main.py 文件源码

def load_screen(self, screen, manager=None, store_back=True):
        '''Load the provided screen:
        arguments::
            `screen`: is the name of the screen to be loaded
            `manager`: the manager to load this screen, this defaults to
            the main class.
        '''
        store_back = False if screen == 'StartupScreen' else store_back

        manager = manager or self.root
        # load screen modules dynamically
        # for example load_screen('LoginScreen')
        # will look for uix/screens/loginscreen
        # load LoginScreen 
        module_path = screen.lower()
        if not hasattr(self, module_path):
            import imp
            module = imp.load_module(screen, *imp.find_module(module_path))
            screen_class = getattr(module, screen)
            sc = screen_class() 
            sc.from_back = not store_back
            setattr(self, module_path, sc)
            manager.add_widget(sc)

        else:
            sc = getattr(self, module_path)

        sc.from_back = not store_back
        manager.current = screen

        if store_back:
            self._navigation_higherarchy.append(sc)

        return getattr(self, module_path)

# Check if app is started as main and only then insitantiate the App class.