progress bar

import sys
from time import sleep

from PyQt4.QtCore import *
from PyQt4.QtGui import *

mainLoopCount = 10
innerLoopCount = 1000
durationInnerLoop = 4.0 # seconds (float!)



class dialog(QDialog):
    progress = 0
    def __init__(self):
        QDialog.__init__(self)
        layout = QGridLayout(self)
        self.progressBar = QProgressBar(self)
        layout.addWidget(self.progressBar,0,0)
        button = QPushButton("start")
        button.clicked.connect(self.start)
        layout.addWidget(button,0,1)
        self.progressBar.setMinimum(0)
        self.progressBar.setMaximum(mainLoopCount)

    def start(self):
        for i in range(0,10):
            QCoreApplication.processEvents()
            self.progress = i
            self.setProgress()
            worker = Worker()
            worker.progress.connect(self.setProgress)
            worker.work()

    def setProgress(self,value=0):
        p = self.progress + float(value) / innerLoopCount
        print p
        self.progressBar.setValue(p)



class Worker(QObject):
    progress = pyqtSignal(int)

    def __init__(self):
        QObject.__init__(self)

    def work(self):
        for i in range(0,1000):
            QCoreApplication.processEvents()
            sleep(durationInnerLoop/innerLoopCount)
            self.progress.emit(i)



if __name__ == "__main__":
    app = QApplication(sys.argv)
    main_window = dialog()
    main_window.show()
    sys.exit(app.exec_())