Kivy - 如何在不同的屏幕中更改屏幕转换

Question

我有两个屏幕.当我按下"下一个屏幕"按钮时,它将转到第二个屏幕,转换应该是SlideTransition(左),当我按下'后退'按钮时,它应该返回到第一个屏幕,转换应该是SlideTransition(右) ).

怎么做？它只在我的代码中使用1个转换

这是我的代码py/kv代码:

class 1stScreen(Screen):
    ...some methods...

class 2ndScreen(Screen):
    ...some methods...

class MyScreenManager(ScreenManager):
    pass

root_widget = Builder.load_string('''
#:import SlideTransition kivy.uix.screenmanager.SlideTransition

MyScreenManager:
    transition: SlideTransition(direction='left')
    1stScreen:

    transition: SlideTransition(direction='right') #<-- Im getting error with this
    2ndScreen:

<1stScreen>:
     name: '1stScreen'
     ...some widgets...
     Button:
         text: 'next screen'
         on_release: app.root.current = '2ndScreen'

<2ndScreen>:
     name: '2ndScreen'
     ...some widgets...
     Button:
         text: 'back'
         on_release: app.root.current = '1stScreen'
''')

class Main(App):
    def build(self):
        return root_widget

if __name__ == "__main__":
    Main().run()

Answer 1

将转换放在on_release事件中.

Button:
    text: 'next screen'
    on_release:
        app.root.transition = SlideTransition(direction='right')
        app.root.current = '2ndScreen'
...