binding not working tkinter python3

Question

so I'm working on a rubics cube timer in python 3 (using tkinter).

I am trying to make it so that when you press space, the timer stops (originally i tried to do this for starting and stopping but i found it too hard) I have tried to bind the space key to my Stop function but it either returns an error (when I ommit a set of parenthesis after naming the function to bind to, it for some stupid reason thinks I'm passing 2 arguments. idk why this happens) or doesnt work at all. here is my code, Thx in advance for the solution.

from tkinter import *
import time

class StopWatch(Frame):  
""" Implements a stop watch frame widget. """                                                                
    def __init__(self, parent=None, **kw):        
        Frame.__init__(self, parent, kw)
        self._start = 0.0        
        self._elapsedtime = 0.0
        self._running = 0
        self.timestr = StringVar()               
        self.makeWidgets()


    def makeWidgets(self):                         
        """ Make the time label. """
        l = Label(self, textvariable=self.timestr)
        self._setTime(self._elapsedtime)
        l.pack(fill=X, expand=NO, pady=2, padx=2)                      

    def _update(self): 
        """ Update the label with elapsed time. """
        self._elapsedtime = time.time() - self._start
        self._setTime(self._elapsedtime)
        self._timer = self.after(50, self._update)

    def _setTime(self, elap):
        """ Set the time string to Minutes:Seconds:Hundreths """
        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))

    def Start(self):                                                     
        """ Start the stopwatch, ignore if running. """
        if not self._running:            
            self._start = time.time() - self._elapsedtime
            self._update()
            self._running = 1        

    def Stop(self):                                    
    """ Stop the stopwatch, ignore if stopped. """
        if self._running:
            self.after_cancel(self._timer)            
            self._elapsedtime = time.time() - self._start    
            self._setTime(self._elapsedtime)
            self._running = 0
            print("fsddaewSDGNFHRAW") # a test to see if it works

    def Reset(self):                                  
    """ Reset the stopwatch. """
        self._start = time.time()         
        self._elapsedtime = 0.0    
        self._setTime(self._elapsedtime)

def main():

    root = Tk()
    sw = StopWatch(root)
    root.bind("<space>",sw.Stop()) # this is where i tried to bind
    # if i did this:
    #root.bind("<space>",sw.stop) it would say im passing 2 parameters instead of one (self)
    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()

score 1 · Accepted Answer · answered Jul 03 '17 at 00:16

You are very close.

First, the bind function needs the function itself as an argument. Since you have the () on the end, you are passing the result of running the function, in this case None. Just leave those off:

root.bind("<space>",sw.Stop)

Second, the function that bind calls must accept an event argument. So you need to define it like this:

def Stop(self, event=None):

binding not working tkinter python3

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