小部件未包含在QtGui.QMainWindow中

Question

嗨，

这里有PySide / PyQt4新手。 我们正在将OpenCasCade查看器后端从X11移植到Cocoa。 我无法理解为什么我的小部件不包含在QtGui.QMainWindow中...... 非常感谢任何指向我应该关注的内容......作为PySide的新手，API的范围可能有点压倒性;）

    from qtDisplay import qtViewer3d

    class MainWindow(QtGui.QMainWindow):
        def __init__(self, *args):
            apply(QtGui.QMainWindow.__init__,(self,)+args)
            self.canva = qtViewer3d(self) # QtGui.QWidget instance
            self.setWindowTitle("pythonOCC-%s 3d viewer ('qt' backend)"%VERSION)
            self.setCentralWidget(self.canva)
            self.resize(1024,768)
            self.menuBar = self.menuBar()
            self._menus = {}
            self._menu_methods = {}

        def add_menu(self, menu_name):
            _menu = self.menuBar.addMenu("&"+menu_name)
            self._menus[menu_name]=_menu

        def add_function_to_menu(self, menu_name, _callable):
            assert callable(_callable), 'the function supplied is not callable'
            try:
                _action = QtGui.QAction(_callable.__name__.replace('_', ' ').lower(), self)
                self.connect(_action, QtCore.SIGNAL("triggered()"), _callable)
                self._menus[menu_name].addAction(_action)
            except KeyError:
                raise ValueError('the menu item %s does not exist' % (menu_name))
    app = QtGui.QApplication(sys.argv)
    win = MainWindow()
    win.canva.InitDriver()
    win.show()
    display = win.canva._display
    display.SetBackgroundImage(get_bg_abs_filename())        
    def add_menu(*args, **kwargs):
        win.add_menu(*args, **kwargs)
    def add_function_to_menu(*args, **kwargs):
        win.add_function_to_menu(*args, **kwargs)
    def start_display():
        app.exec_()