Kivy ScreenManager 切换屏幕离开按钮

Question

我正在使用 ScreenManager 来切换屏幕，但是当我正常切换屏幕时，屏幕上的按钮会保持不变。我必须将按钮复制到每个屏幕。有没有办法在保留按钮的同时切换屏幕？

这是我的应用程序代码：

import (...)


class AppContainer(FloatLayout):
    pass


class NavButtons(BoxLayout):
    pass


class FirstScreen(Screen):
    pass


class SecondScreen(Screen):
    pass


class Screens(ScreenManager):
    pass


class MainApp(App):
    def build(self):
        return AppContainer()

(...)

kv 文件如下所示：

#:import BoxLayout kivy.uix.boxlayout.BoxLayout

<AppContainer>:
    NavButtons:
    Screens:
        FirstScreen:
        SecondScreen:
        ThirdScreen:


<NavButtons>:
    orientation:'vertical'
    Button:
        on_press: root.manager.current="first"
        text: 'First'
        pos_hint:{"top": 1, "left": 0}
    Button:
        on_press: root.manager.current="second"
        text: 'Second'
        pos_hint:{"top":0.8, "left": 0}
<Button>:
    size_hint: 0.2, 0.2


<FirstScreen>:
    name: "first"
    Label:
        text: "First Screen"


<SecondScreen>:
    name: "second"
    Label:
        text: "Second Screen"

但这会引发错误：AttributeError: 'NavButtons' object has no attribute 'manager'

有什么想法吗？

Answer 1

在按钮的字段中，根是 NavButtons，如您所见，NavButtons 没有屏幕作为 children，一种访问方式 Screens 是通过 app.root 即 returns 在这种情况下到 AppContainer，我们将其设置为 Screens 我们访问它是因为他是 children.

#:import BoxLayout kivy.uix.boxlayout.BoxLayout

<AppContainer>:
    NavButtons:
    Screens:
        id: sm
        FirstScreen:
        SecondScreen:

<NavButtons>:
    orientation:'vertical'
    Button:
        on_press: app.root.ids.sm.current="first"
        text: 'First'
        pos_hint:{"top": 1, "left": 0}
    Button:
        on_press: app.root.ids.sm.current ="second"
        text: 'Second'
        pos_hint:{"top":0.8, "left": 0}

[...]

Kivy ScreenManager 切换屏幕离开按钮

Kivy ScreenManager switch screens leaving buttons

python

kivy

kivy-language