Python PySide和进度条线程

Question

我有这个密码：

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_())

我想把进度条放在一个单独的线程中，这样它就不会冻结应用程序，但我似乎找不到这样做的方法。

有人能帮忙吗？

Answer 1

我想你可能弄错了。你需要在一个单独的线程中完成工作，这样它就不会冻结应用程序。但您也希望能够更新进度条。您可以通过使用QThread创建工作类来实现这一点。qthread能够发出信号，用户界面可以监听这些信号并采取适当的操作。

首先，让我们创建你的工人阶级。

#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)

现在你有了工人阶级，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出的信号。

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

在那里时，可以删除progress()函数。

在retranslateUi()中，您将希望从

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

到

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

最后，在setupUI()函数中，需要创建一个worker类的实例，并将其信号连接到setProgress()函数。

在此之前：

self.retranslateUi(Dialog)

添加以下内容：

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

---

以下是最终代码：

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有一些自动发出的内置信号。您可以看到它们，以及有关QThreadsin the documentation的更多信息

Answer 2

认为总是需要使用多线程来处理这样的事情是错误的。

如果您可以将长期运行的任务分解为一系列的小步骤，那么您所需要做的就是确保所有挂起的事件都得到足够频繁的处理，以便GUI保持响应。这可以通过使用processEvents从主GUI线程中的安全地完成，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，在选择更重的解决方案（如多线程或多处理）之前，至少应该考虑一下这种技术。