我需要在.kv文件中隐藏声明的对象

# Python 代码中定义一个自定义的Widget
from kivy.uix.widget import Widget

class HiddenWidget(Widget):
    pass

# 在.kv文件中使用这个自定义的Widget
<HiddenWidget>:
    canvas:
        Color:
            rgba: 1, 1, 1, 0  # 设置opacity为0
        Rectangle:
            pos: self.pos
            size: self.size

# 在.kv文件中直接设置size_hint
<SomeWidget>:
    BoxLayout:
        size_hint_y: None
        height: '48dp'
        Button:
            text: 'Visible Button'
        Button:
            text: 'Hidden Button'
            size_hint: (0, 0)  # 设置size_hint为(0, 0)

# main.py
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout

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

class MyLayout(BoxLayout):
    pass

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

# my.kv
<MyLayout>:
    orientation: 'vertical'
    Button:
        text: 'Visible Button'
    Button:
        text: 'Hidden Button'
        opacity: 0  # 或者 size_hint: (0, 0)