休眠工作线程会导致主GUI冻结

Question

Sleeping the worker thread causes main gui to freeze.

What I want to do is:

1. Sleep the worker thread (MyThread)and start the next iteration after some period.
2. Once MyThread goes into sleep, click on cancel, and cancel the ongoing operation.

In my case the main operation gets canceled when MyThread wakes up again. I wanted it to be cancelled immediately.

import sys
from PyQt4 import QtGui, QtCore
import time


try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
    _fromUtf8 = lambda s: s


class Ui_dialog_progress(object):
    def setupUi(self, dialog_progress):
        dialog_progress.setObjectName("dialog_progress")
        dialog_progress.resize(401, 165)
        self.gridLayout = QtGui.QGridLayout(dialog_progress)
        self.gridLayout.setObjectName("gridLayout")
        self.lblFileName = QtGui.QLabel(dialog_progress)
        self.lblFileName.setText("")
        self.lblFileName.setObjectName("lblFileName")
        self.gridLayout.addWidget(self.lblFileName, 0, 0, 1, 2)
        self.pbarFileSize = QtGui.QProgressBar(dialog_progress)
        self.pbarFileSize.setProperty("value", 0)
        self.pbarFileSize.setObjectName("pbarFileSize")
        self.gridLayout.addWidget(self.pbarFileSize, 1, 0, 1, 2)
        self.label_2 = QtGui.QLabel(dialog_progress)
        self.label_2.setObjectName("label_2")
        self.gridLayout.addWidget(self.label_2, 2, 0, 1, 1)
        self.pbarTotal = QtGui.QProgressBar(dialog_progress)
        self.pbarTotal.setProperty("value", 0)
        self.pbarTotal.setObjectName("pbarTotal")
        self.gridLayout.addWidget(self.pbarTotal, 3, 0, 1, 2)
        self.lblTotal = QtGui.QLabel(dialog_progress)
        self.lblTotal.setText("")
        self.lblTotal.setObjectName("lblTotal")
        self.gridLayout.addWidget(self.lblTotal, 4, 0, 1, 2)
        spacerItem = QtGui.QSpacerItem(213, 20, QtGui.QSizePolicy.Expanding, QtGui.QSizePolicy.Minimum)
        self.gridLayout.addItem(spacerItem, 6, 0, 1, 1)
        spacerItem1 = QtGui.QSpacerItem(20, 5, QtGui.QSizePolicy.Minimum, QtGui.QSizePolicy.Expanding)
        self.gridLayout.addItem(spacerItem1, 5, 1, 1, 1)
        self.btnPbarCancel = QtGui.QPushButton(dialog_progress)
        self.btnPbarCancel.setObjectName("btnPbarCancel")
        self.gridLayout.addWidget(self.btnPbarCancel, 6, 1, 1, 1)

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

    def retranslateUi(self, dialog_progress):
        dialog_progress.setWindowTitle(QtGui.QApplication.translate("dialog_progress", "Dialog", None, QtGui.QApplication.UnicodeUTF8))
        self.label_2.setText(QtGui.QApplication.translate("dialog_progress", "Total:", None, QtGui.QApplication.UnicodeUTF8))
        self.btnPbarCancel.setText(QtGui.QApplication.translate("dialog_progress", "Cancel", None, QtGui.QApplication.UnicodeUTF8))

class Ui_dialog_file(object):
    def setupUi(self, dialog_file):
        dialog_file.setObjectName(_fromUtf8("dialog_file"))
        dialog_file.resize(101, 59)
        self.btnCreate = QtGui.QPushButton(dialog_file)
        self.btnCreate.setGeometry(QtCore.QRect(10, 20, 77, 25))
        self.btnCreate.setObjectName(_fromUtf8("btnCreate"))
        self.retranslateUi(dialog_file)
        QtCore.QMetaObject.connectSlotsByName(dialog_file)

    def retranslateUi(self, dialog_file):
        dialog_file.setWindowTitle(QtGui.QApplication.translate("dialog_file", "file", None, QtGui.QApplication.UnicodeUTF8))
        self.btnCreate.setText(QtGui.QApplication.translate("dialog_file", "Create", None, QtGui.QApplication.UnicodeUTF8))

