Tkinter Example

Summary: in this tutorial, you’ll learn how to build a Tkinter temperature converter application.

Introduction to the Temperature Converter application

The following shows the Temperature Converter application that you’re going to build. The application converts a temperature from Fahrenheit to Celsius:

Basically, the application has a label, an entry, and a button. When you enter a temperature in Fahrenheit and click the Convert button, it’ll convert the value in the textbox from Fahrenheit to Celsius.

If you enter a value that cannot be converted to a number, the program will show an error.

To build this application, you follow these steps.

First, import the tkinter module, ttk submodule, and the showerror function from tkinter.messagebox:

import tkinter as tk from tkinter import ttk from tkinter.messagebox import showerror
Code language: Python (python)

Second, create the root window and set its configurations:

# root window root = tk.Tk() root.title('Temperature Converter') root.geometry('300x70') root.resizable(False, False)
Code language: Python (python)

Third, define a function that converts a temperature from Fahrenheit to Celsius:

def fahrenheit_to_celsius(f): """ Convert fahrenheit to celsius """ return (f - 32) * 5/9
Code language: Python (python)

Fourth, create a frame that holds form fields:

frame = ttk.Frame(root)
Code language: Python (python)

Fifth, define an option that will be used by all the form fields:

options = {'padx': 5, 'pady': 5}
Code language: Python (python)

Sixth, define the label, entry, and button. The label will show the result once you click the Convert button:

# temperature label temperature_label = ttk.Label(frame, text='Fahrenheit') temperature_label.grid(column=0, row=0, sticky='W', **options) # temperature entry temperature_entry = ttk.Entry(frame, textvariable=temperature) temperature_entry.grid(column=1, row=0, **options) temperature_entry.focus() # convert button convert_button = ttk.Button(frame, text='Convert') convert_button.grid(column=2, row=0, sticky='W', **options) convert_button.configure(command=convert_button_clicked) # result label result_label = ttk.Label(frame) result_label.grid(row=1, columnspan=3, **options)
Code language: Python (python)

Finally, place the frame on the root window and run the mainloop() method:

frame.grid(padx=10, pady=10) root.mainloop()
Code language: Python (python)

Put it all together.

import tkinter as tk from tkinter import ttk from tkinter.messagebox import showerror # root window root = tk.Tk() root.title('Temperature Converter') root.geometry('300x70') root.resizable(False, False) def fahrenheit_to_celsius(f): """ Convert fahrenheit to celsius """ return (f - 32) * 5/9 # frame frame = ttk.Frame(root) # field options options = {'padx': 5, 'pady': 5} # temperature label temperature_label = ttk.Label(frame, text='Fahrenheit') temperature_label.grid(column=0, row=0, sticky='W', **options) # temperature entry temperature = tk.StringVar() temperature_entry = ttk.Entry(frame, textvariable=temperature) temperature_entry.grid(column=1, row=0, **options) temperature_entry.focus() # convert button def convert_button_clicked(): """ Handle convert button click event """ try: f = float(temperature.get()) c = fahrenheit_to_celsius(f) result = f'{f} Fahrenheit = {c:.2f} Celsius' result_label.config(text=result) except ValueError as error: showerror(title='Error', message=error) convert_button = ttk.Button(frame, text='Convert') convert_button.grid(column=2, row=0, sticky='W', **options) convert_button.configure(command=convert_button_clicked) # result label result_label = ttk.Label(frame) result_label.grid(row=1, columnspan=3, **options) # add padding to the frame and show it frame.grid(padx=10, pady=10) # start the app root.mainloop()
Code language: Python (python)

In this tutorial, you’ve learned how to develop a simple Tkinter application that converts a temperature from Fahrenheit to Celsius.

Did you find this tutorial helpful ?