Tkinter: Updating Label with New Background Color (Python 3.5.3) - python-3.x

Question

I am designing a simple timer using Tkinter that changes color after a certain amount of time has elasped. I have a base timer program which works well, but now I want to modify it so the background changes color.
I have if statements that trigger on the appropriate intervals and then change the class attribute assigned to the background color, but I can't get the label color to update.
I understand the "makeWidgets" function runs only once and believe this is likely the source of my problem. I've experimented breaking out this function into the main program with mixed success. I am able to get the timer to work, but still cannot get the color to change. I have also tried writing a color change function/s but haven't had any success. I am inexperienced with python, tkinter and full-disclosure, I did not design the bulk of the base timer program.
I would really appreciate any direction/advice on how to get this working. I feel that I am either close, or in need of a complete re-work. Hopefully, the former is the case.
from tkinter import *
import time
class StopWatch(Frame):
global mincount
""" 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()
self.color = 'green'
def makeWidgets(self): #this function only run once at setup
""" Make the time label. """
self.color='green' #this works
l = Label(self, textvariable=self.timestr, bg=self.color, font=("Helvetica",300), width=12, height=2)
self.setTime(self.elapsedtime)
l.pack(fill=X, expand=YES, 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,):
global mincount
""" 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))
mincount = int(elap)
if mincount>=3:
print("yellow")
self.color='yellow' #has no effect
l.config(bg='yellow') #not in scope
#CHANGE COLOR TO YELLOW - call fx?
if mincount>=5:
print("red")
#CHANGE COLOR TO RED
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
def Reset(self):
""" Reset the stopwatch. """
self.start = time.time()
self.elapsedtime = 0.0
self.setTime(self.elapsedtime)
self.color='green'
def main():
root = Tk()
sw = StopWatch(root)
sw.pack(side=TOP)
Button(root, text='Start', command=sw.Start).pack(side=BOTTOM, fill=BOTH)
Button(root, text='Stop', command=sw.Stop).pack(side=BOTTOM, fill=BOTH)
Button(root, text='Reset', command=sw.Reset).pack(side=BOTTOM, fill=BOTH)
Button(root, text='Quit', command=root.quit).pack(side=BOTTOM, fill=BOTH)
current=sw.timestr
root.mainloop()
if __name__ == '__main__':
main()

Answer 1

You can't use l in your setTime function : l is a local variable in makeWidgets
it can't be used in setTime. To fix it you have to make l a variable part of the class in makeWidgets : self.label = ... for exemple. And after that use your new variable self.label in setTime : self.label.config("bg"="yellow")
Something can be improved in your if statement if mincount>=3: because if it's true you change the bg and after that you check if mincount>=5. You should do this:
if mincount>=5:
...
elif mincount >=3:
...