Progress Bar Test | Python Fiddle

from PySide import QtCore, QtGui
import shiboken
import maya.OpenMayaUI as omui

def getMainWindow():
    ptr = omui.MQtUtil.mainWindow()
    qObj = shiboken.wrapInstance(long(ptr), QtCore.QObject)
    metaObj = qObj.metaObject()
    cls = metaObj.className()
    superCls = metaObj.superClass().className()
    if hasattr(QtGui, cls):
        base = getattr(QtGui, cls)
    elif hasattr(QtGui, superCls):
        base = getattr(QtGui, superCls)
    else:
        base = QtGui.QWidget
    mainWin = shiboken.wrapInstance(long(ptr), base)
    return mainWin

class PBTester(QtCore.QObject):
    processStarted = QtCore.Signal(int, str, int, int)
    processUpdated = QtCore.Signal(int, int)
    processCompleted = QtCore.Signal(int)
    task1Finished = QtCore.Signal()
    task2Finished = QtCore.Signal()

def __init__(self, parent=None):
        super(PBTester, self).__init__(parent)

self.cancel = False

def RunTasks(self):
        loop = QtCore.QEventLoop()
        self.processStarted.emit(0, "Primary Task", 0, 3)
        for obj in range(3):
            self.processUpdated.emit(0, obj)
            self.task1Finished.connect(loop.quit)
            QtCore.QTimer.singleShot(0, self._runTask1)
            loop.exec_()
            self.task1Finished.disconnect(loop.quit)
            self.task2Finished.connect(loop.quit)
            QtCore.QTimer.singleShot(0, self._runTask2)
            loop.exec_()
            self.task2Finished.disconnect(loop.quit)
        self.processCompleted.emit(0)

def _runTask1(self):
        self.processStarted.emit(1, "First Subtask", 0, 1000)
        for index in range(1000):
            self.processUpdated.emit(1, index)
        self.processCompleted.emit(1)
        self.task1Finished.emit()

def _runTask2(self):
        self.processStarted.emit(1, "Second Subtask", 0, 1000)
        for index in range(1000):
            self.processUpdated.emit(1, index)
        self.processCompleted.emit(1)
        self.task2Finished.emit()

@QtCore.Slot()
    def Process(self):
        self.RunTasks()
        self.finished.emit()

def __repr__(self):
        pass

class PBUI(QtGui.QMainWindow):
    def __init__(self, parent=None):
        if parent is None:
            parent = getMainWindow()
        super(PBUI, self).__init__(parent)

self.progressBars = []
        self.progressBarLayouts = []

widget = QtGui.QWidget()
        self.layout = QtGui.QVBoxLayout()

button = QtGui.QPushButton("Run Progress Bars")
        button.clicked.connect(self.runTests)
        self.layout.addWidget(button)

self.pbLayout = QtGui.QVBoxLayout()
        self.layout.addLayout(self.pbLayout)

widget.setLayout(self.layout)
        self.setCentralWidget(widget)
        self.show()

def runTests(self):
        self.WorkerObject = PBTester()
        self.WorkerObject.processStarted.connect(self.addProgressBar)
        self.WorkerObject.processUpdated.connect(self.updateProgressBar)
        self.WorkerObject.processCompleted.connect(self.removeProgressBar)
        self.WorkerObject.RunTasks()

@QtCore.Slot(int, str, int, int)
    def addProgressBar(self, index, name, min, max):
        widget = QtGui.QWidget()
        layout = QtGui.QVBoxLayout()
        label = QtGui.QLabel(name)
        layout.addWidget(label)
        progBar = QtGui.QProgressBar()
        progBar.setRange(min, max)
        layout.addWidget(progBar)
        widget.setLayout(layout)
        self.pbLayout.addWidget(widget)
        self.progressBars.insert(index, progBar)
        self.progressBarLayouts.insert(index, widget)
        QtGui.QApplication.processEvents()
        self.update()

@QtCore.Slot(int, int)
    def updateProgressBar(self, index, value):
        progBar = self.progressBars[index]
        progBar.setValue(value)
        QtGui.QApplication.processEvents()
        self.update()

@QtCore.Slot(int)
    def removeProgressBar(self, index):
        progBarWidget = self.progressBarLayouts.pop(index)
        self.progressBars.pop(index)
        self.pbLayout.takeAt(index)
        progBarWidget.deleteLater()
        QtGui.QApplication.processEvents()
        self.update()

if __name__ == '__main__':
    import sys
    app = QtGui.QApplication(sys.argv)
    win = QtGui.QWidget()
    PBUI(win)
    win.show()
    sys.exit(app.exec_())

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