QGIS API Documentation
3.0.2-Girona (307d082)
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Counts the features in a QgsVectorLayer in task. More...
#include <qgsvectorlayerfeaturecounter.h>
Signals | |
void | symbolsCounted () |
Emitted when the symbols have been counted. More... | |
Signals inherited from QgsTask | |
void | begun () |
Will be emitted by task to indicate its commencement. More... | |
void | progressChanged (double progress) |
Will be emitted by task when its progress changes. More... | |
void | statusChanged (int status) |
Will be emitted by task when its status changes. More... | |
void | taskCompleted () |
Will be emitted by task to indicate its successful completion. More... | |
void | taskTerminated () |
Will be emitted by task if it has terminated for any reason other then completion (e.g., when a task has been canceled or encountered an internal error). More... | |
Public Member Functions | |
QgsVectorLayerFeatureCounter (QgsVectorLayer *layer, const QgsExpressionContext &context=QgsExpressionContext()) | |
Create a new feature counter for layer. More... | |
long | featureCount (const QString &legendKey) const |
Get the feature count for a particular legendKey. More... | |
bool | run () override |
Performs the task's operation. More... | |
QHash< QString, long > | symbolFeatureCountMap () const |
Get the count for each symbol. More... | |
Public Member Functions inherited from QgsTask | |
QgsTask (const QString &description=QString(), QgsTask::Flags flags=AllFlags) | |
Constructor for QgsTask. More... | |
~QgsTask () override | |
void | addSubTask (QgsTask *subTask, const QgsTaskList &dependencies=QgsTaskList(), SubTaskDependency subTaskDependency=SubTaskIndependent) |
Adds a subtask to this task. More... | |
bool | canCancel () const |
Returns true if the task can be canceled. More... | |
virtual void | cancel () |
Notifies the task that it should terminate. More... | |
QList< QgsMapLayer *> | dependentLayers () const |
Returns the list of layers on which the task depends. More... | |
QString | description () const |
Returns the task's description. More... | |
Flags | flags () const |
Returns the flags associated with the task. More... | |
void | hold () |
Places the task on hold. More... | |
bool | isActive () const |
Returns true if the task is active, ie it is not complete and has not been canceled. More... | |
double | progress () const |
Returns the task's progress (between 0.0 and 100.0) More... | |
void | setDependentLayers (const QList< QgsMapLayer *> &dependentLayers) |
Sets a list of layers on which the task depends. More... | |
TaskStatus | status () const |
Returns the current task status. More... | |
void | unhold () |
Releases the task from being held. More... | |
bool | waitForFinished (unsigned long timeout=30000) |
Blocks the current thread until the task finishes or a maximum of timeout milliseconds. More... | |
Additional Inherited Members | |
Public Types inherited from QgsTask | |
enum | Flag { CanCancel = 1 << 1, AllFlags = CanCancel } |
Task flags. More... | |
enum | SubTaskDependency { SubTaskIndependent = 0, ParentDependsOnSubTask } |
Controls how subtasks relate to their parent task. More... | |
enum | TaskStatus { Queued, OnHold, Running, Complete, Terminated } |
Status of tasks. More... | |
Protected Slots inherited from QgsTask | |
void | setProgress (double progress) |
Sets the task's current progress. More... | |
Protected Member Functions inherited from QgsTask | |
virtual void | finished (bool result) |
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). More... | |
bool | isCanceled () const |
Will return true if task should terminate ASAP. More... | |
Counts the features in a QgsVectorLayer in task.
You should most likely not use this directly and instead call QgsVectorLayer::countSymbolFeatures() and connect to the signal QgsVectorLayer::symbolFeatureCountMapChanged().
Definition at line 33 of file qgsvectorlayerfeaturecounter.h.
QgsVectorLayerFeatureCounter::QgsVectorLayerFeatureCounter | ( | QgsVectorLayer * | layer, |
const QgsExpressionContext & | context = QgsExpressionContext() |
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Create a new feature counter for layer.
Definition at line 17 of file qgsvectorlayerfeaturecounter.cpp.
long QgsVectorLayerFeatureCounter::featureCount | ( | const QString & | legendKey | ) | const |
Get the feature count for a particular legendKey.
If the key has not been found, -1 will be returned.
Definition at line 100 of file qgsvectorlayerfeaturecounter.cpp.
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overridevirtual |
Performs the task's operation.
This method will be called when the task commences (ie via calling start() ), and subclasses should implement the operation they wish to perform in the background within this method.
A task must return a boolean value to indicate whether the task was completed successfully or terminated before completion.
Implements QgsTask.
Definition at line 30 of file qgsvectorlayerfeaturecounter.cpp.
QHash< QString, long > QgsVectorLayerFeatureCounter::symbolFeatureCountMap | ( | ) | const |
Get the count for each symbol.
Only valid after the symbolsCounted() signal has been emitted.
Definition at line 95 of file qgsvectorlayerfeaturecounter.cpp.
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signal |
Emitted when the symbols have been counted.