Scheduling actions

A basic technique to prevent blocking the main thread in Tkinter is scheduling an action that will be invoked after a timeout has elapsed.

In this recipe, we will take a look at how to implement this with Tkinter using the after() method, which can be called from all Tkinter widget classes.

Getting ready

The following code shows a straightforward example of how a callback can block the main loop.

This application consists of a single button that gets disabled when it is clicked, waits 5 seconds, and is enabled again. A trivial implementation would be the following one:

import time
import tkinter as tk

class App(tk.Tk):
    def __init__(self):
        super().__init__()
        self.button = tk.Button(self, command=self.start_action,
                                text="Wait 5 seconds")
        self.button.pack(padx=20, pady=20)

    def start_action(self):
        self.button.config(state=tk.DISABLED)
        time.sleep(5)
        self.button.config(state=tk.NORMAL)

if __name__...