responsible GUI with multiprocessing.

gui.py

# -*- coding: utf-8 -*-
from datetime import datetime
from multiprocessing import Process
from time import sleep
import tkinter as tk


class Application(tk.Frame):
    def __init__(self, master=None):
        tk.Frame.__init__(self, master)
        self.pack()
        self.createWidgets()
        self.is_parent = True
        # self.doing_work = False

    def createWidgets(self):
        self.hi_there = tk.Button(self)
        self.hi_there['text'] = 'Do Work!\n(clikc me)'
        self.hi_there['command'] = self.issue_command
        self.hi_there.pack(side='top')

        self.QUIT = tk.Button(self, text='QUIT', fg='red',
                              command=self.i_quit)

        self.QUIT.pack(side='bottom')

    def check_process(self):
        self.mt.join(0.1)
        if self.mt.is_alive():
            self.after(500, self.check_process)
        else:
            print("ok")

    def issue_command(self):
        self.mt = Process(target=self.do_work)
        self.mt.start()
        # self.check_process()

    def do_work(self):
        self.is_parent = False
        while True:
            print(datetime.now())
            sleep(0.5)

    def i_quit(self):
        self.mt.terminate()
        while True:
            print('waiting for thread ending...')
            self.mt.join(1.0)
            if not self.mt.is_alive():
                if self.is_parent:
                    self.master.destroy()
                return

root = tk.Tk()
app = Application(master=root)
app.mainloop()