QgsMapLayerRegistry Class Reference
[QGIS core library]

This class tracks map layers that are currently loaded and provides a means to fetch a pointer to a map layer and delete it. More...

#include <qgsmaplayerregistry.h>

Collaboration diagram for QgsMapLayerRegistry:

[legend]

List of all members.

Signals

void layerWillBeRemoved (QString theLayerId)

emitted when a layer is removed from the registry connected to main map canvas and overview map canvas remove()

void layerWasAdded (QgsMapLayer *theMapLayer)

emitted when a layer is added to the registry connected to main map canvas and overview map canvas addLayer()

void removedAll ()

emitted when ALL layers are removed at once This could have been implemented by iteratively signalling layerWillBeRemoved() for each layer as it is removed.

Public Member Functions

int count ()

~QgsMapLayerRegistry ()

QgsMapLayer * mapLayer (QString theLayerId)

Retrieve a pointer to a loaded plugin by id.

QMap< QString, QgsMapLayer * > & mapLayers ()

Retrieve the mapLayers collection (mainly intended for use by projectio).

QgsMapLayer * addMapLayer (QgsMapLayer *theMapLayer, bool theEmitSignal=true)

Add a layer to the map of loaded layers.

void removeMapLayer (QString theLayerId, bool theEmitSignal=true)

Remove a layer from qgis.

void removeAllMapLayers ()

Remove all registered layers.

void clearAllLayerCaches ()

void reloadAllLayers ()

Reload all provider data caches (currently used for WFS and WMS providers).

Static Public Member Functions

static QgsMapLayerRegistry * instance ()

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

Protected Member Functions

QgsMapLayerRegistry (QObject *parent=0)

protected constructor

Private Member Functions

void connectNotify (const char *signal)

debugging member invoked when a connect() is made to this object

Private Attributes

QMap< QString, QgsMapLayer * > mMapLayers

Static Private Attributes

static QgsMapLayerRegistry * mInstance = 0

Detailed Description

This class tracks map layers that are currently loaded and provides a means to fetch a pointer to a map layer and delete it.

Definition at line 35 of file qgsmaplayerregistry.h.

Constructor & Destructor Documentation

QgsMapLayerRegistry::~QgsMapLayerRegistry ( )

Definition at line 47 of file qgsmaplayerregistry.cpp.

References removeAllMapLayers().

QgsMapLayerRegistry::QgsMapLayerRegistry ( QObject * parent = 0 ) [protected]

protected constructor

Definition at line 42 of file qgsmaplayerregistry.cpp.

Referenced by instance().

Member Function Documentation

QgsMapLayerRegistry * QgsMapLayerRegistry::instance ( ) [static]

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

Definition at line 29 of file qgsmaplayerregistry.cpp.

References mInstance, and QgsMapLayerRegistry().

Referenced by QgsProject::_getMapLayers(), QgsGeometry::avoidIntersections(), QgsComposerMap::connectUpdateSlot(), QgsComposerMap::containsWMSLayer(), QgsComposerLegend::drawLayerItem(), QgsApplication::exitQgis(), QgsApplication::initQgis(), QgsMapCanvas::layer(), QgsMapCanvas::layers(), QgsQuickPrint::printMap(), QgsComposerAttributeTable::QgsComposerAttributeTable(), QgsLegendModel::QgsLegendModel(), QgsProject::read(), QgsRasterLayer::readFile(), QgsFormAnnotationItem::readXML(), QgsComposerRasterSymbolItem::readXML(), QgsComposerSymbolItem::readXML(), QgsComposerAttributeTable::readXML(), QgsPluginLayerRegistry::removePluginLayerType(), QgsMapRenderer::render(), QgsQuickPrint::scalePointSymbols(), QgsQuickPrint::scaleTextLabels(), QgsVectorLayer::setDataProvider(), QgsLegendModel::setLayerSet(), QgsMapCanvasSnapper::snapToBackgroundLayers(), QgsMapRenderer::updateFullExtent(), QgsLegendModel::updateLayer(), and QgsProject::write().

int QgsMapLayerRegistry::count ( )

Return the number of registered layers.

Definition at line 53 of file qgsmaplayerregistry.cpp.

References mMapLayers.

QgsMapLayer * QgsMapLayerRegistry::mapLayer ( QString theLayerId )

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

Retrieve the mapLayers collection (mainly intended for use by projectio).

Definition at line 143 of file qgsmaplayerregistry.cpp.

References mMapLayers.

Referenced by QgsComposerAttributeTable::QgsComposerAttributeTable(), QgsPluginLayerRegistry::removePluginLayerType(), QgsVectorLayer::setDataProvider(), and QgsProject::write().

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

Add a layer to the map of loaded layers.

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

Note:

As a side-effect QgsProject is made dirty.

Emits signal that layer has been added only if theEmitSignal is true (by default). Not emitting signal is useful when you want to use registry also for layers which won't be used in main map canvas but will be used in a special one

Definition at line 66 of file qgsmaplayerregistry.cpp.

References QgsMapLayer::getLayerID(), QgsMapLayer::isValid(), layerWasAdded(), mMapLayers, and QgsDebugMsg.

