Base class for feedback objects to be used for cancellation of something running in a worker thread. More...
#include <qgsfeedback.h>
Signals | |
| void | cancelled () |
| Internal routines can connect to this signal if they use event loop. More... | |
Public Member Functions | |
| QgsFeedback (QObject *parent=nullptr) | |
| Construct a feedback object. More... | |
| virtual | ~QgsFeedback () |
| void | cancel () |
| Tells the internal routines that the current operation should be cancelled. This should be run by the main thread. More... | |
| bool | isCancelled () const |
| Tells whether the operation has been cancelled already. More... | |
 Public Member Functions inherited from QObject | |
| QObject (QObject *parent) | |
| QObject (QObject *parent, const char *name) | |
| virtual | ~QObject () |
| bool | blockSignals (bool block) |
| QObject * | child (const char *objName, const char *inheritsClass, bool recursiveSearch) const |
| const QObjectList & | children () const |
| const char * | className () const |
| bool | connect (const QObject *sender, const char *signal, const char *method, Qt::ConnectionType type) const |
| void | deleteLater () |
| void | destroyed (QObject *obj) |
| bool | disconnect (const QObject *receiver, const char *method) |
| bool | disconnect (const char *signal, const QObject *receiver, const char *method) |
| void | dumpObjectInfo () |
| void | dumpObjectTree () |
| QList< QByteArray > | dynamicPropertyNames () const |
| virtual bool | event (QEvent *e) |
| virtual bool | eventFilter (QObject *watched, QEvent *event) |
| T | findChild (const QString &name) const |
| QList< T > | findChildren (const QRegExp ®Exp) const |
| QList< T > | findChildren (const QString &name) const |
| bool | inherits (const char *className) const |
| void | insertChild (QObject *object) |
| void | installEventFilter (QObject *filterObj) |
| bool | isA (const char *className) const |
| bool | isWidgetType () const |
| void | killTimer (int id) |
| virtual const QMetaObject * | metaObject () const |
| void | moveToThread (QThread *targetThread) |
| const char * | name () const |
| const char * | name (const char *defaultName) const |
| QString | objectName () const |
| QObject * | parent () const |
| QVariant | property (const char *name) const |
| void | removeChild (QObject *object) |
| void | removeEventFilter (QObject *obj) |
| void | setName (const char *name) |
| void | setObjectName (const QString &name) |
| void | setParent (QObject *parent) |
| bool | setProperty (const char *name, const QVariant &value) |
| bool | signalsBlocked () const |
| int | startTimer (int interval) |
| QThread * | thread () const |
Additional Inherited Members | |
| Static Public Member Functions inherited from QObject | |
| bool | connect (const QObject *sender, const char *signal, const QObject *receiver, const char *method, Qt::ConnectionType type) |
| bool | connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type) |
| bool | disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *method) |
| bool | disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method) |
| QString | tr (const char *sourceText, const char *disambiguation, int n) |
| QString | trUtf8 (const char *sourceText, const char *disambiguation, int n) |
| Protected Member Functions inherited from QObject | |
| bool | checkConnectArgs (const char *signal, const QObject *object, const char *method) |
| virtual void | childEvent (QChildEvent *event) |
| virtual void | connectNotify (const char *signal) |
| virtual void | customEvent (QEvent *event) |
| virtual void | disconnectNotify (const char *signal) |
| int | receivers (const char *signal) const |
| QObject * | sender () const |
| int | senderSignalIndex () const |
| virtual void | timerEvent (QTimerEvent *event) |
| Static Protected Member Functions inherited from QObject | |
| QByteArray | normalizeSignalSlot (const char *signalSlot) |
| Properties inherited from QObject | |
| objectName | |
Detailed Description
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 cancelled() signal and handle the cancellation in its slot.
- if the worker thread does not use an event loop, it can poll isCancelled() method regularly to see if the operation should be cancelled.
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 with QgsMapLayerRenderer::feedback() method. When a map rendering job gets cancelled, the cancel() method is called on the feedback object of all layers.
- Note
- added in QGIS 2.18
Definition at line 40 of file qgsfeedback.h.
Constructor & Destructor Documentation
◆ QgsFeedback()
|
inline |
Construct a feedback object.
Definition at line 45 of file qgsfeedback.h.
◆ ~QgsFeedback()
|
inlinevirtual |
Definition at line 50 of file qgsfeedback.h.
Member Function Documentation
◆ cancel()
|
inline |
Tells the internal routines that the current operation should be cancelled. This should be run by the main thread.
Definition at line 53 of file qgsfeedback.h.
◆ cancelled
|
signal |
Internal routines can connect to this signal if they use event loop.
◆ isCancelled()
|
inline |
Tells whether the operation has been cancelled already.
Definition at line 62 of file qgsfeedback.h.
The documentation for this class was generated from the following file:
- /tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsfeedback.h
