Calculator using PySimpleGUI – Python

Last Updated : 24 Feb, 2021

PySimpleGUI is a Python package that enables Python programmers of all levels to create GUIs. You specify your GUI window using a “layout” that contains widgets (they’re called “Elements” in PySimpleGUI). In this article, we will learn, how to make a calculator using PySimpleGUI in Python.

Before starting we need to install this package:

pip install PySimpleGUI

Approach:

Import the PySimpleGUI Module
Create GUI layout and Window
Add any number of widgets to the main window
Apply the event Trigger on the widgets.

Below is what the GUI looks like:

Let’s create a GUI-based simple calculator using the Python PySimpleGUI module, which can perform basic arithmetic operation’s addition, subtraction, multiplication, and division.

Let’s Understand step by step implementation:-

Step1: Create Text Box, Buttons

For creating a text box, we will use Txt() method.

Syntax: Txt(Enter Text, *attr)

Here will use the read button using ReadFormButton() method.

Syntax: ReadFormButton(Enter Button Text, *attr)

Step 2: Create an infinite loop, read the button value and perform the operation.

Python3

# Result Value 
Result = '' 
  
# Make Infinite Loop 
while True: 
    # Button Values 
    button, value = form.Read() 
      
    # Check Press Button Values 
    if button=='c': 
        Result = '' 
        form.FindElement('input').Update(Result) 
    elif button=='«': 
        Result = Result[:-1] 
        form.FindElement('input').Update(Result) 
    elif len(Result) == 16 : 
        pass
      
   # Results 
    elif button=='=': 
        Answer = eval(Result) 
        Answer = str(round(float(Answer),3)) 
        form.FindElement('input').Update(Answer) 
        Result = Answer 
    # close the window 
    elif button=='Quit'  or button==None: 
        break
    else: 
        Result += button 
        form.FindElement('input').Update(Result)

Below is the full implementation :

Python3

# Import Module 
from PySimpleGUI import *
  
# GUI Layout 
layout = [[Txt(''  * 10)], 
          [Text('', size = (15, 1), font = ('Helvetica', 18), 
                text_color = 'black', key = 'input')], 
          [Txt(''  * 10)], 
          [ReadFormButton('c'), ReadFormButton('«')], 
          [ReadFormButton('7'), ReadFormButton('8'), ReadFormButton('9'), ReadFormButton('/')], 
          [ReadFormButton('4'), ReadFormButton('5'), ReadFormButton('6'), ReadFormButton('*')], 
          [ReadFormButton('1'), ReadFormButton('2'), ReadFormButton('3'), ReadFormButton('-')], 
          [ReadFormButton('.'), ReadFormButton('0'), ReadFormButton('='), ReadFormButton('+')], 
          ] 
  
# Set PySimpleGUI 
form = FlexForm('CALCULATOR', default_button_element_size = (5, 2), 
                auto_size_buttons = False, grab_anywhere = False) 
form.Layout(layout) 
  
# Result Value 
Result = '' 
  
# Make Infinite Loop 
while True: 
    # Button Values 
    button, value = form.Read() 
      
    # Check Press Button Values 
    if button == 'c': 
        Result = '' 
        form.FindElement('input').Update(Result) 
    elif button=='«': 
        Result = Result[:-1] 
        form.FindElement('input').Update(Result) 
    elif len(Result) == 16 : 
        pass
      
   # Results 
    elif button == '=': 
        Answer = eval(Result) 
        Answer = str(round(float(Answer),3)) 
        form.FindElement('input').Update(Answer) 
        Result = Answer 
          
    # close the window 
    elif button == 'Quit'  or button == None: 
        break
    else: 
        Result += button 
        form.FindElement('input').Update(Result)