python - Kivy 不使用操作栏上的按钮更改屏幕

Question

我提到的代码来自 ikolim 的回答：为什么我的 Kivy Actionbar 不见了？

这是我的python代码：

from kivy.app import App
from kivy.uix.screenmanager import ScreenManager,Screen
from kivy.properties import ObjectProperty
from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
from kivy.core.window import Window

Window.clearcolor = (1,1,1,1)

Builder.load_file("designdawkalamomarunong.kv")


class Menu(BoxLayout):
    manager = ObjectProperty(None)

class Add(Screen):
    pass

class Help(Screen):
    pass

class Credits(Screen):
    pass

class Manager(ScreenManager):
    addScreen = ObjectProperty(None)
    helpScreen = ObjectProperty(None)
    creditsScreen = ObjectProperty(None)

class AntsApp(App):

    def build(self):
        return Menu()


if __name__ == '__main__':
    AntsApp().run()

这是基维代码：

<Menu>:
    manager: screen_manager
    orientation: "vertical"
    ActionBar:
        size_hint_y: 0.1
        ActionView:
            ActionPrevious:
            ActionButton:
                text: "Add"
                on_release: app.root.current = "add"
            ActionButton:
                text:"Help"
                on_release: app.root.current = "help"
            ActionButton:
                text: "Credits"
                on_release: app.root.current = "credits"
    Manager:
        id: screen_manager

<Add>:
    text: "hello boi"

<Help>:
    text: "hello world"

<Credits>:
    text: "goodbye world lol"

<Manager>:
    id: screen_manager
    addScreen: addScreen
    helpScreen: helpScreen
     creditsScreen: creditsScreen

    Add:
        id: addScreen
        name: 'add'
        manager: screen_manager

    Help:
        id: helpScreen
        name: 'help'
        manager: screen_manager

    Credits:
        id: creditsScreen
        name: 'credits'
        manager: screen_manager

当我运行它时，这是输出：

当我单击操作栏上的按钮时，它不会返回任何内容。我应该添加其他东西吗？先感谢您 ：）

编辑：尝试这样做：

<Add>:
    Button:
        text: "hello boi"

它有效但是当我尝试这个时：

<Add>:
    Label:
        text: "hello boi"

那没起效。我在这里想念什么？

标签： pythonpython-3.xkivykivy-language

Answer 1

问题

.kv 文件

1. 替换所有出现的app.root.current因为root.manager.current是root小BoxLayout部件而不是ScreenManager小部件。
2. 每个屏幕Label在text.
3. 当您在 Screen 的每个类规则中将 Button 小部件实例化为子项时，文本是可见的。但是，当您将 Button 小部件替换为 Label 时，文本是不可见的。原因是因为 Label 的默认颜色文本是白色 ( rgba=1, 1, 1, 1)，而 BoxLayout 的颜色也是白色。因此，您无法看到文本。如果使用标签小部件，请添加color: (0, 0, 0, 1) # black color text.

例子

.kv 文件

#:kivy 1.11.0

<Menu>:
    manager: screen_manager
    orientation: "vertical"
    ActionBar:
        size_hint_y: 0.1
        ActionView:
            ActionPrevious:
            ActionButton:
                text: "Add"
                on_release: root.manager.current = "add"
            ActionButton:
                text:"Help"
                on_release: root.manager.current = "help"
            ActionButton:
                text: "Credits"
                on_release: root.manager.current = "credits"
    Manager:
        id: screen_manager

<Add>:
    Label:
        text: "hello boi"
        color: 0, 0, 0, 1   # black color text

<Help>:
    Label:
        text: "hello world"
        color: 0, 0, 0, 1   # black color text

<Credits>:
    Label:
        text: "goodbye world lol"
        color: 0, 0, 0, 1   # black color text

<Manager>:
    addScreen: addScreen
    helpScreen: helpScreen
    creditsScreen: creditsScreen

    Add:
        id: addScreen
        name: 'add'

    Help:
        id: helpScreen
        name: 'help'

    Credits:
        id: creditsScreen
        name: 'credits'

输出