PyQt5 QObject：无法为处于不同线程中的父级创建子级

Question

我正在使用PyQt5在菜单系统托盘中工作。我对PyQt5非常陌生，我想做的是在不阻止菜单（多线程）的情况下触发操作。在许多地方看完书后，我得出的结论是使用Qthread应该是可行的方式（但前提是我能理解该类的工作原理……）。但是，threading鉴于我的应用程序非常简单，使用of也不会很糟糕。因此，我尝试使用以下代码import threading：

from PyQt5 import QtCore, QtGui, QtWidgets
import threading

class menubar(object):
    def __init__(self):
    signal.signal(signal.SIGINT, signal.SIG_DFL)
    self.systray = True
    self.stopped = False

    def search_menu(self):
        self.SearchAction = menu.addAction("Search")
        self.SearchAction.triggered.connect(self.search_cast)

    def _search_cast_(self):
        args.select_cc = True
        self.cc.initialize_cast()
        self.cast_list()

    def search_cast(self):
        threading.Thread(target=self._search_cast_).start()

#some more methods here...

def main():

    menubar()
    app = QtWidgets.QApplication(sys.argv)
    tray = QtWidgets.QSystemTrayIcon(icon)

    menu = QtWidgets.QMenu()
    start = menubar()
    start.search_menu()
    start.separator_menu()
    start.populating_menu()
    start.separator_menu()
    start.stop_menu()
    start.resetaudio_menu()
    start.about_menu()
    start.exit_menu()

    tray.setContextMenu(menu)
    tray.show()
    app.exec_()

if __name__ == '__main__':
     main()

当我开始菜单时，一切都已准备就绪。然后，当我单击菜单时，Search该操作将触发该self.search_cast方法，并且菜单中将包含找到的列表。我还可以看到我的应用程序在进行搜索时没有被阻塞，但是完成时会出现以下错误：

QObject: Cannot create children for a parent that is in a different thread.
(Parent is QMenu(0x7fcef497c160), parent's thread is     QThread(0x7fcef2603d10), current thread is QThread(0x7fcef4a89360)
QObject: Cannot create children for a parent that is in a different thread.
(Parent is QMenu(0x7fcef497c160), parent's thread is  QThread(0x7fcef2603d10), current thread is QThread(0x7fcef4a89360)
QObject: Cannot create children for a parent that is in a different thread.

此后，菜单仍然具有响应性，但无法触发更多操作，因此它仍是“功能性”的。此外，似乎没有更多的线程被创建。如果有人能解释我为什么会发生这种情况，我将感到非常高兴。我看不到光…

更新 ：

我现在创建了一个worker.py包含以下内容的：

from PyQt5.QtCore import QThread, QObject, pyqtSignal, pyqtSlot
#some other imports


class Worker(QObject):
    finished = pyqtSignal()


@pyqtSlot()
def _search_cast_(self):
    self.cc = casting()
    self.cc.initialize_cast()
    self.finished.emit()

然后我添加class menubar了以下内容：

class menubar(object):
    def __init__(self):
        self.cc = casting()
        signal.signal(signal.SIGINT, signal.SIG_DFL)
        self.cc.cast = None
        self.systray = True
        self.stopped = False

        self.obj = worker.Worker()  # no parent!
        self.thread = QThread()  # no parent!
        self.obj.moveToThread(self.thread)
        self.obj.finished.connect(self.thread.quit)
        self.thread.started.connect(self.obj._search_cast_)

  def search_menu(self):
        self.SearchAction = menu.addAction("Search")
        self.SearchAction.triggered.connect(self.search_cast)

  def search_cast(self):
    self.thread.start()
    self.cast_list()

  def cast_list(self):
     if len(self.cc.availablecc) == 0:
     # some actions here.

现在我得到以下错误：

 AttributeError: 'casting' object has no attribute 'availablecc'

我确保实际上worker是availablecc从我调用的外部类中恢复的cc。但是由于某种原因，menubar班级没有收到
。我正在基于此https://stackoverflow.com/a/33453124/1995261

Answer 1

我将继续回答自己。受https://stackoverflow.com/a/33453124/1995261的启发，我通过实现以下方法解决了这一问题：

1）我创建了一个worker.py执行_search_cast_阻止菜单的方法的。当此方法完成搜索时，它会发出两个信号：a）一个通知他恢复了该信号list，以及b）该方法已完成。

#worker.py
from PyQt5.QtCore import QThread, QObject, pyqtSignal, pyqtSlot


class Worker(QObject):
    finished = pyqtSignal()
    intReady = pyqtSignal(list)
    def __init__(self):
        QObject.__init__(self)

    @pyqtSlot()
    def _search_cast_(self):
        self.cc = casting()
        self.cc.initialize_cast()
        availablecc = self.cc.availablecc
        self.intReady.emit(availablecc)
        self.finished.emit()

2）在“main.py我转储了以下内容”并尝试在代码内用注释进行解释：

#main.py
from PyQt5.QtCore import QThread, QObject, pyqtSignal, pyqtSlot
import worker # This is to import worker.py
class menubar(object):
    def __init__(self):
        signal.signal(signal.SIGINT, signal.SIG_DFL)
        self.cc.cast = None
        self.systray = True
        self.stopped = False

        self.obj = worker.Worker()  # The worker is started with no parent!
        self.thread = QThread()  # We initialise the Qthread class with no parent!
        self.obj.intReady.connect(self.onIntReady) # We receive the signal that the list is ready
        self.obj.moveToThread(self.thread) # Moving the object to the thread
        self.obj.finished.connect(self.thread.quit) # When the method is finished we receive the signal that it is finished
        self.thread.started.connect(self.obj._search_cast_) # We need to connect the above with the desired method inside the work.py

        self.app = QtWidgets.QApplication(sys.argv)

        def search_menu(self):
            self.SearchAction = self.menu.addAction("Search")
            self.SearchAction.triggered.connect(self.search_cast)

        def onIntReady(self, availablecc):     # This method receives the list from the worker
            print ('availablecc', availablecc)  # This is for debugging reasons to verify that I receive the list with the correct content
            self.availablecc = availablecc

        def search_cast(self):   #This method starts the thread when  self.SearchAction is triggered
            args.select_cc = True
            self.thread.start()

这样，在搜索list菜单时不会被阻塞，屏幕上不会显示任何错误，并且threads监控它们的次数activity monitor保持正确。

希望对大家有帮助。有关更精确的信息（我仍在学习PyQt，并且措辞可能不太好），建议您检查上面发布的链接。