from __future__ import print_function
import tkinter
import random
import string
import sys
import threading
import time

running = True


class EventThread(threading.Thread):
    def __init__(self,target):
        super(EventThread,self).__init__()
        self.target = target
    def run(self):
        tid = self.ident
        while running:
            time.sleep(0.02)
            c = random.choice(string.ascii_letters)
            print("%d: sending '%s'"%(tid,c),file=sys.stderr)
            self.target.event_generate(c)

class Main(object):
    def __init__(self):
        self.root = tkinter.Tk()
        self.root.bind('<Key>',dummy_handler)
        self.threads=[]

    def go(self):
        self.root.after(20,self.add_threads)
        self.root.after(5000,self.stop)
        self.root.mainloop()
    def stop(self):
        global running
        running = False
        for t in self.threads: t.join()
        self.root.destroy()
    def add_threads(self):
        for _ in range(2):
            t = EventThread(self.root)
            self.threads.append(t)
            t.start()

def dummy_handler(event):
    tid = threading.current_thread().ident
    print("%d: received: '%s'"%(tid,event.keysym),file=sys.stderr)

if __name__ == '__main__':
    Main().go()