Python Tkinter Stopwatch Error

i have made a double countdown timer with python and tkinter but it seemed that it cannot be run if the tkinter window is not on the foreground and it cannot simultaneously run. Th

Solution 1:

The calls to time.sleep are at least part of the problem. When you call sleep it does literally that -- it puts the application to sleep. No events can be processed and the GUI freezes. This is the wrong way to do a countdown timer.

The other problem is the calls to update inside the loops alongside the calls to time.sleep. This call will process events, which means that when one of the loops is running and you click a button, you may end up calling the other function, interleaving your two loops.

The proper way to do something periodically is to use after to repeatedly call a function. The general pattern is this:

defupdate_display(self):
    <do whatever code you want to update the display>
    root.after(1000, self.update_display)

You can have as many of these running in parallel that you want (up to practical limits, obviously), and your GUI will be completely responsive between updates.

Here's a quick example:

classCountdown(tk.Label):
    def__init__(self, parent):
        tk.Label.__init__(self, parent, width=5, text="00:00")
        self.value = 0
        self._job_id = Nonedeftick(self):
        self.value -= 1
        text = "{:02d}:{:02d}".format(*divmod(self.value, 60))
        self.configure(text=text)
        if self.value > 0:
            self._job_id = self.after(1000, self.tick)

    defstart(self, starting_value=60):
        if self._job_id isnotNone: return

        self.value = starting_value
        self.stop_requested = False
        self.after(1000, self.tick)

    defstop(self):
        self.after_cancel(self._job_id)
        self._job_id = None

Solution 2:

This is a simple tkinter(gui) stopwatch I made which works perfectly. Check it out

__author__ = 'Surya'from tkinter import *
import time
classStopWatch(Frame):
    def__init__(self, parent = None, ** kw):
        Frame.__init__(self, parent, kw)
        self._timeelapsed = 0.0
        self._start = 0.0
        self._run = 0
        self.timestr = StringVar()
        self.makeWidgets()
    defmakeWidgets(self):
        l = Label(self, textvariable=self.timestr)
        self._setTime(self._timeelapsed)
        l.pack(fill=X, expand=NO, pady=2, padx=2)

    def_update(self):
        self._timeelapsed = time.time() - self._start
        self._setTime(self._timeelapsed)
        self._timer = self.after(50, self._update)

    def_setTime(self, elap):
        minutes = int(elap/60)
        seconds = int(elap - minutes*60.0)
        hseconds = int((elap - minutes*60.0 - seconds)*100)
        self.timestr.set('%02d:%02d:%02d' % (minutes, seconds, hseconds))

    defStart(self):
        ifnot self._run:
            self._start = time.time() - self._timeelapsed
            self._update()
            self._run = 1defStop(self):
        if self._run:
            self.after_cancel(self._timer)
            self._timeelapsed = time.time() - self._start
            self._setTime(self._timeelapsed)
            self._run = 0defReset(self):
        self._start = time.time()
        self._timeelapsed = 0.0
        self._setTime(self._timeelapsed)


defmain():
    root = Tk()
    sw = StopWatch(root)
    sw.pack(side=TOP)
    Button(root, text='Start!', command=sw.Start).pack(side=LEFT)
    Button(root, text='Stop!', command=sw.Stop).pack(side=LEFT)
    Button(root, text='Reset!!!', command=sw.Reset).pack(side=LEFT)
    Button(root, text='Quit!!!', command=root.quit).pack(side=LEFT)

    root.mainloop()

if __name__ == '__main__':
        main()