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:

List of all members.

Signals
void	layersAdded (QList< QgsMapLayer * > theMapLayers)
	Emitted when one or more layers are added to the registry.
void	layersWillBeRemoved (QStringList theLayerIds)
	Emitted when one or more layers are removed from the registry.
void	layerWasAdded (QgsMapLayer *theMapLayer)
	Emitted when a layer is added to the registry.
void	layerWillBeRemoved (QString theLayerId)
	Emitted when a layer is removed from the registry.
void	legendLayersAdded (QList< QgsMapLayer * > theMapLayers)
	Emitted, when a layer is added to the registry and the legend.
void	removeAll ()
	Emitted, when all layers are removed, before layersWillBeRemoved() and layerWillBeRemoved() signals are emitted.
Public Member Functions
	~QgsMapLayerRegistry ()
QgsMapLayer *	addMapLayer (QgsMapLayer *theMapLayer, bool addToLegend=true)
	Add a layer to the map of loaded layers.
QList< QgsMapLayer * >	addMapLayers (QList< QgsMapLayer * > theMapLayers, bool addToLegend=true)
	Add a list of layers to the map of loaded layers.
void	clearAllLayerCaches ()
	Clears all layer caches, resetting them to zero and freeing up any memory they may have been using.
int	count ()
	Return the number of registered layers.
QgsMapLayer *	mapLayer (QString theLayerId)
	Retrieve a pointer to a loaded layer by id.
const QMap< QString, QgsMapLayer * > &	mapLayers ()
	Retrieve the mapLayers collection (mainly intended for use by projection)
QList< QgsMapLayer * >	mapLayersByName (QString layerName)
	Retrieve a pointer to a loaded layer by name.
void	reloadAllLayers ()
	Reload all provider data caches (currently used for WFS and WMS providers)
void	removeAllMapLayers ()
	Remove all registered layers.
void	removeMapLayer (const QString &theLayerId)
	Remove a layer from qgis.
void	removeMapLayers (QStringList theLayerIds)
	Remove a set of layers from the registry.
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 32 of file qgsmaplayerregistry.h.

Constructor & Destructor Documentation

QgsMapLayerRegistry::~QgsMapLayerRegistry ( )

Definition at line 44 of file qgsmaplayerregistry.cpp.

References removeAllMapLayers().

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

protected constructor

Definition at line 39 of file qgsmaplayerregistry.cpp.

Referenced by instance().

Member Function Documentation

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

Add a layer to the map of loaded layers.

The layersAdded() and layersWasAdded() signals will be emitted in any case. The legendLayersAdded() signal 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 you can set this parameter to false to hide it.

Returns:: NULL 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

Definition at line 111 of file qgsmaplayerregistry.cpp.

References addMapLayers().

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

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

The layersAdded() and layersWasAdded() signals will be emitted in any case. The legendLayersAdded() signal 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.

Returns:: QList<QgsMapLayer *> - 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.; Added in QGIS 1.8

Definition at line 74 of file qgsmaplayerregistry.cpp.

References QgsMapLayer::id(), QgsMapLayer::isValid(), layersAdded(), layerWasAdded(), legendLayersAdded(), mMapLayers, and QgsDebugMsg.

Referenced by addMapLayer(), QgsOfflineEditing::copyVectorLayer(), and QgsOfflineEditing::synchronize().

void QgsMapLayerRegistry::clearAllLayerCaches ( )

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.

Note:: Added in QGIS 1.4

Definition at line 149 of file qgsmaplayerregistry.cpp.

References mMapLayers.

Referenced by QgsMapRenderer::render().

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

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

Definition at line 179 of file qgsmaplayerregistry.cpp.

int QgsMapLayerRegistry::count ( )

Return the number of registered layers.

Definition at line 50 of file qgsmaplayerregistry.cpp.

References mMapLayers.

