如何在Kivy界面中显示变量文本

from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout

class MyBoxLayout(BoxLayout):
    def __init__(self, **kwargs):
        super(MyBoxLayout, self).__init__(**kwargs)
        self.orientation = 'vertical'
        self.label = Label(text='初始文本')
        self.add_widget(self.label)

class MyApp(App):
    def build(self):
        return MyBoxLayout()

from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout

class MyBoxLayout(BoxLayout):
    def __init__(self, **kwargs):
        super(MyBoxLayout, self).__init__(**kwargs)
        self.orientation = 'vertical'
        self.label = Label(text='初始文本')
        self.add_widget(self.label)

        # 模拟更新文本的操作
        self.update_text()

    def update_text(self):
        # 更新Label控件的文本
        self.label.text = '变量文本'

class MyApp(App):
    def build(self):
        return MyBoxLayout()

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