Python kivy 两个 GridLayout 和 Screen Manager

Question

我在 kivy 中有两个应用程序。 两者都基于 GridLayout 发现了一个类似的问题但是没看懂：Associating Screens with GridLayout classes in kivy

在.py中：

import kivy
kivy.require("1.9.0")
from kivy.uix.label import Label
from kivy.properties import ObjectProperty
from kivy.app import App
from kivy.uix.gridlayout import GridLayout

class FirstScreen(GridLayout):
    #some methods
class SecondScreen(GridLayout):
    #some methods

在.kv

中

<FirstScreen>:
    id: sterowanie_serv
    display: entry
    rows: 10
    padding: 10
    spacing: 10
    BoxLayout:
        spacing: 20
        CustButton:
            text:'1'
            on_press: do method from second screen class
        CustButton:
            text:'x'
            on_press: do method from second screen class
        CustButton:
            text:'go to Second screen'
            on_press: root.manager.current = 'SecondScreen'

<SecondScreen>:
    id: Przemo
    display: entry
    rows: 5
    padding: 10
    spacing: 10
    BoxLayout:
        spacing: 20
        CustButton:
            text:'1'
            on_press: do method from second screen class
        CustButton:
            text:'x2'
            on_press: do method from second screen class
        CustButton:
            text:'go to First screen'
            on_press: root.manager.current = 'SecondScreen'

如何使用屏幕管理器先显示First Screen并点击按钮Second Screen显示？

在按钮将是：

on_press: 
    root.manager.current = 'SecondScreen'

Answer 1

ScreenManager 仅接受 Screen 小部件。 FirstScreen 和 SecondScreen 必须是 Screen 实例，它们不能是 GridLayouts。在 FirstScreen 和 SecondScreen 内部是您应该创建 GridLayouts 的地方。

另一方面，ScreenManager.current 属性是当前显示的屏幕的名称。您需要在您的窗口中设置 name 属性。

基于您的代码的示例：

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen

kv_text = """\
#:import WipeTransition kivy.uix.screenmanager.WipeTransition
<MainScreen>:
    transition: WipeTransition()
    id: sm
    FirstScreen:
    SecondScreen:

<FirstScreen>:
    name: "first_screen"
    GridLayout:
        id: sterowanie_serv
        rows: 10
        padding: 10
        spacing: 10
        BoxLayout:
            spacing: 20
            Button:
                text:'1'
                on_press: print(app.root)
            Button:
                text:'x'
                on_press: print('Button X')
            Button:
                text:'go to Second screen'
                on_press: app.root.current = 'second_screen'

<SecondScreen>:
    name: "second_screen"
    GridLayout:
        id: Przemo
        rows: 5
        padding: 10
        spacing: 10
        BoxLayout:
            spacing: 20
            Button:
                text:'1'
                on_press: print('Button 1')
            Button:
                text:'x2'
                on_press: print('Button X2')
            Button:
                text:'go to First screen'
                on_press: app.root.current = 'first_screen'
"""

class MainScreen(ScreenManager):
    def __init__(self):
        super(MainScreen, self).__init__()

class FirstScreen(Screen):
    #some methods
    pass

class SecondScreen(Screen):
    #some methods
    pass

class MyKivyApp(App):
    def build(self):
        return MainScreen()

def main():
    Builder.load_string(kv_text)
    app = MyKivyApp()
    app.run()

if __name__ == '__main__':
    main()

运行示例：