QgsMapLayerRegistry * QgsMapLayerRegistry::instance ( ) [static]

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

Definition at line 26 of file qgsmaplayerregistry.cpp.

References mInstance, and QgsMapLayerRegistry().

Referenced by QgsGeometry::avoidIntersections(), QgsVectorLayerJoinBuffer::cacheJoinLayer(), QgsOfflineEditing::committedFeaturesAdded(), QgsComposerMap::connectUpdateSlot(), QgsComposerMap::containsAdvancedEffects(), QgsComposerMap::containsWMSLayer(), QgsOfflineEditing::convertToOfflineProject(), QgsOfflineEditing::copyVectorLayer(), QgsAttributeEditor::createAttributeEditor(), QgsComposerLegend::drawSymbolItem(), QgsApplication::exitQgis(), QgsApplication::initQgis(), QgsMapCanvas::layer(), QgsMapCanvas::layers(), QgsAttributeTableModel::loadAttributes(), QgsVectorLayer::maximumValue(), QgsVectorLayer::minimumValue(), QgsVectorLayerFeatureIterator::prepareJoins(), QgsComposerAttributeTable::QgsComposerAttributeTable(), QgsLegendModel::QgsLegendModel(), QgsOfflineEditing::QgsOfflineEditing(), QgsVectorLayer::QgsVectorLayer(), QgsHtmlAnnotationItem::readXML(), QgsFormAnnotationItem::readXML(), QgsComposerAttributeTable::readXML(), QgsAtlasComposition::readXML(), QgsVectorLayer::readXml(), QgsMapRenderer::render(), QgsLegendModel::setAutoUpdate(), QgsVectorLayer::setDataProvider(), QgsComposerLayerItem::setDefaultStyle(), QgsLegendModel::setLayerSet(), QgsMapCanvasSnapper::snapToBackgroundLayers(), QgsOfflineEditing::synchronize(), QgsComposerMap::syncLayerSet(), QgsVectorLayer::uniqueValues(), QgsVectorLayerJoinBuffer::updateFields(), QgsMapRenderer::updateFullExtent(), QgsLegendModel::updateLayer(), QgsLegendModel::updateLayerItemText(), QgsLegendModel::updateRasterSymbolItemText(), and QgsLegendModel::updateSymbolV2ItemText().

void QgsMapLayerRegistry::layersAdded ( QList< QgsMapLayer * > theMapLayers ) [signal]

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

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

Parameters:

theMapLayers The layers which have been added

See also:: legendLayersAdded()

Referenced by addMapLayers().

void QgsMapLayerRegistry::layersWillBeRemoved ( QStringList theLayerIds ) [signal]

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

Parameters:

theLayerIds A list of ids of the layers which are removed.

Referenced by removeMapLayers().

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

Emitted when a layer is added to the registry.

Parameters:

theMapLayer The id of the layer which has been added

Note:: Consider using layersAdded() instead

Referenced by addMapLayers().

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

Emitted when a layer is removed from the registry.

Parameters:

theLayerId The id of the layer being removed

Note:: Consider using layersWillBeRemoved() instead

Referenced by removeMapLayers().

void QgsMapLayerRegistry::legendLayersAdded ( QList< QgsMapLayer * > theMapLayers ) [signal]

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

Plugins are allowed to have private layers, which are signalled by layersAdded() and layerWasAdded() but will not be advertised by this signal.

Parameters:

theMapLayers The QgsMapLayers which are added to the legend.

Note:: Added in 2.0

Referenced by addMapLayers().

QgsMapLayer * QgsMapLayerRegistry::mapLayer ( QString theLayerId )

Retrieve a pointer to a loaded layer by id.

Definition at line 55 of file qgsmaplayerregistry.cpp.

References mMapLayers.

