您了解这种僵局吗? [英] Do you understand this deadlock?

问题描述

我将wxPython用于我的GUI.在AppLogic类中，我有一个工作线程，该线程在该类的方法中运行.

I'm using wxPython for my GUI. In the AppLogic class I have a worker thread that is run in a method of this very class.

这是GUI类:

class GUI:
    _wx_app = None
    _main_window = None
    _app_logic = None

    def start(self):
        # bla bla bla
        self._main_window.Show()
        self._app_logic.begin()
        self._wx_app.MainLoop()

    def _cancel_listener(self):
        """Called from MainWindow, if the user has clicked the cancel
        button."""
        print("I'm leaving this scope.")
        self._app_logic.cancel()  # Should cancel the task done in
                                  # a second thread.

    def _status_listener(self, status_text):
        """Called often by the worker thread."""
        print("Here I am again.")
        if self._main_window.status.GetLabel() != status_text:
            self._main_window.status.SetLabel(status_text)

这是AppLogic类中的cancel方法，由_cancel_listener从上面调用:

Here's the cancel method from the AppLogic class which is called by _cancel_listener from above:

    def cancel(self):
        self._shall_abort = True
        self._thread.join(self._some_time_out)
        assert self._thread.isAlive() == False

不知何故，其中涉及到join和GetLabel(因此也包括MainLoop?)陷入了僵局，但我并不真正了解发生了什么.有人对此有更深入的了解吗?那就太好了！

Somehow, there's a deadlock with join and GetLabel (and thus MainLoop?) involved, but I don't really understand what's going on. Does someone have more insight into this? That would be great!

推荐答案

所有GUI工具包都有一个主GUI线程.它们都有特殊的方法，可让您以线程安全的方式操作GUI小部件.在wxPython世界中，这些方法是wx.CallAfter，wx.CallLater和wx.PostEvent.我在您的示例中没有看到这些内容，因此您所做的基本上是暂停GUI线程或导致发生未定义"事件.

All GUI toolkits have a main GUI thread. They all have special methods that allow you to manipulate the GUI widgets in a thread-safe way. In wxPython world, those methods are wx.CallAfter, wx.CallLater and wx.PostEvent. I don't see those anywhere in your example, so what you're doing is basically pausing the GUI thread or causing something "undefined" to occur.

以下是有关线程和wxPython的几篇文章:

Here are a couple of articles on threads and wxPython:

• http://wiki.wxpython.org/LongRunningTasks
• http://www.blog.pythonlibrary.org /2010/05/22/wxpython-and-threads/

• http://wiki.wxpython.org/LongRunningTasks
• http://www.blog.pythonlibrary.org/2010/05/22/wxpython-and-threads/

这篇关于您了解这种僵局吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！