Kivy - 屏幕管理器 - 访问其他类中的属性

问题描述

使用 Kivy 屏幕管理器，我创建了两个屏幕.在屏幕 1 中，我想更改屏幕 2 中的标签.我在我的代码中突出显示有问题的区域:

Using the Kivy Screen Manager, I create two Screens. Whilst being in screen 1, i want to change a label in screen two. I highlight the problematic area in my code:

我的test.ky:

#: import ScreenManager kivy.uix.screenmanager.ScreenManager
#: import Screen kivy.uix.screenmanager.ScreenManager
#: import SettingsScreen screen


ScreenManager:
    MenuScreen:
    SettingsScreen:


<MenuScreen>:
    name: 'MenuScreen'
    BoxLayout:
        Button:
            text: 'Goto nn'
            on_press: 
                root.manager.current = 'SettingsScreen'
                root.change_text()


<SettingsScreen>:
    name: 'SettingsScreen'
    label_id: label_field
    BoxLayout:
        Label:
            id: label_field
            text: "to_be_changed"

还有我的 screen.py

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.screenmanager import ScreenManager, Screen


class MenuScreen(Screen):
    def change_text(self):
        pass
        # HERE: something like
        # root.SettingsScreen.label_field.text = 'new text'


class SettingsScreen(Screen):
    pass


class TestApp(App):
    pass

TestApp().run()

非常感谢任何帮助！谢谢，尼科

Any help is greatly appreciated! Thanks, Nico

推荐答案

这个怎么样:

当您按下 MenuScreen 上的按钮时，它会在自身上设置一个属性，其中包含您要放在 SettingsScreen 标签中的文本.然后在kv文件中给MenuScreen分配一个id值，用来引用这个属性.示例:

When you press the button on MenuScreen, it sets an attribute on itself containing the text you want to put in the SettingsScreen Label. Then the MenuScreen is assigned an id value in the kv file, which is used to reference this attribute. Example:

ma​​in.py

class MenuScreen(Screen):
    text = StringProperty('')
    def change_text(self):
        self.text = "The text you want to set"
        self.manager.current = "SettingsScreen"

class SettingsScreen(Screen):
    label_text = StringProperty('')

kv 文件

ScreenManager:
    id: screen_manager
    MenuScreen:
        id: menu_screen
        name: 'MenuScreen'
        manager: screen_manager
    SettingsScreen:
        name: 'SettingsScreen'
        manager: screen_manager
        label_text: menu_screen.text

<MenuScreen>:
    BoxLayout:
        Button:
            text: 'Goto nn'
            on_press:
                root.change_text()

<SettingsScreen>:
    BoxLayout:
        Label:
            text: root.label_text

如您所见，我在 kv 文件中的 ScreenManager 下设置了屏幕的名称和 id，因为这是我通常会做的事情.

As you can see, I set the names and id of the screens under ScreenManager itself in the kv file, as this is what I would usually do to make this work.

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