I wanna make a stopwatch with python

Question

import tkinter as tk
import time

timer = 0

def startTimer():
    if timer == 0:
        time.sleep(1)
    elif (running):
        global timer
        timer += 1
        timeText.configure(text=str(timer))
    window.after(1000, startTimer)
    
def start():
    global running
    running = True
    
def stop():
    global running
    running = False

running = True

window = tk.Tk()


timeText = tk.Label(window, text = '0', font=("Helvetica", 80))
timeText.pack()

startButton = tk.Button(window, text = 'Start', bg='yellow', command=start)
startButton.pack(fill=tk.BOTH)

stopButton = tk.Button(window, text = 'Stop', bg='yellow', command=stop)
stopButton.pack(fill=tk.BOTH)

startTimer()
window.mainloop()

I wanted to make a stopwatch with python but I have question to you to solve this problem. when I execute this, I can find

line 10
global timer
^
SyntaxError: name 'timer' is used prior to global declaration

this error.

I tried to make this stopwatch to start without I press start button. And, I want this stopwatch to start at 0.

Can you change my code to solve the problem?

Move global timer to the line before if timer==0 in startTimer function — ThePyGuy
– ThePyGuy, Commented Sep 4, 2022 at 16:05

Mario · Accepted Answer · 2022-09-06 16:54:53Z

0

In order for the stopwatch to work you should fix two issues: you must declare as global both running and timer, since both are used in the startTimer function, and you should address the infinite loop that happens in the if timer == 0 part. You see, if when timer is 0 all the script does is wait, then it will never increment and thus loop indefinitely. Both issues are fixed by the code below.

def startTimer():
    global timer
    global running
    if timer == 0:
        time.sleep(1)
        timer += 1
    elif running:
        timer += 1
        timeText.configure(text=str(timer))
    window.after(1000, startTimer)

Keep in mind though that tkinter does not behave well with time, generally speaking.

edited Sep 6, 2022 at 16:54

answered Sep 4, 2022 at 16:05

Mario

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2 Comments

Gryphinx Over a year ago

It doesn't work... The error has gone but the timer doesn't count.

Mario Over a year ago

@Gryphinx I've edited my answer, take a look at it and let me know what you think.

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