Python使用.kv文件的Kivy中的微调器小部件

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。

微调小部件：

要使用微调器, 你必须导入：

from kivy.uix.spinner import Spinner

Spinner是一个小部件, 提供了一种从一组中选择一个值的快速方法。在默认状态下, 微调器显示其当前选定的值。触摸微调器会显示一个下拉菜单, 其中包含所有其他可用值, 用户可以从中选择一个新值。

像组合框一样, 微调器对象可以具有多个值, 并且可以选择一个值。

回调可以附加到微调器对象上, 以接收有关从微调器对象选择值的通知。

Basic Approach:

1) import kivy
2) import kivyApp
3) import spinner
4) import Floatlayout(according to need)
5) import window(optional)
6) Set minimum version(optional)
7) Create Layout class:
      define the clicked function in it
8) Create App class
9) create .kv file (name same as the app class):
        1) create Spinner
        2) create callback
        3) And many more styling as needed
10) return Layout/widget/Class(according to requirement)
11) Run an instance of the class

下面是实现：

在下面的代码中, 我们创建了微调器, 并进行了大小调整和定位, 并将回调函数附加到值上。

.py文件：

# Sample spinner app in kivy using .kv file
  
# to change the kivy default settings we use this module config
from kivy.config import Config
  
# 0 being off 1 being on as in true /false
# you can use 0 or 1 && True or False
Config. set ( 'graphics' , 'resizable' , True )
  
# 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' )
  
# Spinner is a widget that provides a
# quick way to select one value from a set.
# like a dropdown list
from kivy.uix.spinner import Spinner
  
# module consists the floatlayout 
# to work with FloatLayout first 
# you have to import it 
from kivy.uix.floatlayout import FloatLayout
  
# Here for providing colour to the background
from kivy.core.window import Window
  
  
# create LayoutClass
class SampBoxLayout(FloatLayout):
     # For Spinner defining spinner clicked function
     def spinner_clicked( self , value):
         print ( "Language selected is " + value)
   
  
# # Make an App by deriving from the App class
class SampleApp(App):
     def build( self ):
   
         # Set the background color for the window
         Window.clearcolor = ( 0.555 , 0.261 , . 888 , 0.5 )
         return SampBoxLayout()
  
# create object for thje Appclass
root = SampleApp()
# run the class
root.run()

.kv文件

代码：

# .kv file implementation of the .py file
  
# Creating the Layout i.e root of the Layout class
<SampBoxLayout>:
  
     # creating the spinner
     Spinner:
         # Assigning id 
         id : spinner_id
  
         # Callback 
         on_text: root.spinner_clicked(spinner_id.text)
  
         # initially text on spinner
         text: "Python"
  
         # total values on spinner
         values: [ "Python" , "Java" , "C++" , "C" , "C#" , "PHP" ]
  
         # declaring size of the spinner
         # and the position of it
         size_hint: None , None
         size: 200 , 50
         pos_hint:{ 'center_x' :. 5 , 'top' : 1 }

输出如下：

图片1