带线程的 PyQt 进度条更新

Question

我一直在编写一个在服务器上运行远程脚本的程序。所以，我需要用一个栏显示进度，但是当我运行我的代码时，GUI 开始冻结。我使用过 QThread 和 SIGNAL 但很遗憾无法成功。

下面是我的代码；

class dumpThread(QThread):

    def __init__(self):
        QThread.__init__(self)

    def __del__(self):
        self.wait()

    def sendEstablismentCommands(self, connection):

        # Commands are sending sequently with proper delay-timers #

        connection.sendShell("telnet localhost 21000")
        time.sleep(0.5)
        connection.sendShell("admin")
        time.sleep(0.5)
        connection.sendShell("admin")
        time.sleep(0.5)
        connection.sendShell("cd imdb")
        time.sleep(0.5)
        connection.sendShell("dump subscriber")

        command = input('$ ')

    def run(self):
        # your logic here              
        # self.emit(QtCore.SIGNAL('THREAD_VALUE'), maxVal)
        self.sendEstablismentCommands(connection)    

class progressThread(QThread):

    def __init__(self):
        QThread.__init__(self)

    def __del__(self):
        self.wait()


    def run(self):
        # your logic here
        while 1:      
            maxVal = 100
            self.emit(SIGNAL('PROGRESS'), maxVal)

class Main(QtGui.QMainWindow):
    def __init__(self):
        QtGui.QMainWindow.__init__(self)
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)
        self.ui.connectButton.clicked.connect(self.connectToSESM)



    def connectToSESM(self):
        ## Function called when pressing connect button, input are being taken from edit boxes. ##
        ## dumpThread() method has been designed for working thread seperate from GUI. ##

        # Connection data are taken from "Edit Boxes"
        # username has been set as hardcoded

        ### Values Should Be Defined As Global ###
        username = "ntappadm"
        password = self.ui.passwordEdit.text()
        ipAddress = self.ui.ipEdit.text()

        # Connection has been established through paramiko shell library
        global connection

        connection = pr.ssh(ipAddress, username, password)
        connection.openShell()
        pyqtRemoveInputHook()  # For remove unnecessary items from console

        global get_thread

        get_thread = dumpThread() # Run thread - Dump Subscriber
        self.progress_thread = progressThread()

        self.progress_thread.start()
        self.connect(self.progress_thread, SIGNAL('PROGRESS'), self.updateProgressBar)

        get_thread.start()     




    def updateProgressBar(self, maxVal):

        for i in range(maxVal):
            self.ui.progressBar.setValue(self.ui.progressBar.value() + 1)
            time.sleep(1)
            maxVal = maxVal - 1

            if maxVal == 0:
                self.ui.progressBar.setValue(100)

    def parseSubscriberList(self):
        parsing = reParser()

    def done(self):
        QtGui.QMessageBox.information(self, "Done!", "Done fetching posts!")




if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    main = Main()
    main.show()
    sys.exit(app.exec_())

我希望看到 updateProgressBar 方法已通过 SIGNAL 调用，因此进程通过单独的线程。我找不到我失踪的地方。

感谢您的帮助

Answer 1

确实有两个问题。我注意到的一件事是，如果 Python 线程不用于 IO 操作（例如从串行端口读取），则它们是贪婪的。如果您告诉线程运行计算或与 IO 无关的东西，线程将占用所有处理并且不喜欢让主线程/事件循环运行。第二个问题是信号很慢……非常慢。我注意到如果你从一个线程发出一个信号并且非常快地执行它会大大减慢程序的速度。

所以问题的核心是，线程一直在占用所有时间，而您发出的信号非常非常快，这将导致速度变慢。

为了清晰和易于使用，我将使用新样式的信号和插槽。 http://pyqt.sourceforge.net/Docs/PyQt4/new_style_signals_slots.html

class progressThread(QThread):

    progress_update = QtCore.Signal(int) # or pyqtSignal(int)

    def __init__(self):
        QThread.__init__(self)

    def __del__(self):
        self.wait()


    def run(self):
        # your logic here
        while 1:      
            maxVal = 100
            self.progress_update.emit(maxVal) # self.emit(SIGNAL('PROGRESS'), maxVal)
            # Tell the thread to sleep for 1 second and let other things run
            time.sleep(1)

连接到新风格的信号

...
self.progress_thread.start()
self.process_thread.progress_update.connect(self.updateProgressBar) # self.connect(self.progress_thread, SIGNAL('PROGRESS'), self.updateProgressBar)
...

编辑 抱歉还有一个问题。当一个信号调用一个函数时，你不能永远留在那个函数中。该函数没有在单独的线程中运行，而是在主事件循环上运行，并且主事件循环等待运行，直到您退出该函数。

更新进度休眠 1 秒并不断循环。悬念来自于停留在这个函数中。

def updateProgressBar(self, maxVal):

    for i in range(maxVal):
        self.ui.progressBar.setValue(self.ui.progressBar.value() + 1)
        time.sleep(1)
        maxVal = maxVal - 1

        if maxVal == 0:
            self.ui.progressBar.setValue(100)

进度条最好写成这样

class progressThread(QThread):

    progress_update = QtCore.Signal(int) # or pyqtSignal(int)

    def __init__(self):
        QThread.__init__(self)

    def __del__(self):
        self.wait()


    def run(self):
        # your logic here
        while 1:      
            maxVal = 1 # NOTE THIS CHANGED to 1 since updateProgressBar was updating the value by 1 every time
            self.progress_update.emit(maxVal) # self.emit(SIGNAL('PROGRESS'), maxVal)
            # Tell the thread to sleep for 1 second and let other things run
            time.sleep(1)


def updateProgressBar(self, maxVal):
    self.ui.progressBar.setValue(self.ui.progressBar.value() + maxVal)
    if maxVal == 0:
        self.ui.progressBar.setValue(100)