Python|没有 .kv 文件的 Kivy 中的网格布局

Kivy 是一个独立于平台的平台，可以在 Android、IOS、linux 和 Windows 等平台上运行。Kivy 为您提供了一次编写代码并在不同平台上运行的功能。基本上是用来开发Android应用的，但不代表不能用在Desktops应用上。

???????? Kivy Tutorial – Learn Kivy with Examples.

网格布局：

• 小部件必须放置在特定的列/行中。每个孩子都会自动分配一个位置，该位置由布局配置和孩子在孩子列表中的索引决定。
• 网格布局必须始终包含以下任一输入约束：
  GridLayout.cols 或 GridLayout.rows。如果不指定 cols 或 rows，则 Layout 将抛出异常。
• GridLayout 将子元素排列在矩阵中。它占用可用空间并将其划分为列和行，然后将小部件添加到生成的“单元格”。
• 行和列就像我们在矩阵中观察到的一样，在这里我们可以调整每个网格的大小。
• 初始大小由 col_default_width 和 row_default_height 属性给出。我们可以通过设置 col_force_default 或 row_force_default 属性来强制使用默认大小。这将强制布局忽略子项的 width 和 size_hint 属性并使用默认大小。

要使用 GridLayout，我们需要做的第一件事就是导入它。

from kivy.uix.gridlayout import GridLayout 

创建 GridLayout 的基本方法：

1) import kivy
2) import kivyApp
3) import button
4) import Gridlayout
5) Set minimum version(optional)
6) create App class:
          - define build function
              : add widget (Buttons)
7) return Layout/widget/Class(according to requirement)
8) Run an instance of the class

方法的实施——
代码#1：
在下面的示例中，所有小部件都将具有相同的大小。默认情况下，size_hint 为 (1, 1)，因此 Widget 将采用父级的完整大小：

Python3

# Sample Python application demonstrating 
# How to create GridLayout in Kivy
 
# import kivy module
import kivy
   
# base Class of your App inherits from the App class.  
# app:always refers to the instance of your application  
from kivy.app import App
   
# creates the button in kivy 
# if not imported shows the error 
from kivy.uix.button import Button
 
# The GridLayout arranges children in a matrix.
# It takes the available space and
# divides it into columns and rows,
# then adds widgets to the resulting “cells”.
from kivy.uix.gridlayout import GridLayout
 
# creating the App class
class Grid_LayoutApp(App):
 
    # to build the application we have to
    # return a widget on the build() function.
    def build(self):
 
        # adding GridLayouts in App
        # Defining number of column
        # You can use row as well depends on need
        layout = GridLayout(cols = 2)
 
        # 1st row
        layout.add_widget(Button(text ='Hello 1'))
        layout.add_widget(Button(text ='World 1'))
 
        # 2nd row
        layout.add_widget(Button(text ='Hello 2'))
        layout.add_widget(Button(text ='World 2'))
 
        # 3rd row
        layout.add_widget(Button(text ='Hello 3'))
        layout.add_widget(Button(text ='World 3'))
 
        # 4th row
        layout.add_widget(Button(text ='Hello 4'))
        layout.add_widget(Button(text ='World 4'))
 
        # returning the layout
        return layout
 
# creating object of the App class
root = Grid_LayoutApp()
# run the App
root.run()

输出：

现在只需用代码#2 和代码#3 更改上面代码中的类代码，除此之外，所有代码都将与代码#1 相同，并在更改后运行代码，您将得到以下结果。
代码#2：
现在，让我们将 Hello 按钮的大小固定为 100px，而不是使用 size_hint_x=1：

Python3

# creating the App class
class Grid_LayoutApp(App):
 
    # to build the application we have to
    # return a widget on the build() function.
    def build(self):
 
        # adding GridLayouts in App
        # Defining number of column
        # You can use row as well depends on need
        layout = GridLayout(cols = 2)
 
        # 1st row
        layout.add_widget(Button(text ='Hello 1', size_hint_x = None, width = 100))
        layout.add_widget(Button(text ='World 1'))
 
        # 2nd row
        layout.add_widget(Button(text ='Hello 2', size_hint_x = None, width = 100))
        layout.add_widget(Button(text ='World 2'))
 
        # 3rd row
        layout.add_widget(Button(text ='Hello 3', size_hint_x = None, width = 100))
        layout.add_widget(Button(text ='World 3'))
 
        # 4th row
        layout.add_widget(Button(text ='Hello 4', size_hint_x = None, width = 100))
        layout.add_widget(Button(text ='World 4'))
 
        # returning the layout
        return layout

输出：

代码#3：
现在，让我们将行高固定为特定大小：

Python3

# creating the App class
class Grid_LayoutApp(App):
 
    # to build the application we have to
    # return a widget on the build() function.
    def build(self):
 
        # adding GridLayouts in App
        # Defining number of column and size of the buttons i.e height
        layout = GridLayout(cols = 2, row_force_default = True,
                            row_default_height = 30)
 
        # 1st row
        layout.add_widget(Button(text ='Hello 1', size_hint_x = None, width = 100))
        layout.add_widget(Button(text ='World 1'))
 
        # 2nd row
        layout.add_widget(Button(text ='Hello 2', size_hint_x = None, width = 100))
        layout.add_widget(Button(text ='World 2'))
 
        # 3rd row
        layout.add_widget(Button(text ='Hello 3', size_hint_x = None, width = 100))
        layout.add_widget(Button(text ='World 3'))
 
        # 4th row
        layout.add_widget(Button(text ='Hello 4', size_hint_x = None, width = 100))
        layout.add_widget(Button(text ='World 4'))
 
        # returning the layout
        return layout

输出：

参考： https://kivy.org/doc/stable/api-kivy.uix.gridlayout.html