错误：当我尝试添加标签时，由按钮提示创建的新窗口未定义

Question

我正在为学校做一个口袋妖怪游戏。首先，我有一个名为“登录”的开始游戏屏幕，用户必须在此屏幕上按下按钮，按下该按钮将触发一个新的窗口菜单，并关闭旧的登录屏幕。这种情况会发生，但在play（）函数的主代码中，当我尝试向新屏幕菜单添加图像标签时，它会说菜单未定义。如果有人能帮忙，我将不胜感激。我的意图是不使用课堂，因为到目前为止我们还没有在课堂上学习到这一点

from tkinter import *
from tkinter import messagebox

login = Tk()
login.title("Pokemon")
login.geometry('1000x750')
login.resizable(False, False)

background_image=PhotoImage(file='background.png')
background_label = Label(login, image=background_image)
background_label.place(x=0, y=0, relwidth=1, relheight=1)

title = PhotoImage(file='title.png')

lbl = Label(login, image = title)
lbl.place(x=25, y=20)

messagebox.showinfo('WELCOME TO MY POKEMON GAME', 'HOPE YOU HAVE A GREAT TIME :)')

def play():
    global menu
    global login
    menu = Tk()
    menu.title("Pokemon Main Menu")
    menu.geometry('1000x750')
    menu.resizable(False, False)
    login.destroy()

begin= PhotoImage(file='begin.png')


btn = Button(login, image=begin, command = play)
btn.place(x=75, y=300)

background_image2=PhotoImage(file='background2.png')
background_label2 = Label(menu, image=background_image2)
background_label2.place(x=0, y=0, relwidth=1, relheight=1)


menu.mainloop()
login.mainloop()

这是我一直收到的错误

 Traceback (most recent call last):
  File "/Users/ishaan/Desktop/attachments/Pokemon.py", line 39, in <module>
    background_label2 = Label(menu, image=background_image2)
NameError: name 'menu' is not defined

Answer 1

你的问题是错误的缩进

您必须在play()内部创建标签，但在play()外部创建标签，所以它在开始时执行，而不是在您按下按钮时执行，所以它会在创建menu之前尝试添加标签

from tkinter import *
from tkinter import messagebox

# - functions  -

def play():
    global menu
    global login

    login.destroy()

    menu = Tk()
    menu.title("Pokemon Main Menu")
    menu.geometry('1000x750')
    menu.resizable(False, False)

    background_image2 = PhotoImage(file='background2.png')
    background_label2 = Label(menu, image=background_image2)
    background_label2.place(x=0, y=0, relwidth=1, relheight=1)

    menu.mainloop()

#  - main  -

login = Tk()
login.title("Pokemon")
login.geometry('1000x750')
login.resizable(False, False)

background_image = PhotoImage(file='background.png')
background_label = Label(login, image=background_image)
background_label.place(x=0, y=0, relwidth=1, relheight=1)

title = PhotoImage(file='title.png')
lbl = Label(login, image=title)
lbl.place(x=25, y=20)

btn = Button(login, command=play)
btn.place(x=75, y=300)

messagebox.showinfo('WELCOME TO MY POKEMON GAME', 'HOPE YOU HAVE A GREAT TIME :)')

login.mainloop()