QThread 的 started() 信号没有发出

Question

我发现我的应用 QThread.start() 不像 documentation claims 那样发出 started() 信号。我已将 started() 信号连接到插槽，但除非我明确调用 started.emit().

否则它永远不会触发

我已将我的代码缩减为可运行的问题演示。如您所见，信号实际上连接到插槽，线程实际上由 start() 启动，所以这些都不是问题。

started() 从未发出有什么问题？

#!/usr/bin/env python3

import PySide2.QtCore
import PySide2.QtWidgets


@PySide2.QtCore.Slot()
def test_receiver():
    print('thread.started() signal received.')


if __name__ == '__main__':
    app = PySide2.QtWidgets.QApplication()
    app.processEvents()

    thread = PySide2.QtCore.QThread()
    thread.started.connect(test_receiver)

    thread.start()

    # The connection between signal and slot isn't the problem because
    # the signal has actually connected, as evidenced if you uncomment the following line:
    # 
    # thread.started.emit()
    # 
    # So why is thread.started() never emitted after thread.start()?


    while thread.isRunning():
        print('Thread is running...')
        PySide2.QtCore.QThread.sleep(1)

    print('Everything quit.')

Answer 1

您的 while 循环阻塞了事件循环。 started 信号从另一个线程发出。在这种情况下，将使用排队连接，这意味着主线程需要去检查事件队列来处理插槽调用，但你的 while 循环正在阻止它。

QThread 的 started() 信号没有发出

QThread's started() signal is not emitted

qt

qthread

pyside2