Updating tkinter label based on loop

Question

Background Information

Hello. What I'm trying to do currently is create the tkinter window, run a for loop and update the label in real-time as the for loop is running through the directories (in this case, it is listing all the directories with their full paths in the C drive of my computer).

The Problem

The problem that I'm running into is that as soon as I click the start button (which begins the for loop) the GUI completely freezes (I'm aware that this is because tkinter and loops don't play well, I just wonder if there is a solution I'm not aware of), which is counter intuitive as I'd like it to display the directory that the loop is currently iterating over within my tooltip label.

What I've tried so far

from tkinter import Tk, Label, Frame, Button
import os

def start_command():
    for root_directory, sub_directories, files in os.walk("C:\\"):
        for sub_directory in sub_directories:
            full_directory = os.path.join(root_directory, sub_directory)
            tooltip.config(text=full_directory)

window = Tk()
tooltip = Label(window, text="Nothing Here Yet")
tooltip.pack()
start = Button(text="Start", command=start_command)
start.pack()

window.mainloop()

Tl;Dr I'm trying to run a for loop within tkinter and update the label every iteration. The problem is the GUI is freezing with the above code.

Any help would be greatly appreciated. Thank you for your time :)

Answer 1

import tkinter as tk
import os

class MyDirectoryLabel(tk.Label):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.dirGen = self.directoryGen()
        self.master = self._nametowidget(self.winfo_parent())

    def directoryGen(self):
        for root_directory, sub_directories, files in os.walk("C:\\"):
            for sub_directory in sub_directories:
                yield os.path.join(root_directory, sub_directory)

    def loop(self):
        try:
            full_directory = next(self.dirGen)
        except StopIteration as e:
            self.config(text = "Finished...")
            return 0

        self.config(text = full_directory)

        self.master.after(10, self.loop)        

root     = tk.Tk()
root.geometry("500x100")

tooltip = MyDirectoryLabel(root, text = "Nothing Here Yet")
start   = tk.Button(root, text = "Start", command = tooltip.loop)

tooltip.pack()
start.pack()

root.mainloop()

Uses the after method in combination with a generator which creates the directory for the label.