我无法从我的 Button 获得退货 - Python Tkinter

Question

I'm pretty new to Tkinter and I'm trying to get a return from my button in messagebox using command=function but nothing seems to happen:

import tkinter as tk
from tkinter import messagebox

def start_game(dif):
    root = tk.Tk()
    root.attributes("-topmost", True)
    root.withdraw()
    answer = messagebox.askyesno("Welcome to Snake!", "Would you like to play?")
    if answer == True:
        root.deiconify()
        mainLabel = tk.Label(root, text='Choose a dificulty: ')

        def easy_difficulty():
            return dif + 1
            root.destroy()
        def hard_difficulty():
            return dif + 10
            root.destroy()

        easy_ask = tk.Button(root, text='Easy', command=easy_difficulty)
        hard_ask = tk.Button(root, text='Hard', command=hard_difficulty)
        
        mainLabel.pack()
        easy_ask.pack(side=tk.LEFT)
        hard_ask.pack(side=tk.LEFT)

    root.mainloop()

difficulty = start_game(0)
print(difficulty)

Answer 1

The problem here is that there is nowhere to return dif+1 nor dif+10

If what you need is that value, 1 or 10, what I would suggest is to create a global variable, lets call it Dif.

Dif = 0

and in the easy or hard difficulty function instead of return dif + 1 or 10 you need to fistable call the variable in the following way:

global Dif

and then:

Dif = dif+1       # or 10 if its int the hard function

Answer 2

You don't need to return value in easy_difficulty() and hard_difficulty() . Just update the passed argument dif and return dif after root.mainloop() . However you need declare dif as nonlocal inside easy_difficulty() and hard_difficulty() , otherwise it is treated as local variable:

Below is a modified code:

import tkinter as tk
from tkinter import messagebox

def start_game(dif):
    root = tk.Tk()
    root.attributes("-topmost", True)
    root.withdraw()
    answer = messagebox.askyesno("Welcome to Snake!", "Would you like to play?")
    if answer == True:
        root.deiconify()
        mainLabel = tk.Label(root, text='Choose a dificulty: ')

        def easy_difficulty():
            nonlocal dif
            dif += 1
            root.destroy()

        def hard_difficulty():
            nonlocal dif
            dif += 10
            root.destroy()

        easy_ask = tk.Button(root, text='Easy', command=easy_difficulty)
        hard_ask = tk.Button(root, text='Hard', command=hard_difficulty)
        
        mainLabel.pack()
        easy_ask.pack(side=tk.LEFT)
        hard_ask.pack(side=tk.LEFT)

        root.mainloop()
    else:
        root.destroy()
    # return the updated 'dif'
    return dif

difficulty = start_game(0)
print(difficulty)