry.h
/tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsmaplayerregistry.cpp

Signals

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ~QgsMapLayerRegistry()

Member Function Documentation

◆ addMapLayer()

◆ addMapLayers()

◆ clearAllLayerCaches()

◆ count()

◆ instance()

◆ layerRemoved

◆ layers()

◆ layersAdded

◆ layersRemoved

◆ layersWillBeRemoved [1/2]

◆ layersWillBeRemoved [2/2]

◆ layerWasAdded

◆ layerWillBeRemoved [1/2]

◆ layerWillBeRemoved [2/2]

◆ legendLayersAdded

◆ mapLayer()

◆ mapLayers()

◆ mapLayersByName()

◆ reloadAllLayers()

◆ removeAll

◆ removeAllMapLayers()

◆ removeMapLayer() [1/2]

◆ removeMapLayer() [2/2]

◆ removeMapLayers() [1/2]

◆ removeMapLayers() [2/2]