Referenced by QgsProject::_getMapLayers(), and QgsProject::read().

void QgsMapLayerRegistry::removeMapLayer	(	QString	theLayerId,
		bool	theEmitSignal = `true`
	)

Remove a layer from qgis.

Note:: As a side-effect QgsProject is made dirty. Any canvases using that layer will need to remove it theEmitSignal - see addMapLayer() The layer being removed is deleted as well as the registry table entry.

Definition at line 94 of file qgsmaplayerregistry.cpp.

References layerWillBeRemoved(), and mMapLayers.

Referenced by QgsPluginLayerRegistry::removePluginLayerType().

void QgsMapLayerRegistry::removeAllMapLayers ( )

Remove all registered layers.

Note:: raises removedAll() As a side-effect QgsProject is made dirty.
The layers are deleted as the registry is cleared!

Definition at line 102 of file qgsmaplayerregistry.cpp.

References layerWillBeRemoved(), mMapLayers, and removedAll().

Referenced by ~QgsMapLayerRegistry().

void QgsMapLayerRegistry::clearAllLayerCaches ( )

Definition at line 120 of file qgsmaplayerregistry.cpp.

References mMapLayers.

Referenced by QgsMapRenderer::render().

void QgsMapLayerRegistry::reloadAllLayers ( )

Reload all provider data caches (currently used for WFS and WMS providers).

Note:: : this method was added in QGIS 1.6

Definition at line 130 of file qgsmaplayerregistry.cpp.

References mMapLayers, and QgsMapLayer::reload().

void QgsMapLayerRegistry::layerWillBeRemoved ( QString theLayerId ) [signal]

emitted when a layer is removed from the registry connected to main map canvas and overview map canvas remove()

Referenced by removeAllMapLayers(), and removeMapLayer().

void QgsMapLayerRegistry::layerWasAdded ( QgsMapLayer * theMapLayer ) [signal]

emitted when a layer is added to the registry connected to main map canvas and overview map canvas addLayer()

Referenced by addMapLayer().

void QgsMapLayerRegistry::removedAll ( ) [signal]

emitted when ALL layers are removed at once This could have been implemented by iteratively signalling layerWillBeRemoved() for each layer as it is removed.

However, this generally causes a cascade of effects that are unnecessary if we're ultimately removing all layers. E.g., removing the legend item corresponding to the layer. Why bother doing that when you're just going to clear everything anyway?

Referenced by removeAllMapLayers().

void QgsMapLayerRegistry::connectNotify ( const char * signal ) [private]

debugging member invoked when a connect() is made to this object

Definition at line 150 of file qgsmaplayerregistry.cpp.

Member Data Documentation

QgsMapLayerRegistry * QgsMapLayerRegistry::mInstance = 0 [static, private]

Definition at line 126 of file qgsmaplayerregistry.h.

Referenced by instance().

QMap<QString, QgsMapLayer*> QgsMapLayerRegistry::mMapLayers [private]

Definition at line 128 of file qgsmaplayerregistry.h.

Referenced by addMapLayer(), clearAllLayerCaches(), count(), mapLayer(), mapLayers(), reloadAllLayers(), removeAllMapLayers(), and removeMapLayer().

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

src/core/qgsmaplayerregistry.h
src/core/qgsmaplayerregistry.cpp


Signals
void	layerWillBeRemoved (QString theLayerId)
	emitted when a layer is removed from the registry connected to main map canvas and overview map canvas remove()
void	layerWasAdded (QgsMapLayer *theMapLayer)
	emitted when a layer is added to the registry connected to main map canvas and overview map canvas addLayer()
void	removedAll ()
	emitted when ALL layers are removed at once This could have been implemented by iteratively signalling layerWillBeRemoved() for each layer as it is removed.
Public Member Functions
int	count ()
	~QgsMapLayerRegistry ()
QgsMapLayer *	mapLayer (QString theLayerId)
	Retrieve a pointer to a loaded plugin by id.
QMap< QString, QgsMapLayer * > &	mapLayers ()
	Retrieve the mapLayers collection (mainly intended for use by projectio).
QgsMapLayer *	addMapLayer (QgsMapLayer *theMapLayer, bool theEmitSignal=true)
	Add a layer to the map of loaded layers.
void	removeMapLayer (QString theLayerId, bool theEmitSignal=true)
	Remove a layer from qgis.
void	removeAllMapLayers ()
	Remove all registered layers.
void	clearAllLayerCaches ()
void	reloadAllLayers ()
	Reload all provider data caches (currently used for WFS and WMS providers).
Static Public Member Functions
static QgsMapLayerRegistry *	instance ()
	Returns the instance pointer, creating the object on the first call.
Protected Member Functions
	QgsMapLayerRegistry (QObject *parent=0)
	protected constructor
Private Member Functions
void	connectNotify (const char *signal)
	debugging member invoked when a connect() is made to this object
Private Attributes
QMap< QString, QgsMapLayer * >	mMapLayers
Static Private Attributes
static QgsMapLayerRegistry *	mInstance = 0

QgsMapLayerRegistry Class Reference [QGIS core library]

Signals

Public Member Functions

Static Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

QgsMapLayerRegistry Class Reference
[QGIS core library]