带线程的 PyQt 进度条更新

Question

我一直在编写一个程序，该程序运行是服务器上的远程脚本。所以，我需要用一个栏来显示进度，但是不知何故，当我运行我的代码时，GUI 开始冻结。我已经使用了 QThread 和 SIGNAL，但不幸的是无法成功。

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 Python 线程如果不用于 IO 操作（如从串行端口读取），则它们是贪婪的。如果你告诉一个线程运行一个计算或一些与 IO 无关的东西，一个线程将占用所有的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，如果您从线程发出信号并且速度非常快，它会大大降低程序速度。

所以问题的核心是，线程一直在占用所有时间，并且您正在非常非常快地发出信号，这会导致速度变慢。

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)

连接新式信号

...
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。该函数不在单独的线程中运行ning 它在主事件循环中运行ning 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，一直循环。挂起是因为停留在这个函数中。

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)

进度条最好这样写

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)

带线程的 PyQt 进度条更新

PyQt Progress Bar Update with Threads

python

user-interface

pyqt

signals-slots

qthread