在 Pyside 中实现 QQuickAsyncImageProvider；没有这样的信号 QObject::finished()

Question

我正在尝试实现 QQuickAsyncImageProvider in Pyside6, referring to the official example. I'm already aware of the potential hurdle that, unlike in the C++ example code, with PySide it's not possible to inherit from both QRunnable and QObject. In order to send a signal from my QRunnable I'm instead using an intermediary QObject, as suggested here 的子类。那部分工作正常。

到目前为止，这是我尝试将这种安排与我自己的 QQuickAsyncImageProvider 子类一起使用：

from PySide6.QtGui import QGuiApplication, QImage
from PySide6.QtQml import QQmlApplicationEngine
from PySide6.QtCore import QObject, QRunnable, QThreadPool, Signal
from PySide6.QtQuick import (QQuickImageResponse, QQuickAsyncImageProvider,
                             QQuickTextureFactory)

class Signaller(QObject):
    done = Signal(QImage)


class AsyncImageResponseRunnable(QRunnable):
    def __init__(self):
        super().__init__()
        self.signaller = Signaller()
        self.done = self.signaller.done

    def run(self):
        image = QImage(400, 400, QImage.Format_RGB32)
        image.fill('red')
        self.done.emit(image)


class AsyncImageResponse(QQuickImageResponse):
    def __init__(self):
        super().__init__()

        runnable = AsyncImageResponseRunnable()
        runnable.done.connect(self.handle_done)
        pool = QThreadPool.globalInstance()
        pool.start(runnable)

    def handle_done(self, image):
        self.image = image
        self.finished.emit()
    
    def textureFactory(self):
        return QQuickTextureFactory.textureFactoryForImage(self.image)


class AsyncImageProvider(QQuickAsyncImageProvider):
    def requestImageResponse(self, image_id, requested_size):
        return AsyncImageResponse()


if __name__ == "__main__":
    app = QGuiApplication()
    engine = QQmlApplicationEngine()
    
    engine.addImageProvider('async_test', AsyncImageProvider())
    
    engine.load('test.qml')
    app.exec()

//test.qml

import QtQuick

Window {
    width: 1200
    height: 800
    visible: true

    Image {
        source: 'image://async_test/test'
    }
}

这会导致分段错误 - 有时，我会立即收到此错误消息：

qt.core.qobject.connect: QObject::connect: No such signal QObject::finished()

乍一看，这似乎与 self.finished.emit() 行有关。然而：

QQuickImageResponse定义了finished信号，
即使我注释掉 self.finished.emit()，我也收到相同的错误消息，这似乎表明内部必须尝试调用它。

那么，我在这里缺少什么？如何避免分段错误并使我的异步图像提供程序正常运行？

Answer 1

我 reported this 万一这是一个错误，其中一位维护人员意识到问题是 AsyncImageResponse 被立即删除了。解决方法是在 AsyncImageProvider:

中保留对它的引用

class AsyncImageProvider(QQuickAsyncImageProvider):
    def requestImageResponse(self, image_id, requested_size):
        self.response = AsyncImageResponse()
        return self.response

他们还提出了一个 change 可能会在将来不再需要这样做。

在 Pyside 中实现 QQuickAsyncImageProvider；没有这样的信号 QObject::finished()

Implementing QQuickAsyncImageProvider in Pyside; No such signal QObject::finished()

python

pyside

qtquick2