无法更改按钮颜色，因为未定义-Python .Tkinter

Question

trying to configure button so that it changes color once clicked.

from tkinter import *

root = Tk()

def  buttonsMake():
    for c in range(10):
        for r in range(3):
            movieSeats=Button(root, text="Empty", bg="green", fg="white", 
width=5, height=1, command=lambda c=c, r=r:[redClick(c, r)])
            movieSeats.grid(row=r,column=c)


def redClick(c, r):
    movieSeats.configure(bg="red")



buttonsMake()
root.mainloop()

I expect it to change color Here's the error:

movieSeats=Button(root, text="Empty", bg="green", fg="white", width=5, 
height=1, command=lambda c=c, r=r:[redClick(c, r)])
  File "C:/Users/----/Downloads/test2.py", line 21, in redClick
    movieSeats.configure(bg="red")
NameError: name 'movieSeats' is not defined

Answer 1

movieSeats is local variable in buttonsMake() so it doesn't exist in redClick and you get error name 'movieSeats' is not defined

You have to use global movieSeats in buttonsMake() to create global variable.

---

BTW:

You assing all buttons to the same variable so you have access only to last button. You can keep all buttons on list or send it to redClick as parameter

import tkinter as tk

# --- functions ---

def make_buttons():

    for c in range(10):
        for r in range(3):
            btn = tk.Button(root, text="Empty")
            btn['command'] = lambda c=c, r=r, b=btn:red_click(c, r, b)
            btn.grid(row=r,column=c)

def red_click(c, r, btn):
    btn.configure(bg="red")

# --- main ---

root = tk.Tk()

make_buttons()

root.mainloop()