Class: QgsVectorLayerFeatureCounter¶
- class qgis.core.QgsVectorLayerFeatureCounter¶
Bases:
QgsTask
Counts the features in a
QgsVectorLayer
in task. You should most likely not use this directly and instead callQgsVectorLayer.countSymbolFeatures()
and connect to the signalQgsVectorLayer.symbolFeatureCountMapChanged()
.New in version 3.0.
QgsVectorLayerFeatureCounter(layer:
QgsVectorLayer
, context:QgsExpressionContext
= QgsExpressionContext(), storeSymbolFids: bool = False) Create a new feature counter forlayer
.- Parameters:
layer – Target
QgsVectorLayer
to perform counting on.context – Specific
QgsExpressionContext
to use during the rendering step.storeSymbolFids –
If
True
will store the feature ids (fids), otherwise will only count the number of features per symbol. DefaultFalse
.Methods
Returns the feature count for a particular
legendKey
.Returns the feature Ids for a particular
legendKey
.If the task is managed by a
QgsTaskManager
, this will be called after the task has finished (whether through successful completion or via early termination).Will return
True
if task should terminate ASAP.Calculates the feature count and Ids per symbol
Sets the task's current progress.
Signals
pyqtSignal(*types, name: str = ..., revision: int = ..., arguments: Sequence = ...) -> PYQT_SIGNAL
- cancel(self)¶
- childEvent(self, QChildEvent)¶
- connectNotify(self, QMetaMethod)¶
- customEvent(self, QEvent)¶
- disconnectNotify(self, QMetaMethod)¶
- featureCount(self, legendKey: str) int ¶
Returns the feature count for a particular
legendKey
. If the key has not been found, -1 will be returned.- Parameters:
legendKey (str) –
- Return type:
int
- featureIds(self, symbolkey: str) object ¶
Returns the feature Ids for a particular
legendKey
. If the key has not been found an empty QSet will be returned.New in version 3.10.
- Parameters:
symbolkey (str) –
- Return type:
object
- finished(self, result: bool)¶
If the task is managed by a
QgsTaskManager
, this will be called after the task has finished (whether through successful completion or via early termination). The result argument reflects whether the task was successfully completed or not. This method is always called from the main thread, so it is safe to create widgets and perform other operations which require the main thread. However, the GUI will be blocked for the duration of this method so tasks should avoid performing any lengthy operations here.
- isCanceled(self) bool ¶
Will return
True
if task should terminate ASAP. If the task reports the CanCancel flag, then derived classes’run()
methods should periodically check this and terminate in a safe manner.
- isSignalConnected(self, QMetaMethod) bool ¶
- receivers(self, PYQT_SIGNAL) int ¶
- run(self) bool ¶
Calculates the feature count and Ids per symbol
- Return type:
bool
- sender(self) QObject ¶
- senderSignalIndex(self) int ¶
- setProgress(self, progress: float)¶
Sets the task’s current progress. The derived class should call this method whenever the task wants to update its progress. Calling will automatically emit the progressChanged signal.
- Parameters:
progress – percent of progress, from 0.0 - 100.0
- symbolsCounted¶
pyqtSignal(*types, name: str = …, revision: int = …, arguments: Sequence = …) -> PYQT_SIGNAL
types is normally a sequence of individual types. Each type is either a type object or a string that is the name of a C++ type. Alternatively each type could itself be a sequence of types each describing a different overloaded signal. name is the optional C++ name of the signal. If it is not specified then the name of the class attribute that is bound to the signal is used. revision is the optional revision of the signal that is exported to QML. If it is not specified then 0 is used. arguments is the optional sequence of the names of the signal’s arguments.
- Parameters:
name (str = ...) –
revision (int = ...) –
arguments (Sequence = ...) –
- Return type:
PYQT_SIGNAL
- timerEvent(self, QTimerEvent)¶