class ProgressDialog(QtGui.QDialog):
    def __init__(self, parent=None):
        QtGui.QDialog.__init__(self, parent = None)
        self.ui = Ui_dialog_progress()
        self.ui.setupUi(self)
#        self.setWindowModality(QtCore.Qt.ApplicationModal)

class MyThread(QtCore.QThread):
    trigger = QtCore.pyqtSignal()
    updateFPD = QtCore.pyqtSignal(int, QtCore.QString)
    updateTPD = QtCore.pyqtSignal(int, QtCore.QString)
    showpdSignal = QtCore.pyqtSignal(bool)

    def __init__(self, parent=None, no=0):
        super(MyThread, self).__init__(parent)
        self.aborted= False
        self.threadNo = no
#        self.name = "Thread %d"%self.threadNo

    def run(self):
        self.trigger.emit()

    def emitSignals(self, iprogress = -99, tprogress = -99,\
                updateFPDSignal = True, updateTPDSignal = None,\
                showpdSignal = False, peSignal = None, msg = None
                ):
        if updateFPDSignal:
            self.updateFPD.emit(iprogress, msg)
        if updateTPDSignal:
            self.updateTPD.emit(tprogress, msg)
        if showpdSignal:
            self.showpdSignal.emit(True)
        else:
            self.showpdSignal.emit(False)
        if peSignal:
            QtGui.QApplication.processEvents()

    def abort(self):
        self.aborted = True
        print "aborted"

    def stop(self):
        self.terminate()

class Main(QtGui.QDialog):
    def __init__(self, parent=None):
        super(Main, self).__init__(parent)
        self.ui = Ui_dialog_file()
        self.ui.setupUi(self)
        self.ui.btnCreate.clicked.connect(self.start_threads)
        self.count = 0

    def start_threads(self):
        self.mythread = MyThread()
        self.pd = ProgressDialog()
        signal = QtCore.SIGNAL("clicked()")
        self.pd.ui.btnPbarCancel.connect(self.pd.ui.btnPbarCancel, signal, self.abort)
        self.mythread.trigger.connect(self.pdialog)
        self.mythread.updateFPD.connect(self.updateFileProgress)
        self.mythread.updateTPD.connect(self.updateTotalProgress)
        self.mythread.start()

    def abort(self):
        self.pd.close()
        self.mythread.aborted = True

    def updateFileProgress(self, j, name):
        self.pd.ui.lblFileName.setText(name)
        self.pd.ui.pbarFileSize.setValue(j)
        print "name: %s, fileprogress: %d"%(name,j)

    def updateTotalProgress(self, i, name):
        self.pd.ui.pbarTotal.setValue(i)
        print "name: %s, total progress %d"%(name, i)

    def showProgressDialog(self, show):
        if show:
            self.pd.show()
        else:
            self.pd.close()

    def pdialog(self):
        for k in range(3):
            self.pd.show()
            i = 1
            self.mythread.emitSignals(iprogress =0 , tprogress = 0, updateFPDSignal = True,
                                      updateTPDSignal = True, showpdSignal = True, msg = "")
            j = 1
            while i < 100:
                while j <= 100:
                    print j
                    self.mythread.emitSignals(iprogress = j, updateFPDSignal = True,\
                                              peSignal = True, msg = "")
                    j += 1
                i += 1
                j = 1
                self.mythread.emitSignals(tprogress = i, updateTPDSignal = True,\
                                              peSignal = True, msg = "")
                if self.mythread.aborted:
                    return
            self.mythread.sleep(10)
            self.pd.close()

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

Answer 1

Your MyThread doesn't really do anything, as you can see if you look at it's run method. All other methods are still called from the main thread and therefore still happen there.

Please read Qt Threading Basics , specially the section about QObjects and threads, it should make it clear why the way you're using QThreads is ont working.

What you probably really want to do is:

• make your worker a normal QObject
• start a new QThread
• move your worker to that thread using the moveToThread method
• interact with it from your main thread using signals