tkinter canvas item configure

Question

I'm trying to make a dice object, and I want to be able to control the pip colors. I created the pips with a black fill, and I tried to change one to red using

self.canvas.itemconfigure(self.pip1, fill='red') 

but it seems to have no effect. There is no error so I'm wondering why the change doesn't show up.

Minimum working example:

from tkinter import *
from tkinter import ttk

class Dice:
    #the x and y instancing variables are for the x and y coordinates of the top left corner of the rectangle
    def __init__(self, win, x, y):
        self.win = win
        self.win.geometry("500x500")
        self.canvas = Canvas(self.win)
        self.canvas.place(x=0, y=0)

        die = self.canvas.create_rectangle(x, y, x+88, y+88, fill='white', width=1)
        offset = 20

        #create 7 circles for pip locations:

        self.pip1 = self.pips(x+offset, y+offset)
        self.pip2 = self.pips(x+offset, y+2*offset)
        self.pip3 = self.pips(x+offset, y+3*offset)
        self.pip4 = self.pips(x+2*offset, y+2*offset)
        self.pip5 = self.pips(x+3*offset, y+offset)
        self.pip6 = self.pips(x+3*offset, y+2*offset)
        self.pip7 = self.pips(x+3*offset, y+3*offset)

        self.canvas.itemconfigure(self.pip1, fill='red')

    def pips(self, x, y):
        pip = self.canvas.create_oval(x, y, x+9, y+9, fill='black', width=0)

    #def setValue(self, value)

    #def pipsOff(self, pip):



def test():
    x = Dice(Tk(), 50, 50)
    mainloop()

Answer 1

First rule of debugging: examine your data. If you put a print statement or stop the debugger just before the call to itemconfigure you will see that self.pip1 has a value of None . So the first thing you should ask yourself is, "why is it None ?"

The reason it is None is that you create it in a method but neglect to return the item id. So, the fix to your problem is to add return pip at the end of the function pips :

def pips(self, x, y):
    pip = self.canvas.create_oval(x, y, x+9, y+9, fill='black', width=0)
    return pip