盒子布局中嵌套布局

# 布局类名不要写错这个是大坑
<BoxLayoutWidget>:    
    orientation:'vertical' # 纵向
    canvas:
        Color:
            rgba:[1,1,1,1]
        Rectangle:
            size:self.size
            pos: self.pos
    Button:
        text:'hello'

    Buton:
        text:"hello2"

    BoxLayout:
    # 盒子布局中嵌套布局 设为横向
        orientation:'horizontal'
        Button:
            text:"hell03"
            size_hint_y:.2

        Button:
            text:'hello4'
            size_hint_y:.3