How To Create Gui Python

Hey python developers, in Python Calculator tutorial you will learn to create a simple GUI calculator. In this post i will show you how to develop a simple calculator using tkinter module in python. So let's move further to create a simple python calculator.

Python offers a lot of options to develop GUI applications, but Tkinter is the most usable module for developing GUI(Graphical User Interface). Since Tkinter is cross-platform soit works on both windows and Linux. So here i am using Tkinter module to create a simple python calculator.

Python Calculator Tutorial – Getting Started With Tkinter

The fastest and easiest way of developing GUI applications in python is working with Tkinter. So let's took a quick look on Tkinter.

What is Tkinter

The Tkinter module ("Tk interface") is the standard Python interface to the Tk GUI toolkit.
Both Tk and Tkinter are available on most Unix platforms, as well as on Windows systems.
If you work on Linux/Ubuntu then you have to install Tkinter module on your machine for running programs, but on windows you don't need to install it because it comes with the default python installation.

Prerequisite For Python Calculator

For developing a simple GUI calculator in python you must have to prior knowledge of following –

Tkinter
Lambda

Look Of A Simple GUI Python Calculator

Look at this calculator. Yup this is looking very cool. So now we have to create this calculator in python.

On this calculator we can perform following simple mathematical calculations –

Multiplication
Addition
Subtraction
Division

And now we will start writing codes for making this. To create this we have to do four things –

Importing Tkinter module
Creating the main interface(window for calculator)
Adding any number of widgets to the main interface
Applying the event trigger on widgets

Creating Window For Calculator

First of all we will create a window of calculator. So write the following code.

from tkinter import *

# Creating frame for calculator

def iCalc ( source , side ) :

storeObj = Frame ( source , borderwidth=4 , bd=4 , bg="powder blue" )

storeObj . pack ( side=side , expand =YES , fill =BOTH )

return storeObj

# Creating Button

def button ( source , side , text , command=None ) :

storeObj = Button ( source , text=text , command=command )

storeObj . pack ( side=side , expand = YES , fill=BOTH )

return storeObj

class app ( Frame ) :

def __init__ ( self ) :

Frame . __init__ ( self )

self . option_add ( '*Font' , 'arial 20 bold' )

self . pack ( expand = YES , fill =BOTH )

self . master . title ( 'Calculator' )

# Start the GUI

if __name__=='__main__' :

app ( ) . mainloop ( )

Let's see the output.

We have created this frame successfully, now lets move on ahead.

Adding Display Widget

For creating display widget write the following code inside the class app.

display = StringVar ( )

Entry ( self , relief=RIDGE , textvariable=display ,

justify='right'

, bd=30 , bg="powder blue" ) . pack ( side=TOP ,

expand=YES , fill=BOTH )

So now the output is –

Adding Clear Button Widget

Now we will create a clear button. Whenever this button will be pressed all the stuffs from display will be erased. So write the following code for this.

for clearButton in ( [ "C" ] ) :

erase = iCalc ( self , TOP )

for ichar in clearButton :

button ( erase , LEFT , ichar , lambda

storeObj=display , q=ichar : storeObj . set ( '' ) )

And now you can see the output.

Adding Numbers And Symbols Widget

To add numbers and symbols inside the frame, you have to write the following code.

for numButton in ( "789/" , "456*" , "123-" , "0.+" ) :

FunctionNum = iCalc ( self , TOP )

for iEquals in numButton :

button ( FunctionNum , LEFT , iEquals , lambda

storeObj=display , q=iEquals : storeObj

. set ( storeObj . get ( ) + q ) )

And now you can see the output. It's looking cool.

Adding Equal Button

For implementing Equal button write the following code.

EqualButton = iCalc ( self , TOP )

for iEquals in "=" :

if iEquals == '=' :

btniEquals = button ( EqualButton , LEFT , iEquals )

btniEquals . bind ( '<ButtonRelease-1>' , lambda e , s=self ,

storeObj=display : s . calc ( storeObj ) , '+' )

else :

btniEquals = button ( EqualButton , LEFT , iEquals ,

lambda storeObj=display , s=' %s ' % iEquals : storeObj . set

( storeObj . get ( ) + s ) )

So now our calculator looks like as below.

Applying Event Trigger On Widgets

Now the last thing but very important is to apply event triggers on widgets. It means whenever you click any widget some function will be performed. So write the following code

def calc ( self , display ) :

try :

display . set ( eval ( display . get ( ) ) )

except :

display . set ( "ERROR" )

Complete Code For Python Calculator

So now i am collecting and keeping all the above codes in one place. So our entire code for making a simple calculator in python is below.

from tkinter import *

def iCalc ( source , side ) :

storeObj = Frame ( source , borderwidth=4 , bd=4 , bg="powder blue" )

storeObj . pack ( side=side , expand =YES , fill =BOTH )

return storeObj

def button ( source , side , text , command=None ) :

storeObj = Button ( source , text=text , command=command )

storeObj . pack ( side=side , expand = YES , fill=BOTH )

return storeObj

class app ( Frame ) :

def __init__ ( self ) :

Frame . __init__ ( self )

self . option_add ( '*Font' , 'arial 20 bold' )

self . pack ( expand = YES , fill =BOTH )

self . master . title ( 'Calculator' )

display = StringVar ( )

Entry ( self , relief=RIDGE , textvariable=display ,

justify='right'

, bd=30 , bg="powder blue" ) . pack ( side=TOP ,

expand=YES , fill=BOTH )

for clearButton in ( [ "C" ] ) :

erase = iCalc ( self , TOP )

for ichar in clearButton :

button ( erase , LEFT , ichar , lambda

storeObj=display , q=ichar : storeObj . set ( '' ) )

for numButton in ( "789/" , "456*" , "123-" , "0.+" ) :

FunctionNum = iCalc ( self , TOP )

for iEquals in numButton :

button ( FunctionNum , LEFT , iEquals , lambda

storeObj=display , q=iEquals : storeObj

. set ( storeObj . get ( ) + q ) )

EqualButton = iCalc ( self , TOP )

for iEquals in "=" :

if iEquals == '=' :

btniEquals = button ( EqualButton , LEFT , iEquals )

btniEquals . bind ( '<ButtonRelease-1>' , lambda e , s=self ,

storeObj=display : s . calc ( storeObj ) , '+' )

else :

btniEquals = button ( EqualButton , LEFT , iEquals ,

lambda storeObj=display , s=' %s ' % iEquals : storeObj . set

( storeObj . get ( ) + s ) )

def calc ( self , display ) :

try :

display . set ( eval ( display . get ( ) ) )

except :

display . set ( "ERROR" )

if __name__=='__main__' :

app ( ) . mainloop ( )

So now its time to see the calculator and you can perform any operation on it. So let's start your calculation.

Congratulations, We have created python calculator successfully, that's pretty cool, and i hope you have really enjoyed while making this. So surely comment your feelings about this.