Tkinter Checkbox

Summary: in this tutorial, you’ll learn about the Tkinter Checkbox widget and how to use it effectively.

Introduction to the Tkinter checkbox widget #

A checkbox is a widget that allows you to check and uncheck. A checkbox can hold a value and invoke a function automatically when its state changes.

Typically, you use a checkbox when you want to ask users to choose between two values.

To create a checkbox, you use the ttk.Checkbutton constructor:

checkbox = ttk.Checkbutton(
    master,
    text='<checkbox label>',
    command=callback,
    variable=variable,
    onvalue='<value_when_checked>',
    offvalue='<value_when_unchecked>'
)Code language: Python (python)

In this syntax:

• The master argument specifies the master widget that you want to place the checkbox.
• The text argument specifies the label for the checkbox.
• The command is a callable that will be called once the checkbox is checked or unchecked.
• The variable holds the current value of the checkbox. Typically, you use a BooleanVar object to track whether the checkbox is checked or not. If you want other values than True and False, you can specify them in the onvalue and offvalue options.

Tkinter checkbox example #

The following program illustrates how to use a checkbox widget. Once you check or uncheck the checkbox, a message box will show the on value and the off value accordingly:

import tkinter as tk
from tkinter import ttk
from tkinter.messagebox import showinfo

root = tk.Tk()
root.geometry('300x200')
root.title('Checkbox Demo')


def show_message():
    showinfo(
        title='Result',
        message='You agreed.' if agreement_var.get() else 'You did not agree.'
    )


agreement_var = tk.BooleanVar()

checkbox = ttk.Checkbutton(
    root,
    text='I agree',
    command=show_message,
    variable=agreement_var
)

checkbox.pack()


root.mainloop()Code language: Python (python)

Output:

How it works.

First, create a BooleanVar object that will hold the the state of the checkbox:

agreement_var = tk.BooleanVar()

Second, define a function that will execute when the state of the checkbox changes. The function shows a message whether you check or uncheck the checkbox:

def show_message():
    showinfo(
        title='Result',
        message='You agreed.' if agreement_var.get() else 'You did not agree.'
    )Code language: JavaScript (javascript)

Third, create a checkbox widget and set its options accordingly:

checkbox = ttk.Checkbutton(
    root,
    text='I agree',
    command=show_message,
    variable=agreement_var
)Code language: JavaScript (javascript)

Summary #

• Use Checkbutton() to create a checkbox.
• Use command argument to specify a function that executes when the button is checked or unchecked.
• Use the onvalue and offvalue to determine what value the variable will take.