如何使用纯Python编写的Kivy在2个屏幕之间切换？

Question

What I'm trying to do is create two screens, each with two buttons. One button switches to the other screen, and the other button just executes some code (just a print statement right now). I can't quite figure out how I'm supposed to be tying a name to a screen, because when I try and switch screens with my button I get the error

kivy.uix.screenmanager.ScreenManagerException: No Screen with name "screen2"

I tried printing out the name of the screens I created, and I just get

['', '']

So I assume that the two screens I made were created, but my attempt to name them failed.

Here's my full code:

#PYTHON 3.4.4
#KIVY 1.9.1


from kivy.app import App
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.screenmanager import ScreenManager, Screen


class ScreenOne(Screen):

    def __init__(self, **kwargs):
        super().__init__()

        btn1 = Button(
            text='change screen',
            size_hint=(.5, .25),
            pos_hint={'left':0, 'top':1}
            )
        btn1.bind(on_press=self.changer)
        self.add_widget(btn1)

        other_btn1 = Button(
            text='test button',
            size_hint=(.5, .25),
            pos_hint={'right':1, 'bottom':0}
            )
        other_btn1.bind(on_press=self.test)
        self.add_widget(other_btn1)


    def changer(self,*args):

        self.manager.current = 'screen2'

    def test(self,instance):
        print('This is a test')



class ScreenTwo(Screen):

    def __init__(self, **kwargs):
        super().__init__()

        btn2 = Button(
            text='change screen',
            size_hint=(.5, .25),
            pos_hint={'left':0, 'top':1}
            )
        btn2.bind(on_press=self.changer)
        self.add_widget(btn2)


        other_btn2 = Button(
            text='test button 2',
            size_hint=(.5, .25),
            pos_hint={'right':1, 'bottom':0}
            )
        other_btn2.bind(on_press=self.test)
        self.add_widget(other_btn2)


    def changer(self,*args):
        self.manager.current = 'screen1'

    def test(self,instance):
        print('This is another test')




class TestApp(App):

    def build(self):
        sm = ScreenManager()
        sc1 = ScreenOne(name='screen1')
        sc2 = ScreenTwo(name='screen2')
        sm.add_widget(sc1)
        sm.add_widget(sc2)
        print (sm.screen_names)
        return sm


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

Answer 1

If you want your "kid" to act as a "parent" give him a chance to listen to the same "kwargs".

Feed super(). init () with **kwargs and it will work.