Python如何在Kivy中切换小部件（） _Kivy

Kivy是Python中与平台无关的GUI工具。由于它可以在Android, IOS, Linux和Windows等操作系统上运行。它基本上是用于开发Android应用程序, 但这并不意味着它不能在桌面应用程序上使用。

????Kivy教程–通过示例学习Kivy。

Switch小部件：
Switch小部件是活动的或不活动的, 作为机械灯开关。用户可以向左/向右滑动以激活/停用它。开关表示的值为True或False。那就是开关可以在On位置或关位置。
要使用Switch, 你必须导入：

from kivy.uix.switch import Switch

注意：如果要通过单次触摸而不是滑动来控制状态, 请改用ToggleButton。

Basic Approach:1) import kivy 2) import kivyApp 3) import Switch 4) import Gridlayout 5) import Label 6) Set minimum version(optional) 7) create Layout class(In this you create a switch) 8) create App class 9) return Layout/widget/Class(according to requirement) 10) Run an instance of the class

该方法的实施：

# Program to Show how to create a switch # 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# this restrict the kivy version i.e # below this kivy version you cannot # use the app or software kivy.require( '1.9.0' )# The Switch widget is active or inactive # The state transition of a switch is from # either on to off or off to on. from kivy.uix.switch import Switch# 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# The Label widget is for rendering text. from kivy.uix.label import Label# A Gridlayout with a label a switch # A class which contains all stuff about the switch class SimpleSwitch(GridLayout):# Defining __init__ constructor def __init__( self , * * kwargs):# super function can be used to gain access # to inherited methods from a parent or sibling class # that has been overwritten in a class object. super (SimpleSwitch, self ).__init__( * * kwargs)# no of coloumns self .cols = 2# Adding label to the Switch self .add_widget(Label(text = "Switch" ))# Initially switch is Off i.e active = False self .settings_sample = Switch(active = False )# Add widget self .add_widget( self .settings_sample)# Defining the App Class class SwitchApp(App): # define build function def build( self ): # retuen the switch class return SimpleSwitch()# Run the kivy app if __name__ = = '__main__' : SwitchApp().run()

输出如下：

文章图片

文章图片
将回调附加到交换机：

开关可以附加有回调, 以检索开关的值。
开关的状态转换是从ON到OFF或从OFF到ON。
当switch进行任何转换时, 将触发回调, 并且可以检索新状态(即传来新状态), 并且可以基于状态采取任何其他操作。
默认情况下, 小部件的表示形式是静态的。所需的最小尺寸为83 * 32像素。
整个窗口小部件都处于活动状态, 而不仅仅是带有图形的部分。只要你在小部件的边界框上滑动, 它就会起作用。

现在, 要附加回调, 你必须定义一个回调函数并将其与开关绑定。因此, 以下代码是如何附加回调的代码：

# Program to Show how to attach a callback to switch# 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# this restrict the kivy version i.e # below this kivy version you cannot # use the app or software kivy.require( '1.9.0' )# The Switch widget is active or inactive # The state transition of a switch is from # either on to off or off to on. from kivy.uix.switch import Switch# 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# The Label widget is for rendering text. from kivy.uix.label import Label# A Gridlayout with a label a switch # A class which contains all stuff about the switch class SimpleSwitch(GridLayout):# Defining __init__ constructor def __init__( self , * * kwargs):# super function can be used to gain access # to inherited methods from a parent or sibling class # that has been overwritten in a class object. super (SimpleSwitch, self ).__init__( * * kwargs)# no of coloumns self .cols = 2# Adding label to the Switch self .add_widget(Label(text = "Switch" ))# Initially switch is Off i.e active = False self .settings_sample = Switch(active = False )# Add widget self .add_widget( self .settings_sample)# Arranging a callback to the switch # using bing function self .settings_sample.bind(active = switch_callback)# Callback for the switch state transition # Defining a Callback function # Contains Two parameter switchObject, switchValue def switch_callback(switchObject, switchValue):# Switch value are True and False if (switchValue): print ( 'Switch is ON:):):)' ) else : print ( 'Switch is OFF:(:(:(' )# Defining the App Class class SwitchApp(App): # define build function def build( self ): # retuen the switch class return SimpleSwitch()# Run the kivy app if __name__ = = '__main__' : SwitchApp().run()

输出如下：