python中的kivy小部件到kv文件，如何控制它

Question

我有一个简单的测试程序：

main.py

from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.screenmanager import Screen
from kivy.clock import mainthread


class TestScreen(Screen):
@mainthread
def on_pre_enter(self): #Is loaded before kv buttons etc? how make it work
   pass
@mainthread
def on_enter(self): #Load after kv buttons etc?
    button = Button(text="Work?")
    #how now add it to display?
    #how control where display it? on end or begin is just about on_pre and on?

class TestApp(App):
    pass

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

还有test.kv文件

#:import NoTransition kivy.uix.screenmanager.NoTransition 
<TestScreen>:   
    name:'try'
    GridLayout:
        id:'test'
        cols:2
        Button:
            text:'Test'
            on_press:app.root.current='Main'
ScreenManager:
    transition: NoTransition()
    Screen:
        name: 'Main'
        GridLayout:
            cols:1
            Button:
                text:'1'                
            Button:
                text:'2'
            Button:
                text:'Test'
                on_press:root.current='try'
    TestScreen:

很容易控制 kv 和 python 小部件（但我不知道如何在 kv 文件中编写小部件等更容易，但仍然需要在 python 中创建一些用于自动内容）或者更好的是在没有 kv 文件的情况下在 python 中创建所有?我想做这样的事情：始终显示左侧菜单的应用程序，而在右侧另一个具有基于屏幕的动态内容的屏幕（从菜单中单击）可能是另一个简单的解决方案。任何人都可以逐步解释我吗？ :)

Answer 1

属性错误

AttributeError的解决方法，请将test.kv文件中的“id:'test'”替换为“id:test”。

动态内容

可以根据从菜单中单击来显示具有动态内容的屏幕。但请记住删除退出屏幕时添加的小部件（TestScreen/SettingsScreen）。如果您不删除小部件，则每次进入屏幕（TestScreen/SettingsScreen）时，您将获得每个添加的小部件的副本/倍数。我建议使用 on_pre_enter 和 on_leave 方法。详情请参考以下示例。

示例

main.py

​​>

from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.button import Button


class MyScreenManager(ScreenManager):
    pass


class MenuScreen(Screen):
    pass


class SettingsScreen(Screen):
    def on_pre_enter(self, *args):
        self.ids.test.add_widget(Button(text="Work?"))

    def on_leave(self, *args):
        self.ids.test.remove_widget(self.ids.test.children[0])


class TestApp(App):
    title = "Add & Remove Widgets Dynamically"

    def build(self):
        return MyScreenManager()


if __name__ == "__main__":
    TestApp().run()

test.kv

#:kivy 1.10.0
#:import NoTransition kivy.uix.screenmanager.NoTransition

<MyScreenManager>:
    transition: NoTransition()
    MenuScreen:
    SettingsScreen:

<MenuScreen>:
    name: 'menu'
    GridLayout:
        cols: 1
        Button:
            text: '1'
        Button:
            text: '2'
        Button:
            text: 'Test'
            on_press: root.manager.current = 'settings'

<SettingsScreen>:
    name:'settings'
    GridLayout:
        id: test
        cols: 2
        Button:
            text: 'Test'
            on_press: root.manager.current = 'menu'

输出