在单独的 .kv (Kivy) 文件中定义的屏幕之间切换 [英] Switching between screens defined in separate .kv (Kivy) files

问题描述

我曾经通过在单个 .kv 文件中定义所有内容(包括屏幕)，设法使多屏幕程序工作.

通过使用 root.current(在 .kv 文件中)或 self.root.current(在 Python 文件中)，我能够在屏幕之间切换.但是，一旦有多个带有许多小部件的屏幕，.kv 文件就会变得非常大且难以维护.

这次我尝试在单独的 .kv 文件中定义屏幕，但我无法在屏幕之间切换工作.到目前为止，每次尝试都会导致错误(语法无效，未定义屏幕名称...).

是否有一种(或多种)方法可以在不同的 .kv 文件中定义的屏幕之间切换?这是我正在使用的文件:

ma​​in.py

from kivy.app import App类 MainApp(App):经过如果 __name__ == '__main__':MainApp().run()

ma​​in.kv:

#:include screen_1.kv#:include screen_2.kv#:import NoTransition kivy.uix.screenmanager.NoTransition屏幕管理器:过渡:NoTransition()屏幕:名称:主屏幕"框布局:方向:垂直"标签:文字:主屏幕"按钮:文本:到屏幕 1"on_press: app.root.current = "screen_1"按钮:文字:到屏幕 2"on_press: app.root.current = "screen_2"

screen_1.kv:

屏幕:名称:'screen_1'框布局:方向:垂直"标签:文本:屏幕 1"按钮:文字:到主屏幕"on_press: app.root.current = "main_screen"按钮:文字:到屏幕 2"on_press: app.root.current = "screen_2"

screen_2.kv:

屏幕:名称:'screen_2'框布局:方向:垂直"标签:文本:屏幕 2"按钮:文字:到主屏幕"on_press: app.root.current = "main_screen"按钮:文本:到屏幕 1"on_press: app.root.current = "screen_1"

解决方案

解决方案

1. 将

   I once managed to get a multi-screen program working by having everything (including screens) defined in a single .kv file.

   By using root.current (in .kv file) or self.root.current (in Python file) I was able to switch between screens. However, the .kv file grows very large and hard to maintain once there are several screens with many widgets.

   This time I tried to define Screens in separate .kv files, but I can't get switching between screens to work. Every attempt so far resulted in an error (invalid syntax, screen name not defined...).

   Is there a way (or ways) to switch between screens, defined in separate .kv files? Here are the files I am using:

   main.py

   from kivy.app import App
   
   
   class MainApp(App):
       pass
   
   
   if __name__ == '__main__':
       MainApp().run()
   

   main.kv:

   #:include screen_1.kv
   #:include screen_2.kv
   
   #:import NoTransition kivy.uix.screenmanager.NoTransition
   
   ScreenManager:
       transition: NoTransition()
   
   
       Screen:
           name: "main_screen"
   
           BoxLayout:
               orientation: "vertical"
   
               Label:
                   text: "main screen"
               Button:
                   text: "to screen 1"
                   on_press: app.root.current = "screen_1"
               Button:
                   text: "to screen 2"
                   on_press: app.root.current = "screen_2"
   

   screen_1.kv:

   Screen:
       name: 'screen_1'
   
       BoxLayout:
           orientation: "vertical"
   
           Label:
               text: "Screen 1"
           Button:
               text: "to main screen"
               on_press: app.root.current = "main_screen"
           Button:
               text: "to screen 2"
               on_press: app.root.current = "screen_2"
   

   screen_2.kv:

   Screen:
       name: 'screen_2'
   
       BoxLayout:
           orientation: "vertical"
   
           Label:
               text: "Screen 2"
           Button:
               text: "to main screen"
               on_press: app.root.current = "main_screen"
           Button:
               text: "to screen 1"
               on_press: app.root.current = "screen_1"
   

   解决方案

   Solution

   1. Add dynamic class into screen_1.kv and screen_2.kv, e.g. <Screen1@Screen>: and <Screen2@Screen>: respectively.
   2. Instantiate screens, Screen1: and Screen2: in main.kv

   Example

   screen_1.kv

   <Screen1@Screen>:
       name: 'screen_1'
   
       BoxLayout:
           orientation: "vertical"
   
           Label:
               text: "Screen 1"
           Button:
               text: "to main screen"
               on_press: app.root.current = "main_screen"
           Button:
               text: "to screen 2"
               on_press: app.root.current = "screen_2"
   

   screen_2.kv

   <Screen2@Screen>:
       name: 'screen_2'
   
       BoxLayout:
           orientation: "vertical"
   
           Label:
               text: "Screen 2"
           Button:
               text: "to main screen"
               on_press: app.root.current = "main_screen"
           Button:
               text: "to screen 1"
               on_press: app.root.current = "screen_1"
   

   main.kv

   #:include screen_1.kv
   #:include screen_2.kv
   
   #:import NoTransition kivy.uix.screenmanager.NoTransition
   
   
   ScreenManager:
       transition: NoTransition()
   
   
       Screen:
           name: "main_screen"
   
           BoxLayout:
               orientation: "vertical"
   
               Label:
                   text: "main screen"
               Button:
                   text: "to screen 1"
                   on_press: app.root.current = "screen_1"
               Button:
                   text: "to screen 2"
                   on_press: app.root.current = "screen_2"
   
       Screen1:
   
       Screen2:
   

   Output

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