Python PyQt4.QtGui 模块，QStackedWidget() 实例源码

def __init__(self, controller, position, *args, **kwargs):
        super(Panel, self).__init__(position.title(), *args, **kwargs)
        self.instructions = controller
        self.position = position.lower()

        layout = QtGui.QVBoxLayout()
        self.selector = QtGui.QComboBox()
        self.selector.currentIndexChanged.connect(self.on_selector)

        layout.addWidget(self.selector)
        self.stack = QtGui.QStackedWidget()
        layout.addWidget(self.stack)
        self.setLayout(layout)

        for cls in screen.ScreenWidget.__subclasses__():
            self.selector.addItem(cls.name)
            self.stack.addWidget(cls(controller, position))