６、StackLayout ，堆栈式布局方式

StackLayout的布局方式，其旨如下图：

1、默认的输出方式是从上到下，从左到右。

from kivy.app import App
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.uix.stacklayout import StackLayout
# from kivy.uix.gridlayout import GridLayout
from kivy.uix.widget import Widget
 
class StackLayoutExample(StackLayout):
    pass
# class GridLayoutExample(GridLayout):
#     pass
 
class AnchorLayoutExample(AnchorLayout):
    pass
class BoxLayoutExample(BoxLayout):
    pass
    #
    # def __init__(self,**kwargs):
    #     super().__init__(**kwargs)
    #     self.orientation="vertical"#y， else x
    #     a1=Button(text="aa")
    #     b1=Button(text="bb")
    #     c1 = Button(text="cc")
    #