一起对 QObject 和 QThread 进行多类化

Question

我正在尝试创建一组状态机来处理我的 PyQt 项目中的不同任务，在处理图形需要在单个线程上处理的方式的过程中，我创建了两种类型的状态机，一个必须继承 QObject 的 StateMachine 和一个 ThreadedStateMachine，为了避免重复代码，我已经从 StateMachine 和 QThread 继承。

这是我复制问题的最少完整代码：

from PyQt5.QtCore import QObject, QThread


class StateMachine(QObject):
    def __init__(self):
        super().__init__()


class ThreadedStateMachine(StateMachine, QThread):
    def __init__(self):
        super().__init__()


if __name__ == "__main__":
    t = ThreadedStateMachine()

我希望它能正常工作，但我却收到了这个异常

QObject::connect: No such signal ThreadedStateMachine::started()
Traceback (most recent call last):
  File "/snap/pycharm-community/132/helpers/pydev/pydevd.py", line 1758, in <module>
    main()
  File "/snap/pycharm-community/132/helpers/pydev/pydevd.py", line 1752, in main
    globals = debugger.run(setup['file'], None, None, is_module)
  File "/snap/pycharm-community/132/helpers/pydev/pydevd.py", line 1147, in run
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File "/snap/pycharm-community/132/helpers/pydev/_pydev_imps/_pydev_execfile.py", line 18, in execfile
    exec(compile(contents+"\n", file, 'exec'), glob, loc)
  File "/home/aaron/.PyCharmCE2019.1/config/scratches/emerson_pmd/new/scratch_7.py", line 15, in <module>
    t = ThreadedStateMachine()
  File "/home/aaron/.PyCharmCE2019.1/config/scratches/emerson_pmd/new/scratch_7.py", line 11, in __init__
    super().__init__()
  File "/home/aaron/.PyCharmCE2019.1/config/scratches/emerson_pmd/new/scratch_7.py", line 6, in __init__
    super().__init__()
  File "/snap/pycharm-community/132/helpers/pydev/_pydev_bundle/pydev_monkey_qt.py", line 181, in __init__
    self.started = StartedSignalWrapper(self, self.started)
  File "/snap/pycharm-community/132/helpers/pydev/_pydev_bundle/pydev_monkey_qt.py", line 151, in __init__
    self.original_started.connect(self._signal)
TypeError: connect() failed between started() and _signal()

将 QObject 和 QThread 类组合成一个对象的正确方法是什么？

备注

我目前正在使用 threading.Thread 作为解决方法，但我希望能够从另一个线程启动 QMessageBox，它显示错误：

QObject::connect: Cannot queue arguments of type 'QItemSelection'
(Make sure 'QItemSelection' is registered using qRegisterMetaType().)
QBasicTimer::start: Timers cannot be started from another thread

我相信在这里使用 QThread 会奏效。

Answer 1

你遇到了一个问题 PyQt 不允许双重继承 2 个 QObject，StateMachine 是一个 QObject，QThread 也是一个 QObject（参见 docs）。

我不认为问题是由 threading.Thread() 引起的，我怀疑这是因为您正在修改某个线程中的对象而不是 thread-safe，QObjects不是 thread-safe 所以你必须在它们所在的线程中与这些对象交互，模型是 QObject。

阅读：

一起对 QObject 和 QThread 进行多类化

Multiclassing QObject and QThread together

python

pyqt

pyqt5

qthread

qobject

备注