TKinter - How to stop a loop with a stop button?

Question

I have this program which beeps every second until it\'s stopped. The problem is that after I press \"Start\" and the beeps starts, I cannot click the \"Stop\" button becaus

Answer 1

You code have top.mainloop() which has a while loop running inside it and on top of that you also have a while loop inside def start():. So it is like loop inside loop.

You can create a function that does what you want for the body of the loop. It should do exactly one iteration of the loop. Once it is done, it needs to arrange for itself to be called again some time in the future using after. How far in the future defines how fast your loop runs.

And you can then use after_cancel to cancel the event. Below code worked for me

import Tkinter, tkMessageBox, time, winsound, msvcrt

Freq = 2500
Dur = 150

top = tkinter.Tk()
top.title('MapAwareness')
top.geometry('200x100') # Size 200, 200

def start():
    global job1
    if running == True:
        winsound.Beep(Freq, Dur)
        job1 = top.after(1000, start)  # reschedule event in 1 seconds

def stop():
    global job1
    top.after_cancel(job1)

startButton = tkinter.Button(top, height=2, width=20, text ="Start", command = start)
stopButton = tkinter.Button(top, height=2, width=20, text ="Stop", command = stop)

startButton.pack()
stopButton.pack()
#top.after(1000, start)
top.mainloop()