如何更改 kivy 中另一个 class 的标签？

Question

我的应用程序有 2 个 windows。第二个 window 有一个标签，我想用第一个 window 按钮更改它的文本。但每次我得到同样的错误：

AttributeError: 'super' object has no attribute '__getattr__'

这是我的 Python 代码：

from kivy.lang.builder import Builder
from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen

class WindowManager(ScreenManager):
    pass

class FirstWindow(Screen):
    def change_label(self):
        self.parent.ids.label_id.text = 'label is changed'
        
class SecondWindow(Screen):
    pass

Builder.load_file('new.kv') 

class FirstApp(App): 
    def build(self):
        screen_manager = ScreenManager()
        screen_manager.add_widget(FirstWindow(name = 'first'))
        screen_manager.add_widget(SecondWindow(name = 'second'))
        return screen_manager

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

和我的 .kv 文件：

#:kivy 2.0.0

<FirstWindow>:
    name: "first"
    padding: 50
    spacing: 250

    BoxLayout:
        padding: 50
        spacing: 250
        orientation: 'vertical'  

        Button:
            text: 'change_label'
            pos_hint: {'center_x': 0.5, 'center_y': 0.15}
            on_release:
                root.change_label()
        
        Button:
            text: 'second window'
            pos_hint: {'center_x': 0.5, 'center_y': 0.15}
            on_release:
                root.manager.current = 'second'
                root.manager.transition.direction = 'left'
         
<SecondWindow>:
    name: 'second' 
    padding: 50
    spacing: 250
    label_id: label_id
   
    BoxLayout:
        padding: 50
        spacing: 50
        orientation: 'vertical'   

        Label:
            id: label_id
            text: 'this label'
   
        Button:
            text: 'first window'  
            on_release:
                app.root.current = "first" 
                root.manager.transition.direction = 'right'

Answer 1

您只需要获取对 SecondWindow 实例的引用，您可以使用 ScreenManager:

的 get_screen() 方法来实现

class FirstWindow(Screen):
    def change_label(self):
        # self.parent.ids.label_id.text = 'label is changed'
        self.manager.get_screen('second').ids.label_id.text = 'label is changed'

如何更改 kivy 中另一个 class 的标签？

How to change label from another class in kivy?

python

kivy

kivy-language