- class QQuickImageResponse#
The
QQuickImageResponse
class provides an interface for asynchronous image loading inQQuickAsyncImageProvider
. More…Synopsis#
Methods#
def
__init__()
Virtual methods#
def
cancel()
def
errorString()
def
textureFactory()
Signals#
def
finished()
Note
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Detailed Description#
The purpose of an image response is to provide a way for image provider jobs to be executed in an asynchronous way.
Responses are deleted via deleteLater once the
finished()
signal has been emitted. If you are using QRunnable as base for yourQQuickImageResponse
ensure automatic deletion is disabled.See the Image Response Provider Example for a complete implementation.
See also
- __init__()#
Constructs the image response
- cancel()#
This method is used to communicate that the response is no longer required by the engine.
It may be reimplemented to cancel a request in the provider side, however, it is not mandatory.
A cancelled
QQuickImageResponse
still needs to emitfinished()
so that the engine may clean up theQQuickImageResponse
.Note
finished()
should not be emitted until the response is complete, regardless of whether or not cancel() was called. If it is called prematurely, the engine may destroy the response while it is still active, leading to a crash.- errorString()#
- Return type:
str
Returns the error string for the job execution. An empty string means no error.
- finished()#
Signals that the job execution has finished (be it successfully, because an error happened or because it was cancelled).
Note
Emission of this signal must be the final action the response performs: once the signal is received, the response will subsequently be destroyed by the engine.
- abstract textureFactory()#
- Return type:
Returns the texture factory for the job. You can use
textureFactoryForImage
if your provider works with QImage. The engine takes ownership of the returnedQQuickTextureFactory
.Note
This method will be called only when needed. For example, it may not be called if there is an error or the job is cancelled. Therefore, allocate the
QQuickTextureFactory
instance only in this method or otherwise ensure its deletion.