登录屏幕哪里出了问题（Def Login）

Question

I'm working on some school work and i'm developing an app for car rentals, im working on the basics and learning as i go along. The rest of the app is working so far but im looking into why my user login screen isn't functioning.

I've tried implementing some of the similar code within my register screen (which works flawlessly) but the code launches, but when i press login i'm not getting any windows showing, it may be a simple mistake, but it's likely due to my lack of experience haha, i've also tried working with the global variables, but that is where i feel i lack my most knowledge in understand global variables and where to use them appropriately.

import tkinter as tk

def register():
    top = tk.Toplevel(root)  # create a GUI window
    top.title("Register")
    top.geometry("400x350")
    username = tk.StringVar(top)
    password = tk.StringVar(top)
    email = tk.StringVar(top)
    tk.Label(top, text="Please enter your details below", bg="red").pack()
    tk.Label(top, text="Email * ").pack()
    tk.Entry(top, textvariable=email).pack(padx=10, pady=10)
    tk.Label(top, text="Username * ").pack()
    tk.Entry(top, textvariable=username).pack(padx=10, pady=10)
    tk.Label(top, text="Password * ").pack()
    tk.Entry(top, textvariable=password, show='*').pack(padx=10, pady=10)
    tk.Button(top, text="Register", width=10, height=2, bg="red").pack()

def login():
    login_screen = tk.Toplevel(root) 
    login_screen.title("Login")  
    login_screen.geometry("300x250") 
    username_verify = tk.StringVar(login_screen) 
    password_verify = tk.StringVar(login_screen)
    tk.Label(login_screen, text="Please enter details below to login").pack()
    tk.Label(login_screen, text="").pack()

    global username_login_entry
    global password_login_entry

    tk.Label(login_screen, text="Username * ").pack()
    username_login_entry = tk.Entry(login_screen, textvariable=username_verify)
    username_login_entry.pack()
    tk.Label(login_screen, text="").pack()
    tk.Label(login_screen, text="Password * ").pack()
    password_login_entry = tk.Entry(login_screen, textvariable=password_verify, show='*')
    password_login_entry.pack()
    tk.Label(login_screen, text="").pack()
    tk.Button(login_screen, text="Login", width=10, height=1, command=login_verify).pack()

root = tk.Tk()
root.geometry("700x450")
root.title("Account Login")
root.wm_iconbitmap('py.ico')
tk.Label(root, text="Login or Register", bg="red", width="300", height="2", font=("Arial Black", 13,)).pack()
tk.Button(root, text="Login", height="4", width="30", font=("Arial Black", 13,)).pack(padx=15, pady=15)
tk.Button(root, text="Register", height="4", width="30", font=("Arial Black", 13,), command=register).pack()

root.mainloop()

In this code im particularly looking at the Def Login part of the code but i provided all of my lines so far as context to help you understand if there are any issues that are linking to the other functions. The expected output would be where the login window opens when clicked.

Answer 1

You've done the definition correctly, however you've never used that function anywhere. Notice how the register function has been called through this line

tk.Button(root, text="Register", height="4", width="30", font=("Arial Black", 13,), command=register).pack()

command=register is what calls the function upon pressing the button. However, you don't have a command associated with your login button.

tk.Button(root, text="Login", height="4", width="30", font=("Arial Black", 13,)).pack(padx=15, pady=15)

Notice the lack of a command attribute. I'm sure you know what to do now:)

Remember one thing in your login definition. In the very last line, you're calling command=login_verify . I'm assuming you simply have that as a placeholder for a function you'll be working on later but that will throw an exception, just letting you know.