CardTransition 在 Kivy 1.9.1 中不起作用

Question

我正在尝试在 kivy 中制作一个使用 CardTransition 的多屏幕简单应用程序，但是当我尝试 运行 它时，我得到了一个错误。我知道该应用程序本身可以正常工作，因为我已经尝试过不同的过渡并且它运行良好。我正在使用 Python 3.4.4 和 Kivy 1.9.1。

代码如下：

import kivy
kivy.require("1.9.1")

from kivy.uix.boxlayout     import BoxLayout
from kivy.app               import App
from kivy.uix.label         import Label
from kivy.uix.button        import Button
from kivy.lang              import Builder
from kivy.uix.screenmanager import ScreenManager, Screen, SwapTransition, CardTransition

KivyFile = Builder.load_string("""
<Screen1>:
    name: "Screen1"
    BoxLayout:
        orientation: "vertical"
        padding: 40
        spacing: 20

        Label:
            text: "This is screen 1"
        Button:
            text: "Next Screen"
            on_release: app.root.current = "Screen2"
<Screen2>:
    name: "Screen2"
    BoxLayout:
        orientation: "vertical"
        padding: 40
        spacing: 20

        Label:
            text: "This is screen 2"
        Button:
            text: "Next Screen"
            on_release: app.root.current = "Screen3"
<Screen3>:
    name: "Screen3"
    BoxLayout:
        orientation: "vertical"
        padding: 40
        spacing: 20

        Label:
            text: "This is screen 3"
        Button:
            text: "Next Screen"
            on_release: app.root.current = "Screen1"
""")

class Screen1(Screen):
    pass

class Screen2(Screen):
    pass

class Screen3(Screen):
    pass

sm = ScreenManager(transition=CardTransition())
sm.add_widget(Screen1(name = "Screen1"))
sm.add_widget(Screen2(name = "Screen2"))
sm.add_widget(Screen3(name = "Screen3"))

class MyApp(App):

    def build(self):
        return sm

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

这是我得到的错误：

 Traceback (most recent call last):
   File "C:/Users/Markus/Desktop/Kivy/TestTransitions.py", line 9, in <module>
     from kivy.uix.screenmanager import ScreenManager, Screen, SwapTransition, CardTransition
 ImportError: cannot import name 'CardTransition'

Answer 1

CardTransition 仅在 kivy 1.10 中添加。