PyQt5 QObject:无法为处于不同线程中的父级创建子级 [英] PyQt5 QObject: Cannot create children for a parent that is in a different thread
问题描述
我正在使用PyQt5在菜单系统托盘中工作.我是PyQt5的新手，我想做的是在不阻止菜单(多线程)的情况下触发操作.在许多地方阅读完之后，我得出的结论是使用Qthread应该是可行的方法(但是，如果我能理解该类的工作原理……).但是，考虑到我的应用程序非常简单，threading的使用也不会很糟糕.因此，我尝试使用import threading尝试以下代码:
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Search时，该操作将触发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不会被阻塞，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，菜单仍然具有功能性"，因为它具有响应性，但无法触发更多操作.此外，似乎没有更多的线程被创建.如果有人可以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:
我现在创建了一个包含以下内容的worker.py
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()
然后我在class menubar中添加了以下内容:
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正在从我称为cc的外部类中恢复availablecc.但是由于某些原因，menubar类未收到该消息.我正在基于 https://stackoverflow.com/a/33453124/1995261
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，该worker.py执行阻塞菜单的方法_search_cast_.此方法完成搜索后，将发出两个信号:a)一个通知他已恢复list的信号，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中，我转储了以下内容，并尝试在代码中解释带注释的内容:
#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时菜单不会被阻塞，屏幕上不会显示任何错误，并且在activity monitor中监视它们时threads的数量保持正确.
我希望这对人们有帮助.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.
I am working in a menu system tray with PyQt5. I am very new with PyQt5, and what I want to do is to trigger an action without the menu being blocked (multithreading). After having read in many places, I have come to the conclusion that using Qthread should be the way to go (but if only I could understand how that class works...). However, the use of threading wouldn't be that bad either given that my application is very simple. So, I have tried the following code using 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()
When I start my menu, everything is in place as I expect it. Then, when I click on the menu Search the action triggers the self.search_cast method, and my menu gets populated with the list it finds. I can also see my application doing the searching without getting blocked but when it finishes I get the following errors:
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.
After this, the menu is still "functional" in the sense that it is responsive but no more action can be triggered. Additionally, it seems that no more threads are created. I would be glad if somebody could explain me why is this happening?. I don't see the light...
Update:
I have created now a worker.py that contains:
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()
Then I have added in the class menubar the following:
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.
And now I get the following error:
AttributeError: 'casting' object has no attribute 'availablecc'
I make sure that actually the worker is recovering availablecc from an external class that I called cc. But for some reason is not being received by the menubar class. I am working based on this https://stackoverflow.com/a/33453124/1995261
I will proceed to answer myself. Inspired by https://stackoverflow.com/a/33453124/1995261, I solved this by implementing the following:
1) I created a worker.py that executes the method _search_cast_ that was blocking the menu. When this method finishes searching, it emits two signals: a) one informing that he recovered the list, and b) that the method has finished.
#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) In the main.py I dumped the following and I try to explain inside the code with comments:
#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()
In this way, when searching for the list the menu does not get blocked, no errors are shown on the screen and the number of threads when monitoring them in activity monitor stay correct.
I hope this helps people. For more precise information (I am still learning PyQt and my wording may not be very good), I suggest you to check the link that I posted above.
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