Python PySide和进度条线程

Question

我有这段代码：

from PySide import QtCore, QtGui
import time

class Ui_Dialog(object):
    def setupUi(self, Dialog):
        Dialog.setObjectName("Dialog")
        Dialog.resize(400, 133)
        self.progressBar = QtGui.QProgressBar(Dialog)
        self.progressBar.setGeometry(QtCore.QRect(20, 10, 361, 23))
        self.progressBar.setProperty("value", 24)
        self.progressBar.setObjectName("progressBar")
        self.pushButton = QtGui.QPushButton(Dialog)
        self.pushButton.setGeometry(QtCore.QRect(20, 40, 361, 61))
        self.pushButton.setObjectName("pushButton")

        self.retranslateUi(Dialog)
        QtCore.QMetaObject.connectSlotsByName(Dialog)

    def retranslateUi(self, Dialog):
        Dialog.setWindowTitle(QtGui.QApplication.translate("Dialog", "Dialog", None, QtGui.QApplication.UnicodeUTF8))
        self.pushButton.setText(QtGui.QApplication.translate("Dialog", "PushButton", None, QtGui.QApplication.UnicodeUTF8))
        self.progressBar.setValue(0)
        self.pushButton.clicked.connect(self.progress)

    def progress(self):
        self.progressBar.minimum = 1
        self.progressBar.maximum = 100
        for i in range(1, 101):
            self.progressBar.setValue(i)
            time.sleep(0.1)

if __name__ == "__main__":
    import sys
    app = QtGui.QApplication(sys.argv)
    Dialog = QtGui.QDialog()
    ui = Ui_Dialog()
    ui.setupUi(Dialog)
    Dialog.show()
    sys.exit(app.exec_())

我希望将进度条放在一个单独的线程中，以避免它冻结应用程序，但我似乎找不到如何实现。

请问有人能帮忙吗？

- Benny

Answer 1

我认为你可能误解了。你想要将你正在进行的工作放在单独的线程中，这样它就不会冻结应用程序。但是你还想能够更新进度条。你可以通过使用QThread创建一个工作类来实现这一点。QThreads能够发出信号，你的UI可以监听并采取适当的行动。

首先，让我们创建你的工作类。

#Inherit from QThread
class Worker(QtCore.QThread):

    #This is the signal that will be emitted during the processing.
    #By including int as an argument, it lets the signal know to expect
    #an integer argument when emitting.
    updateProgress = QtCore.Signal(int)

    #You can do any extra things in this init you need, but for this example
    #nothing else needs to be done expect call the super's init
    def __init__(self):
        QtCore.QThread.__init__(self)

    #A QThread is run by calling it's start() function, which calls this run()
    #function in it's own "thread". 
    def run(self):
        #Notice this is the same thing you were doing in your progress() function
        for i in range(1, 101):
            #Emit the signal so it can be received on the UI side.
            self.updateProgress.emit(i)
            time.sleep(0.1)

现在您已经有了一个 worker 类，是时候利用它了。 您需要在 Ui_Dialog 类中创建一个新函数来处理发射的信号。

def setProgress(self, progress):
    self.progressBar.setValue(progress)

当您在那里时，您可以删除 progress() 函数。

在 retranslateUi() 中，您需要更新推按钮事件处理程序：

self.pushButton.clicked.connect(self.progress)

到

self.pushButton.clicked.connect(self.worker.start)

最后，在您的setupUI()函数中，您需要创建一个工作类的实例，并将其信号连接到setProgress()函数。

在此之前：

self.retranslateUi(Dialog)

请添加以下内容：

self.worker = Worker()
self.worker.updateProgress.connect(self.setProgress)

---

这是最终代码：

from PySide import QtCore, QtGui
import time


class Ui_Dialog(object):
    def setupUi(self, Dialog):
        Dialog.setObjectName("Dialog")
        Dialog.resize(400, 133)
        self.progressBar = QtGui.QProgressBar(Dialog)
        self.progressBar.setGeometry(QtCore.QRect(20, 10, 361, 23))
        self.progressBar.setProperty("value", 24)
        self.progressBar.setObjectName("progressBar")
        self.pushButton = QtGui.QPushButton(Dialog)
        self.pushButton.setGeometry(QtCore.QRect(20, 40, 361, 61))
        self.pushButton.setObjectName("pushButton")

        self.worker = Worker()
        self.worker.updateProgress.connect(self.setProgress)

        self.retranslateUi(Dialog)
        QtCore.QMetaObject.connectSlotsByName(Dialog)

        self.progressBar.minimum = 1
        self.progressBar.maximum = 100

    def retranslateUi(self, Dialog):
        Dialog.setWindowTitle(QtGui.QApplication.translate("Dialog", "Dialog", None, QtGui.QApplication.UnicodeUTF8))
        self.pushButton.setText(QtGui.QApplication.translate("Dialog", "PushButton", None, QtGui.QApplication.UnicodeUTF8))
        self.progressBar.setValue(0)
        self.pushButton.clicked.connect(self.worker.start)

    def setProgress(self, progress):
        self.progressBar.setValue(progress)

#Inherit from QThread
class Worker(QtCore.QThread):

    #This is the signal that will be emitted during the processing.
    #By including int as an argument, it lets the signal know to expect
    #an integer argument when emitting.
    updateProgress = QtCore.Signal(int)

    #You can do any extra things in this init you need, but for this example
    #nothing else needs to be done expect call the super's init
    def __init__(self):
        QtCore.QThread.__init__(self)

    #A QThread is run by calling it's start() function, which calls this run()
    #function in it's own "thread". 
    def run(self):
        #Notice this is the same thing you were doing in your progress() function
        for i in range(1, 101):
            #Emit the signal so it can be received on the UI side.
            self.updateProgress.emit(i)
            time.sleep(0.1)

if __name__ == "__main__":
    import sys
    app = QtGui.QApplication(sys.argv)
    Dialog = QtGui.QDialog()
    ui = Ui_Dialog()
    ui.setupUi(Dialog)
    Dialog.show()
    sys.exit(app.exec_())

---

QThreads有一些内置信号会自动发出。你可以在文档中查看这些信号，以及更多关于QThreads的信息。

---

- smont

---

这并不完美，因为没有锁定GUI。例如，如果在进度条更新时打开QFileDialog，它只会停止QThread。 - greendino

Answer 2

认为你总是需要像这样使用多线程是错误的。

如果您可以将长时间运行的任务分解为一系列小步骤，则只需要确保任何挂起的事件被充分处理，以使GUI保持响应性。 这可以通过在主GUI线程内使用processEvents来安全地完成，如下所示：

    for i in range(1, 101):
        self.progressBar.setValue(i)
        QtGui.qApp.processEvents()
        time.sleep(0.1)

考虑到它的简单性，通常值得在选择更加复杂的解决方案（如多线程或多进程）之前至少考虑一下这种技术。

- ekhumoro

---

注意，time.sleep仅用于测试目的。不适用于Qt。 - greendino