Referenced by QgsGeometry::avoidIntersections(), QgsVectorLayerJoinBuffer::cacheJoinLayer(), QgsOfflineEditing::committedFeaturesAdded(), QgsComposerMap::containsAdvancedEffects(), QgsComposerMap::containsWMSLayer(), QgsOfflineEditing::convertToOfflineProject(), QgsAttributeEditor::createAttributeEditor(), QgsComposerLegend::drawSymbolItem(), QgsMapCanvas::layer(), QgsMapCanvas::layers(), QgsAttributeTableModel::loadAttributes(), QgsVectorLayer::maximumValue(), QgsVectorLayer::minimumValue(), QgsVectorLayerFeatureIterator::prepareJoins(), QgsHtmlAnnotationItem::readXML(), QgsFormAnnotationItem::readXML(), QgsComposerAttributeTable::readXML(), QgsMapRenderer::render(), QgsComposerLayerItem::setDefaultStyle(), QgsLegendModel::setLayerSet(), QgsMapCanvasSnapper::snapToBackgroundLayers(), QgsVectorLayer::uniqueValues(), QgsVectorLayerJoinBuffer::updateFields(), QgsMapRenderer::updateFullExtent(), QgsLegendModel::updateLayer(), QgsLegendModel::updateLayerItemText(), QgsLegendModel::updateRasterSymbolItemText(), and QgsLegendModel::updateSymbolV2ItemText().

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

Retrieve the mapLayers collection (mainly intended for use by projection)

Definition at line 172 of file qgsmaplayerregistry.cpp.

References mMapLayers.

Referenced by QgsComposerAttributeTable::QgsComposerAttributeTable(), QgsAtlasComposition::readXML(), QgsVectorLayer::setDataProvider(), QgsOfflineEditing::synchronize(), and QgsComposerMap::syncLayerSet().

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

Retrieve a pointer to a loaded layer by name.

Definition at line 60 of file qgsmaplayerregistry.cpp.

References mMapLayers, and QgsMapLayer::name().

void QgsMapLayerRegistry::reloadAllLayers ( )

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

Note:: Added in QGIS 1.6

Definition at line 159 of file qgsmaplayerregistry.cpp.

References mMapLayers, and QgsMapLayer::reload().

void QgsMapLayerRegistry::removeAll ( ) [signal]

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

You will still get these signals in any case. You can use this signal to do easy (and fast) cleanup.

Note:: Added in 2.0

Referenced by removeAllMapLayers().

void QgsMapLayerRegistry::removeAllMapLayers ( )

Remove all registered layers.

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

Definition at line 139 of file qgsmaplayerregistry.cpp.

References mMapLayers, removeAll(), and removeMapLayers().

Referenced by ~QgsMapLayerRegistry().

void QgsMapLayerRegistry::removeMapLayer ( const QString & theLayerId )

Remove a layer from qgis.

Any canvases using the affected layers will need to remove them

The layer being removed is deleted as well as the registry table entry.

Parameters:

theLayerId The id of the layer to remove

Note:: As a side-effect QgsProject is made dirty.

Definition at line 133 of file qgsmaplayerregistry.cpp.

References removeMapLayers().

void QgsMapLayerRegistry::removeMapLayers ( QStringList theLayerIds )

Remove a set of layers from the registry.

Any canvases using the affected layers will need to remove them

The layers being removed are deleted as well as the registry table entries.

Parameters:

theLayerIds The ids of the layers to remove

Note:: As a side-effect QgsProject is made dirty.

Definition at line 121 of file qgsmaplayerregistry.cpp.

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

Referenced by QgsOfflineEditing::copyVectorLayer(), removeAllMapLayers(), removeMapLayer(), and QgsOfflineEditing::synchronize().

Member Data Documentation

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

Definition at line 220 of file qgsmaplayerregistry.h.

Referenced by instance().

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

Definition at line 222 of file qgsmaplayerregistry.h.

Referenced by addMapLayers(), clearAllLayerCaches(), count(), mapLayer(), mapLayers(), mapLayersByName(), reloadAllLayers(), removeAllMapLayers(), and removeMapLayers().

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

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

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