【问题标题】:How run two different threads simultaneously in pyqt如何在pyqt中同时运行两个不同的线程
【发布时间】:2012-12-04 06:08:22
【问题描述】:

我有一种情况,我需要一个接一个地启动两个线程。我尝试了以下代码sn-p,在这里我可以启动Thread12但无法启动Thread2。我怎样才能同时开始......? 如何彼此启动 2 个线程...?

代码 sn-p

class Thread1(QtCore.QThread):

    Thread1Signal = QtCore.pyqtSignal(str)

    def __init__(self):
        super(Thread1, self).__init__()

    def run(self):
        print 'Thread1 started'
        While True:

            #some statments
            if Condition:
                Thread1Signal.emit('Yes')
            else:
                Thread1Signal.emit('No')

class Thread2(QtCore.QThread):

    Thread2Signal = QtCore.pyqtSignal(str)

    def __init__(self):
        super(Thread2, self).__init__()

    def run(self):
        print 'Thread2 started'
        While True:

            #some statments
            if Condition:
                Thread2Signal.emit('Yes')
            else:
                Thread2Signal.emit('No')

class MainClass(QtCore.QObject):

    MainSignal1 = QtCore.pyqtSignal(str)
    MainSignal2 = QtCore.pyqtSignal(str)

    def __init__(self):
        super(MainClass, self).__init__()   

        Threadinstance1 = Thread1()
        Threadinstance1.Thread1Signal.connect(MainSignal1)

        Threadinstance2 = Thread2()
        Threadinstance2.Thread2Signal.connect(MainSignal2)


   def start(self):

       Threadinstance1.start()
       Threadinstance2.start()                #Thread2 never starts.

def signal1called(s):

    print s


def signal2called(s):

    print s

if __name__=='__main__':
    app = AtGui.QApplication(sys.argv)
    temp = MainClass()
    temp.MainSignal1.connect(signal1called)
    temp.MainSignal2.connect(signal2called)
    temp.start()
    sys.exit(app.exec()_)

【问题讨论】:

  • 您确定您的测试用例的线程运行时间足以让您看到发出的信号吗?您在启动事件循环之前启动线程。它们实际上是在循环中运行,发出远远超出事件循环开始的信号,还是它们完成得太快?

标签: python multithreading qt pyqt pyqt4


【解决方案1】:

您将使用QRunnableQThreadPool,如下所示:

import sys

from PyQt4.QtGui import QApplication
from PyQt4.QtCore import QThreadPool, QObject, QRunnable, pyqtSignal

class WorkerSignals(QObject):
    result = pyqtSignal(int)

class Worker(QRunnable):
    def __init__(self, task):
        super(Worker, self).__init__()

        self.task = task
        self.signals = WorkerSignals()

    def run(self):
        print 'Sending', self.task
        self.signals.result.emit(self.task)

class Tasks(QObject):
    def __init__(self):
        super(Tasks, self).__init__()

        self.pool = QThreadPool()
        self.pool.setMaxThreadCount(1)

    def process_result(self, task):
        print 'Receiving', task

    def start(self):
        for task in range(10):
            worker = Worker(task)
            worker.signals.result.connect(self.process_result)

            self.pool.start(worker)

        self.pool.waitForDone()

if __name__ == "__main__":
    import  sys

    app = QApplication(sys.argv)
    main = Tasks()
    main.start()
    sys.exit(app.exec_())

【讨论】:

  • 您可以创建任意数量的Worker 类,从QRunnable 继承而不是QThread,然后从Tasks 调用
  • 您的意思是我们不能使用QThread 进行查询...?相反,我需要使用QRunnableQRunnableQThread 之间的区别是什么
  • 你可以,但是如果你想让它们一个一个运行,你可以使用QThreadPool,它需要QRunnable而不是QThread,或者发送一个来自每个 QThread 的 processEnded 信号,并将其连接到开始下一个 QThread 的插槽
  • 实际上我需要两个线程同时启动....所以,教导一个接一个地启动。但不要在完成另一个之后再开始。
  • 同时启动QThreads应该没有问题,如果不能,请重新检查您的实际代码,但您仍然可以使用QThreadPool,只需跳过self.pool.setMaxThreadCount(1)部分跨度>
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