QgsTask task which performs a QgsVectorLayerExporter layer export operation as a background task. More...

#include <qgsvectorlayerexporter.h>

Inheritance diagram for QgsVectorLayerExporterTask:

Signals
void	errorOccurred (Qgis::VectorExportResult error, const QString &errorMessage)
	Emitted when an error occurs which prevented the layer being exported (or if the task is canceled).

void	exportComplete ()
	Emitted when exporting the layer is successfully completed.

Signals inherited from QgsTask
void	begun ()
	Will be emitted by task to indicate its commencement.

void	progressChanged (double progress)
	Will be emitted by task when its progress changes.

void	statusChanged (int status)
	Will be emitted by task when its status changes.

void	taskCompleted ()
	Will be emitted by task to indicate its successful completion.

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).

Public Member Functions
	QgsVectorLayerExporterTask (QgsVectorLayer *layer, const QString &uri, const QString &providerKey, const QgsCoordinateReferenceSystem &destinationCrs, const QMap< QString, QVariant > &options=QMap< QString, QVariant >(), bool ownsLayer=false)
	Constructor for QgsVectorLayerExporterTask.

void	cancel () override
	Notifies the task that it should terminate.

Public Member Functions inherited from QgsTask
	QgsTask (const QString &description=QString(), QgsTask::Flags flags=AllFlags)
	Constructor for QgsTask.

	~QgsTask () override

void	addSubTask (QgsTask *subTask, const QgsTaskList &dependencies=QgsTaskList(), SubTaskDependency subTaskDependency=SubTaskIndependent)
	Adds a subtask to this task.

bool	canCancel () const
	Returns `true` if the task can be canceled.

QList< QgsMapLayer * >	dependentLayers () const
	Returns the list of layers on which the task depends.

QString	description () const
	Returns the task's description.

qint64	elapsedTime () const
	Returns the elapsed time since the task commenced, in milliseconds.

Flags	flags () const
	Returns the flags associated with the task.

void	hold ()
	Places the task on hold.

bool	isActive () const
	Returns `true` if the task is active, ie it is not complete and has not been canceled.

double	progress () const
	Returns the task's progress (between 0.0 and 100.0)

void	setDependentLayers (const QList< QgsMapLayer * > &dependentLayers)
	Sets a list of layers on which the task depends.

void	setDescription (const QString &description)
	Sets the task's description.

TaskStatus	status () const
	Returns the current task status.

void	unhold ()
	Releases the task from being held.

bool	waitForFinished (int timeout=30000)
	Blocks the current thread until the task finishes or a maximum of timeout milliseconds.

Static Public Member Functions
static QgsVectorLayerExporterTask *	withLayerOwnership (QgsVectorLayer *layer, const QString &uri, const QString &providerKey, const QgsCoordinateReferenceSystem &destinationCrs, const QMap< QString, QVariant > &options=QMap< QString, QVariant >())
	Creates a new QgsVectorLayerExporterTask which has ownership over a source layer.

Protected Member Functions
void	finished (bool result) override
	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).

bool	run () override
	Performs the task's operation.

Protected Member Functions inherited from QgsTask
bool	isCanceled () const
	Will return `true` if task should terminate ASAP.

Additional Inherited Members
Public Types inherited from QgsTask
enum	Flag { CanCancel = 1 << 1 , CancelWithoutPrompt = 1 << 2 , Hidden = 1 << 3 , Silent = 1 << 4 , 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.

Detailed Description

QgsTask task which performs a QgsVectorLayerExporter layer export operation as a background task.

This can be used to export a vector layer out to a provider without blocking the QGIS interface.

See also: QgsVectorFileWriterTask; QgsRasterFileWriterTask

Since: QGIS 3.0

Definition at line 180 of file qgsvectorlayerexporter.h.

Constructor & Destructor Documentation

◆ QgsVectorLayerExporterTask()

QgsVectorLayerExporterTask::QgsVectorLayerExporterTask	(	QgsVectorLayer *	layer,
		const QString &	uri,
		const QString &	providerKey,
		const QgsCoordinateReferenceSystem &	destinationCrs,
		const QMap< QString, QVariant > &	options = `QMap<QString, QVariant>()`,
		bool	ownsLayer = `false`
	)

Constructor for QgsVectorLayerExporterTask.

Takes a source layer, destination uri and providerKey, and various export related parameters such as destination CRS and export options. ownsLayer has to be set to true if the task should take ownership of the layer and delete it after export.

Definition at line 533 of file qgsvectorlayerexporter.cpp.

Member Function Documentation

◆ cancel()

void QgsVectorLayerExporterTask::cancel ( )

overridevirtual

Notifies the task that it should terminate.

Calling this is not guaranteed to immediately end the task, rather it sets the isCanceled() flag which task subclasses can check and terminate their operations at an appropriate time. Any subtasks owned by this task will also be canceled. Derived classes must ensure that the base class implementation is called from any overridden version.

See also: isCanceled()

Reimplemented from QgsTask.

Definition at line 554 of file qgsvectorlayerexporter.cpp.

◆ errorOccurred

void QgsVectorLayerExporterTask::errorOccurred	(	Qgis::VectorExportResult	error,
		const QString &	errorMessage
	)

signal

Emitted when an error occurs which prevented the layer being exported (or if the task is canceled).

The export error and errorMessage will be reported.

◆ exportComplete

void QgsVectorLayerExporterTask::exportComplete ( )

signal

Emitted when exporting the layer is successfully completed.

◆ finished()

void QgsVectorLayerExporterTask::finished ( bool result )

overrideprotectedvirtual

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.

Reimplemented from QgsTask.

Definition at line 575 of file qgsvectorlayerexporter.cpp.

◆ run()

bool QgsVectorLayerExporterTask::run ( )

overrideprotectedvirtual

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 560 of file qgsvectorlayerexporter.cpp.

◆ withLayerOwnership()

QgsVectorLayerExporterTask * QgsVectorLayerExporterTask::withLayerOwnership	(	QgsVectorLayer *	layer,
		const QString &	uri,
		const QString &	providerKey,
		const QgsCoordinateReferenceSystem &	destinationCrs,
		const QMap< QString, QVariant > &	options = `QMap<QString, QVariant>()`
	)

static

Creates a new QgsVectorLayerExporterTask which has ownership over a source layer.

When the export task has completed (successfully or otherwise) layer will be deleted. The destination uri and providerKey, and various export related parameters such as destination CRS and export options must be specified.

Definition at line 547 of file qgsvectorlayerexporter.cpp.

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

/build/qgis-3.34.0+99sid/src/core/vector/qgsvectorlayerexporter.h
/build/qgis-3.34.0+99sid/src/core/vector/qgsvectorlayerexporter.cpp

Signals

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members