Class: QgsFeedback¶
- class qgis.core.QgsFeedback¶
Bases:
PyQt5.QtCore.QObject
Base class for feedback objects to be used for cancellation of something running in a worker thread.
The class may be used as is or it may be subclassed for extended functionality for a particular operation (e.g. report progress or pass some data for preview).
When
cancel()
is called, the internal code has two options to check for cancellation state:if the worker thread uses an event loop (e.g. for network communication), the code can make a queued connection to
canceled()
signal and handle the cancellation in its slot.if the worker thread does not use an event loop, it can poll
isCanceled()
method regularly to see if the operation should be canceled.
The class is meant to be created and destroyed in the main thread.
For map rendering, the object may be created in constructor of a
QgsMapLayerRenderer
subclass and available withQgsMapLayerRenderer.feedback()
method. When a map rendering job gets canceled, thecancel()
method is called on the feedback object of all layers.New in version 3.0.
QgsFeedback(parent: QObject = None) Construct a feedback object
Methods
Tells the internal routines that the current operation should be canceled.
Tells whether the operation has been canceled already
Returns the current processed objects count reported by the feedback object.
Returns the current progress reported by the feedback object.
Sets the current processed objects count for the feedback object.
Sets the current progress for the feedback object.
Signals
Internal routines can connect to this signal if they use event loop [signal]
Emitted when the feedback object reports a progress change.
- cancel(self)¶
Tells the internal routines that the current operation should be canceled. This should be run by the main thread
- canceled¶
Internal routines can connect to this signal if they use event loop [signal]
- childEvent(self, QChildEvent)¶
- connectNotify(self, QMetaMethod)¶
- customEvent(self, QEvent)¶
- disconnectNotify(self, QMetaMethod)¶
- isCanceled(self) bool ¶
Tells whether the operation has been canceled already
- Return type
bool
- isSignalConnected(self, QMetaMethod) bool ¶
- processedCount(self) int ¶
Returns the current processed objects count reported by the feedback object. Depending on how the feedback object is used processed count reporting may not be supported. The returned value is an unsigned long integer and starts from 0.
See also
See also
processedCountChanged()
New in version 3.24.
- Return type
int
- progress(self) float ¶
Returns the current progress reported by the feedback object. Depending on how the feedback object is used progress reporting may not be supported. The returned value is in percentage and ranges from 0-100.
See also
See also
New in version 3.0.
- Return type
float
- progressChanged¶
Emitted when the feedback object reports a progress change. Depending on how the feedback object is used progress reporting may not be supported. The
progress
argument is in percentage and ranges from 0-100.See also
See also
New in version 3.0: [signal]
- Parameters
progress (float) –
- receivers(self, PYQT_SIGNAL) int ¶
- sender(self) QObject ¶
- senderSignalIndex(self) int ¶
- setProcessedCount(self, processedCount: int)¶
Sets the current processed objects count for the feedback object. The
processedCount
argument is an unsigned long integer and starts from 0.See also
See also
processedCountChanged()
New in version 3.24.
- Parameters
processedCount (int) –
- setProgress(self, progress: float)¶
Sets the current progress for the feedback object. The
progress
argument is in percentage and valid values range from 0-100.See also
See also
New in version 3.0.
- Parameters
progress (float) –
- timerEvent(self, QTimerEvent)¶