Subgroup: Task

Class: QgsTaskManager¶

class qgis.core.QgsTaskManager¶

Bases: PyQt5.QtCore.QObject

Task manager for managing a set of long-running QgsTask tasks. This class can be created directly, or accessed via QgsApplication.taskManager()

New in version 3.0: Methods

`activeTasks`	Returns a list of the active (queued or running) tasks.
`addTask`	Adds a task to the manager.
`blockSignals`
`cancelAll`	Instructs all tasks tracked by the manager to terminate.
`childEvent`
`children`
`connectNotify`
`count`	Returns the number of tasks tracked by the manager.
`countActiveTasks`	Returns the number of active (queued or running) tasks.
`customEvent`
`deleteLater`
`dependenciesSatisfied`	Returns true if all dependencies for the specified task are satisfied
`dependentLayers`	Returns a list of layers on which as task is dependent.
`disconnect`
`disconnectNotify`
`dumpObjectInfo`
`dumpObjectTree`
`dynamicPropertyNames`
`event`
`eventFilter`
`findChild`	findChild(self, Tuple, name: str = ‘’, options: Union[Qt.FindChildOptions, Qt.FindChildOption] = Qt.FindChildrenRecursively) -> QObject
`findChildren`	findChildren(self, Tuple, name: str = ‘’, options: Union[Qt.FindChildOptions, Qt.FindChildOption] = Qt.FindChildrenRecursively) -> List[QObject]
`inherits`
`installEventFilter`
`isSignalConnected`
`isWidgetType`
`isWindowType`
`killTimer`
`metaObject`
`moveToThread`
`objectName`
`parent`
`property`
`pyqtConfigure`	Each keyword argument is either the name of a Qt property or a Qt signal.
`receivers`
`removeEventFilter`
`sender`
`senderSignalIndex`
`setObjectName`
`setParent`
`setProperty`
`signalsBlocked`
`startTimer`
`task`	Returns the task with matching ID.
`taskId`	Returns the unique task ID corresponding to a task managed by the class.
`tasks`	Returns all tasks tracked by the manager.
`tasksDependentOnLayer`	Returns a list of tasks which depend on a layer.
`thread`
`timerEvent`
`tr`

Attributes

`allTasksFinished`	Emitted when all tasks are complete
`countActiveTasksChanged`	Emitted when the number of active tasks changes
`destroyed`	destroyed(self, QObject = None) [signal]
`finalTaskProgressChanged`	Will be emitted when only a single task remains to complete
`objectNameChanged`	objectNameChanged(self, str) [signal]
`progressChanged`	Will be emitted when a task reports a progress change
`staticMetaObject`
`statusChanged`	Will be emitted when a task reports a status change
`taskAboutToBeDeleted`	Emitted when a task is about to be deleted
`taskAdded`	Emitted when a new task has been added to the manager

class TaskDefinition(task: QgsTask, dependentTasks: object = QgsTaskList())¶

Bases: sip.wrapper

Constructor for TaskDefinition. Ownership of the task is not transferred to the definition, but will be transferred to a QgsTaskManager.

QgsTaskManager.TaskDefinition(QgsTaskManager.TaskDefinition)

dependentTasks¶

task¶

activeTasks(self) → List[QgsTask]¶: Returns a list of the active (queued or running) tasks.

See also

countActiveTasks()

addTask(self, task: QgsTask, priority: int = 0) → int¶

Adds a task to the manager. Ownership of the task is transferred to the manager, and the task manager will be responsible for starting the task. The priority argument can be used to control the run queue’s order of execution, with larger numbers taking precedence over lower priority numbers.

Returns:	unique task ID

addTask(self, task: QgsTaskManager.TaskDefinition, priority: int = 0) -> int Adds a task to the manager, using a full task definition (including dependency handling). Ownership of the task is transferred to the manager, and the task manager will be responsible for starting the task. The priority argument can be used to control the run queue’s order of execution, with larger numbers taking precedence over lower priority numbers.

Returns:	unique task ID

allTasksFinished¶: Emitted when all tasks are complete

See also

countActiveTasksChanged() [signal]

cancelAll(self)¶: Instructs all tasks tracked by the manager to terminate. Individual tasks may take some time to cancel, or may totally ignore this instruction. Calling this does not block but will instead signal the tasks to cancel and then return immediately.

childEvent()¶

connectNotify()¶

count(self) → int¶: Returns the number of tasks tracked by the manager.

countActiveTasks(self) → int¶: Returns the number of active (queued or running) tasks.

See also

activeTasks()

See also

countActiveTasksChanged()

countActiveTasksChanged¶: Emitted when the number of active tasks changes

See also

countActiveTasks() [signal]

customEvent()¶

dependenciesSatisfied(self, taskId: int) → bool¶: Returns true if all dependencies for the specified task are satisfied

dependentLayers(self, taskId: int) → List[QgsMapLayer]¶

Returns a list of layers on which as task is dependent. The task will automatically be canceled if any of these layers are above to be removed.

Parameters:	taskId – task ID
Returns:	list of layers

See also

tasksDependentOnLayer()

disconnectNotify()¶

finalTaskProgressChanged¶

Will be emitted when only a single task remains to complete and that task has reported a progress change

Parameters:	progress – percent of progress, from 0.0 - 100.0 [signal]

isSignalConnected()¶

progressChanged¶

Will be emitted when a task reports a progress change

Parameters:	taskId – ID of task progress – percent of progress, from 0.0 - 100.0 [signal]

receivers()¶

sender()¶

senderSignalIndex()¶

statusChanged¶

Will be emitted when a task reports a status change

Parameters:	taskId – ID of task status – new task status [signal]

task(self, id: int) → QgsTask¶

Returns the task with matching ID.

Parameters:	id – task ID
Returns:	task if found, or None

taskAboutToBeDeleted¶

Emitted when a task is about to be deleted

Parameters:	taskId – ID of task [signal]

taskAdded¶

Emitted when a new task has been added to the manager

Parameters:	taskId – ID of task [signal]

taskId(self, task: QgsTask) → int¶

Returns the unique task ID corresponding to a task managed by the class.

Parameters:	task – task to find
Returns:	task ID, or -1 if task not found

tasks(self) → List[QgsTask]¶: Returns all tasks tracked by the manager.

tasksDependentOnLayer(self, layer: QgsMapLayer) → List[QgsTask]¶: Returns a list of tasks which depend on a layer.

See also

dependentLayers()

timerEvent()¶