在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()

和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:

控制kv和python小部件很简单（但是我不知道如何在kv文件中更容易编写小部件等，但仍然需要在python中创建一些用于自动内容）或者更好的只是在python中创建所有的kv文件？我想做这样的事情：总是显示左侧菜单的应用程序，右侧另一个基于屏幕的动态内容屏幕（从菜单中点击）可能是另一个简单的解决方案。有人可以一步一步解释我吗？ ：）

Answer 1

AttributeError的

AttributeError的解决方案，请在test.kv文件中将“id：'test'”替换为“id：test”。

动态内容

可以根据菜单中的点击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）。如果不删除小部件，每次进入屏幕时都会添加每个小部件的重复/倍数（TestScreen / SettingsScreen）。我建议使用on_pre_enter和on_leave方法。有关详细信息，请参阅以下示例。

实施例

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