出现错误NameError：未为tkinter登录系统定义名称“ main_screen”

Question

我不断收到错误

Traceback (most recent call last):
  File "G:/computing project/test2.py", line 21, in <module>
    main_screen.mainloop() # start the GUI
NameError: name 'main_screen' is not defined

在尝试创建简单的tkinter登录系统时，我尝试将main_screen.mainloop更改为TK.mainloop

from tkinter import*


def main_account_screen():

    main_screen = Tk()   # create a GUI window 
    main_screen.geometry("1920x1080") # set the configuration of GUI window 
    main_screen.title("Account Login") # set the title of GUI window

# create a Form label 
Label(text="Choose Login Or Register", bg="blue", width="300", height="2", font=("Calibri", 13)).pack() 
Label(text="").pack() 

# create Login Button 
Button(text="Login", height="2", width="30").pack() 
Label(text="").pack() 

# create a register button
Button(text="Register", height="2", width="30").pack()

main_screen.mainloop() # start the GUI

main_account_screen() # call the main_account_screen() function

Answer 1

如果您不希望出现任何错误，可以尝试使用此代码段

from tkinter import *

main_screen = Tk()  # create a GUI window


def main_account_screen():
    global main_screen
    main_screen.geometry("1920x1080")  # set the configuration of GUI window
    main_screen.title("Account Login")  # set the title of GUI window


# create a Form label
Label(text="Choose Login Or Register", bg="blue", width="300", height="2", font=("Calibri", 13)).pack()
Label(text="").pack()

# create Login Button
Button(text="Login", height="2", width="30").pack()
Label(text="").pack()

# create a register button
Button(text="Register", height="2", width="30").pack()

main_screen.mainloop()  # start the GUI

main_account_screen()  # call the main_account_screen() function

当您使用global关键字时，这将完全正常