Python GUI Programming with Tkinter

The after() and after_idle() methods

Tkinter widgets have two methods for adding arbitrary code to the event queue on a delay: after() and after_idle().

Basic use of after() looks like this:

import tkinter as tk
root = tk.Tk()
root.after(1000, root.quit)
root.mainloop()

In this example, we're setting root.quit to run after 1 second (1,000 milliseconds). In the background, root.quit is added to the event loop, but with the condition that it shouldn't be executed until at least 1 second from when after() was called. During that 1 second, any other events in the queue will be executed first. The command might be executed later than 1 second, depending on what's being processed already in the event queue, but no sooner.

The after_idle() method ...