python - 中途结束程序

Question

pythoncom.PumpMessages()

据我了解，这条线基本上告诉程序永远等待。就我的目的而言，它似乎正在工作。但是，我希望能够在适当的刺激下结束该计划。如何结束上述行，或停止程序继续运行。

Answer 1

根据这些文档，pythoncom.PumpMessages()：

泵送当前线程的所有消息，直到出现 WM_QUIT 消息。

因此，停止收集消息的一种方法是通过使用ctypes库调用PostQuitMessage将 WM_QUIT 消息发布到消息队列：

ctypes.windll.user32.PostQuitMessage(0)

Answer 2

这是一个使用计时器线程退出应用程序的示例：

import win32api
import win32con
import pythoncom
from threading import Timer

main_thread_id = win32api.GetCurrentThreadId()

def on_timer():
    win32api.PostThreadMessage(main_thread_id, win32con.WM_QUIT, 0, 0);

t = Timer(5.0, on_timer) # Quit after 5 seconds
t.start()

pythoncom.PumpMessages()

PostQuitMessage()只能从主线程工作，但是主线程又被阻塞了，所以它本身并不是很有用。如果您将自己的自定义消息处理挂接到消息循环中，则只能使用它。

Answer 3

我想扩展Gregg和Boaz Yaniv的两个答案。您通常会在单独的线程中运行阻塞代码，因此您需要将 WM_QUIT 发送到线程。您应该使用Gregg 所指出的PostQuitMessage，但这仅适用于当前线程。您不应该使用PostThreadMessage发送 WM_QUIT （不记得我在文档中看到它的位置）。您可以在讨论“为什么有一个特殊的 PostQuitMessage 函数？ ”中阅读更多相关信息。我认为最好先将 WM_CLOSE 发送到线程。

# if more hotkeys needs to be supported at the same time this class needs to be rewritten
class HotKey:
    def __init__(self, modifier_key, virtual_key, callback):
        self.hotkey_id = 1
        # shared variable to pass thread id
        self.pid = mpdummy.Value('l', 0)

        # start checking hotkey press in new thread
        self.process_pool = mpdummy.Pool()
        self.process_pool.apply_async(HotKey.register, (self.hotkey_id, self.pid, modifier_key, virtual_key, callback, ))
        self.process_pool.close()

    # bind windows global hotkey
    @staticmethod
    def register(hotkey_id, pid, modifier_key, virtual_key, callback):
        # set thread ID to shared variable
        # Win API could also be used:
        # ctypes.windll.Kernel32.GetCurrentThreadId()
        pid.value = mpdummy.current_process().ident

        # register hotkey with Win API
        logging.getLogger('default').info("Registering hotkey with id " + str(hotkey_id) + " for key " + str(modifier_key) + " " + str(virtual_key))
        if not ctypes.windll.user32.RegisterHotKey(None, hotkey_id, modifier_key, virtual_key):
            logging.getLogger('default').info("Unable to register hotkey with id " + str(hotkey_id))

        msg = ctypes.wintypes.MSG()
        try:
            # wait for a message - it doesn't return until some message arrives
            while ctypes.windll.user32.GetMessageA(ctypes.byref(msg), None, 0, 0) != 0:
                # WM_HOTKEY     0x0312
                # https://msdn.microsoft.com/en-us/library/windows/desktop/ms646279(v=vs.85).aspx
                if msg.message == 0x0312:
                    logging.getLogger('default').info("Pressed hotkey with id " + str(hotkey_id))
                    callback()
                # WM_CLOSE
                # https://msdn.microsoft.com/en-us/library/windows/desktop/ms632617(v=vs.85).aspx
                elif msg.message == 0x0010:
                    # quit current thread
                    # WM_QUIT shouldn't be send with PostThreadMessageA therefore we send WM_CLOSE and quit inside thread.
                    # More info at:
                    # https://msdn.microsoft.com/en-us/library/windows/desktop/ms644945(v=vs.85).aspx
                    # https://blogs.msdn.microsoft.com/oldnewthing/20051104-33/?p=33453
                    ctypes.windll.user32.PostQuitMessage(0)
                ctypes.windll.user32.TranslateMessage(ctypes.byref(msg))
                ctypes.windll.user32.DispatchMessageA(ctypes.byref(msg))
        finally:
            logging.getLogger('default').info("Unregistering hotkey for id " + str(hotkey_id))
            ctypes.windll.user32.UnregisterHotKey(None, hotkey_id)

    def unregister(self):
        # send WM_CLOSE signal to thread checking for messages
        # WM_CLOSE      0x0010
        # https://msdn.microsoft.com/en-us/library/windows/desktop/ms632617(v=vs.85).aspx
        ctypes.windll.user32.PostThreadMessageA(self.pid.value, 0x0010, 0, 0)
        # wait for thread to finish
        self.process_pool.join()

我将它用于RegisterHotKey，但原理相同。这个类可以称为：

# bind global hotkey for "pressing" start/split button
# MOD_ALT       0x0001
# VK_F12        0x7B
# https://msdn.microsoft.com/en-us/library/windows/desktop/ms646309(v=vs.85).aspx
# https://msdn.microsoft.com/en-us/library/windows/desktop/dd375731.aspx
self.hotkey = hotkey.HotKey(0x0001, 0x7B, self.special_key_pressed)

当您想结束等待消息时：

self.hotkey.unregister()