How do I handle the window close event in Tkinter?

python events tkinter window
Matt Gregory picture Matt Gregory · Sep 21, 2008 · Viewed 147.3k times · Source

How do I handle the window close event (user clicking the 'X' button) in a Python Tkinter program?

Answer

Matt Gregory picture Matt Gregory · Sep 21, 2008

Tkinter supports a mechanism called protocol handlers. Here, the term protocol refers to the interaction between the application and the window manager. The most commonly used protocol is called WM_DELETE_WINDOW, and is used to define what happens when the user explicitly closes a window using the window manager.

You can use the protocol method to install a handler for this protocol (the widget must be a Tk or Toplevel widget):

Here you have a concrete example:

import tkinter as tk
from tkinter import messagebox

root = tk.Tk()

def on_closing():
    if messagebox.askokcancel("Quit", "Do you want to quit?"):
        root.destroy()

root.protocol("WM_DELETE_WINDOW", on_closing)
root.mainloop()

Related questions

How do you run your own code alongside Tkinter's event loop?

My little brother is just getting into programming, and for his Science Fair project, he's doing a simulation of a flock of birds in the sky. He's gotten most of his code written, and it works nicely, but the birds …

Read More
How to set the text/value/content of an `Entry` widget using a button in tkinter

I am trying to set the text of an Entry widget using a button in a GUI using the tkinter module. This GUI is to help me classify thousands of words into five categories. Each of the categories has a …

Read More
Getting a callback when a Tkinter Listbox selection is changed?

There are a number of ways of getting callbacks when Text or Entry widgets are changed in Tkinter, but I haven't found one for Listbox's (it doesn't help that much of the event documentation I can find is old or …

Read More