PySide中没有处理的信号

Question

我有一个PySide应用程序。在这个应用程序中，主函数运行在一个线程中（AnalysisThread）。在这个线程中，我用Python记录器记录了一些东西。然后我添加一个自定义记录器，它实际上是用一个字符串触发一个信号。这个信号可以在主线程（GUI线程）中处理，但显然插槽永远不会触发，但我确信信号self.messageWritten.emit函数被调用（调试器确认这一点）。我究竟做错了什么 ？

class LogStream(QtCore.QObject): 
    messageWritten = QtCore.Signal(str) 
    signal_test = QtCore.Signal() 

    def write(self, msg): 
     if not self.signalsBlocked(): 
      self.messageWritten.emit(msg) 


class QtHandler(logging.Handler): 
    def __init__(self, stream): 
     logging.Handler.__init__(self) 
     self.stream = stream 

    def emit(self, record): 
     record = self.format(record) 
     if record: 
      self.stream.write('%s\n' % record) 

class AnalysisThread(QtCore.QThread): 
    processing_ended = QtCore.Signal() 
    processing_failed = QtCore.Signal(Exception, list) 

    def __init__(self, analysis): 
     super(AnalysisThread, self).__init__() 
     self.analysis = analysis 

    def run(self): 
     try: 
      process = Process(target=self.analysis.analyze) 
      process.start() 
      process.join() 
     except Exception as err: 
      exec_info = sys.exc_info() 
      self.processing_failed.emit(err, exec_info) 
     finally: 
      self.processing_ended.emit() 

class ProcessView(QtGui.QMainWindow): 

    def __init__(self): 
     super(ProcessView, self).__init__() 
     # Log Stream 
     self.stream = LogStream() 
     self.stream.messageWritten.connect(self.on_log_written) 

    def go(self): 
     analysis = MyAnalysis() 
     # Handler 
     handler = QtHandler(self.stream) 
     handler.setFormatter(logging.Formatter('(%(levelname)s-%(name)s) %(message)s')) 
     analysis.log.addHandler(handler) 
     self.processing = AnalysisThread(analysis) 
     self.processing.processing_ended.connect(self.on_processing_ended) 

self.processing.processing_failed.connect(self.on_processing_failed) 
     self.processing.start() 

    def on_log_written(self, msg): 
     print('Message: {}'.format(msg)) # never called 

编辑

为了澄清，这是一个多线程的应用程序，而且还多进程一个...

Answer 1

既然你在多线程环境中工作，尝试指定的Qt 。当你连接你的信号和插槽时，连接。

例如：

self.stream.messageWritten.connect(self.on_log_written, QtCore.Qt.QueuedConnection) 

Answer 2

ANSWER

我终于找到了解决方案。我的应用程序如上所述使用多处理，并且日志发生在子进程中，所以父进程永远不会警告信号。解决方案是在子代和父进程之间创建一个“链接”，其中包含multiprocessing.Pipe。实现可能是

class Streamer(QtCore.QThread): 
    messageWritten = QtCore.Signal(str) 

    def __init__(self, pipe): 
     super(Streamer, self).__init__() 
     self.pipe = pipe 

    def run(self): 
     while True: 
      try: 
       msg = self.pipe.recv() 
      except EOFError: 
       break 
      else: 
       self.messageWritten.emit(msg) 

class QtHandler(logging.Handler): 
    def __init__(self, stream): 
     """Instantiate handler 

     :param stream: multiprocessing.Pipe 
     """ 
     logging.Handler.__init__(self) 
     self.stream = stream 

    def emit(self, record): 
     record = self.format(record) 
     if record: 
      self.stream.send('%s\n' % record) 

class ProcessView(QtGui.QMainWindow): 

    def __init__(self): 
     super(ProcessView, self).__init__() 
     # Log Stream 
     mother_pipe, child_pipe = Pipe() 
     self.stream = child_pipe 
     self.streamer = Streamer(mother_pipe) 
     self.streamer.daemon = True 
     self.streamer.start() 
     self.streamer.messageWritten.connect(self.on_log_written) 

    def on_log_written(self, msg): 
     self.ui.textBrowser_log.insertPlainText(msg) 
     txt_max = self.ui.textBrowser_log.verticalScrollBar().maximum() 
     self.ui.textBrowser_log.verticalScrollBar().setValue(txt_max) 

说明：

主线程（GUI）开始。在初始化时，它会创建一个multiprocesing.Pipe来与子进程通信，还有一个监听管道结束的守护进程。所以在子进程启动后，它最终会记录一些内容。 QtHandler截取消息并通过管道发送。守护程序在管道的另一端收到消息，并通过信号messageWritten将其转发到GUI线程。最后，该信号由一个插槽处理，该插槽将其写入QTextBrowser，该滚动条被刷新为