import sys from PyQt4 import QtGui, QtCore class Window( QtGui.QMainWindow):     def __init__(self):         QtGui.QMainWindow.__init__(self)         self.setWindowTitle('hello')         self.resize(800,500)         menubar = self.menuBar()         self.file = menubar.addMenu('&file')         open = self.file.addAction('open')         self.connect(open,QtCore.SIGNAL('triggered()'),self.OnOpen)         save =self.file.addAction('save')         self.connect(save,QtCore.SIGNAL('triggered()'),self.OnSave)         self.file.addSeparator()         close = self.file.addAction('close')         self.connect(close,QtCore.SIGNAL('triggered()'),self.OnClose)         self.label = QtGui.QLabel('this is a google text')         self.label.setAlignment(QtCore.Qt.AlignCenter)         self.setCentralWidget(self.label)     def OnOpen(self):         self.label.setText('open')     def OnClose(self):         self.close()     def OnSave( self):         self.label.setText('save')     def contextMenuEvent(self,event):         self.file.exec_( event.globalPos()) app =QtGui.QApplication(sys.argv) win = Window() win.show() app.exec_()