Python如何使用Kivy制作计算器（） _Python设计计算器

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。

在本文中, 我们将学习如何使用Kivy创建一个简单的计算器。

先决条件：1)数学基础知识
2)Python
3)Kivy
4)小部件和代码对Kivy的理解

Basic approach to make A calculator:1) import kivy 2) import kivyApp 3) import Gridlayout 4) import config(to configure/adjust the window size) 5) Set minimum version(optional) 6) Create Layout class : define Calculator function in it : In this i am using try-catch because if any arithmetic exception occur it will through the error7) create App class 8) create .kv file (name same as the app class): 1) create buttons 2) Add the style to the buttons 3) Add fuctionalties of the button 9) return Layout/widget/Class(according to requirement) 10) Run an instance of the class

该方法的实施：
main.py

# Program to create a calculator # 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' ) # for making multiple bttons to arranging # them we are using this from kivy.uix.gridlayout import GridLayout# for the size of window from kivy.config import Config# Setting size to resizable Config. set ( 'graphics' , 'resizable' , 1 ) ## Config.set('graphics', 'width', '400') ## Config.set('graphics', 'height', '400')# Creating Layout class class CalcGridLayout(GridLayout):# Function called when equals is pressed def calculate( self , calculation): if calculation: try : # Solve formula and display it in entry # which is pointed at by display self .display.text = str ( eval (calculation)) except Exception: self .display.text = "Error"# Creating App class class CalculatorApp(App):def build( self ): return CalcGridLayout()# creating object and running it calcApp = CalculatorApp() calcApp.run()

计算器

# Custom button < CustButton@Button> : font_size: 32# Define id so I can refer to the CalcGridLayout # class functions # Display points to the entry widget < CalcGridLayout> : id : calculator display: entry rows: 6 padding: 10 spacing: 10# Where input is displayed BoxLayout: TextInput: id : entry font_size: 32 multiline: False# When buttons are pressed update the entry BoxLayout: spacing: 10 CustButton: text: "7" on_press: entry.text + = self .text CustButton: text: "8" on_press: entry.text + = self .text CustButton: text: "9" on_press: entry.text + = self .text CustButton: text: "+" on_press: entry.text + = self .textBoxLayout: spacing: 10 CustButton: text: "4" on_press: entry.text + = self .text CustButton: text: "5" on_press: entry.text + = self .text CustButton: text: "6" on_press: entry.text + = self .text CustButton: text: "-" on_press: entry.text + = self .textBoxLayout: spacing: 10 CustButton: text: "1" on_press: entry.text + = self .text CustButton: text: "2" on_press: entry.text + = self .text CustButton: text: "3" on_press: entry.text + = self .text CustButton: text: "*" on_press: entry.text + = self .text# When equals is pressed pass text in the entry # to the calculate function BoxLayout: spacing: 10 CustButton: text: "AC" on_press: entry.text = "" CustButton: text: "0" on_press: entry.text + = self .text CustButton: text: "=" on_press: calculator.calculate(entry.text) CustButton: text: "/" on_press: entry.text + = self .text BoxLayout: CustButton: font_size: 20 text: "Scientific calculator" on_press: entry.text = ""

输出如下：