Kivy ScreenManager 不切换屏幕（纯python）

Question

我对 Kivy 很陌生，我遇到了一个我自己无法解决的问题。 我有一个简单的应用程序，我想在图像之间切换（MainScreen）。

这是代码：

IMAGE_SIZE = (640, 480)

class MainScreen(Screen):

    def __init__(self, path, **kwargs):
        super(MainScreen, self).__init__(**kwargs)
        Window.size = (IMAGE_SIZE[0], IMAGE_SIZE[1])


        with self.canvas:
            self.bg = Image(path)
            self.bind(pos=self.update_bg)
            self.bind(size=self.update_bg)

        self._keyboard = Window.request_keyboard(
            self._keyboard_closed, self, 'text')

        self._keyboard.bind(on_key_down=self._on_keyboard_down)

    def update_bg(self, *args):
        self.bg.pos = self.pos
        self.bg.size = self.size

    def _keyboard_closed(self):
        print('My keyboard have been closed!')
        self._keyboard.unbind(on_key_down=self._on_keyboard_down)
        self._keyboard = None

    def _on_keyboard_down(self, keyboard, keycode, text, modifiers):
        if keycode[1] == 'escape':
            keyboard.release()
        if keycode[1] == 'enter':


            print('before enter', screen_manager.current_screen)
            screen_manager.transition.direction = 'left'
            screen_manager.current_screen = scree_1
            print('after enter',screen_manager.current_screen)


        return True


screen_manager = None

scree_1 = MainScreen(path_1, name="1")
scree_2 = MainScreen(path_2, name="2")


class MyApp(App):

    def build(self):
        global screen_manager
        screen_manager = ScreenManager()

        screen_manager.add_widget(scree_2)
        screen_manager.add_widget(scree_1)

        return screen_manager


if __name__ == '__main__':
    MyApp().run()

我做了一个打印，看看屏幕管理器是否有变化：

打印的结果

在我看来，经理确实改变了屏幕，但我仍然是同样的画面。

我已经看过这个问题，但没有发现任何帮助。

如果有人知道我做错了什么，我将不胜感激任何帮助/建议。

更新：

@JohnAnderson 在评论中注意到，我应该交换屏幕的名称，而不是屏幕本身，但是没有任何改变。

Answer 1

您必须操作的是screen_manager.current而不是screen_manager.current_screen 。
您还必须通过其名称来引用screen 。

这是你的代码，工作：

IMAGE_SIZE = (640, 480)


class MainScreen(Screen):

    def __init__(self, path, **kwargs):
        super(MainScreen, self).__init__(**kwargs)
        Window.size = (IMAGE_SIZE[0], IMAGE_SIZE[1])

        with self.canvas:
            self.bg = Image(source=path)
            self.bind(pos=self.update_bg)
            self.bind(size=self.update_bg)

        self._keyboard = Window.request_keyboard(self._keyboard_closed, self, 'text')

        self._keyboard.bind(on_key_down=self._on_keyboard_down)

    def update_bg(self, *args):
        self.bg.pos = self.pos
        self.bg.size = self.size

    def _keyboard_closed(self):
        print('My keyboard have been closed!')
        self._keyboard.unbind(on_key_down=self._on_keyboard_down)
        self._keyboard = None

    def _on_keyboard_down(self, keyboard, keycode, text, modifiers):
        if keycode[1] == 'escape':
            keyboard.release()
        if keycode[1] == 'enter':
            print('before enter', screen_manager.current)
            screen_manager.transition.direction = 'left'
            screen_manager.current = "1"
            print('after enter', screen_manager.current)

        return True


screen_manager = None

scree_1 = MainScreen(path_1, name="1")
scree_2 = MainScreen(path_2, name="2")


class MyApp(App):

    def build(self):
        global screen_manager
        screen_manager = ScreenManager()

        screen_manager.add_widget(scree_2)
        screen_manager.add_widget(scree_1)

        return screen_manager


if __name__ == '__main__':
    MyApp().run()

Answer 2

经过一番挖掘，我找到了另一个答案。 我还可以使用：

            screen_manager.switch_to(screen_1, direction='left')