python - 用户登录后调用 displayMenu() 函数

Question

用户应使用他/她的用户名和密码登录。如果用户是管理员，那么他应该有自己的菜单和额外的选项。我遇到的问题是，成功登录后没有调用 displayMenu() 或 displayMenu_Admin()。有一个名为“user.txt”的文本文件，其中保存了用户名和密码。

#The user should be prompted to enter a username and
#password. A list of valid usernames and passwords are stored in "user.txt".
#Display an appropriate error message if the
#user enters a username that is not listed in user.txt or enters a valid
#username but not a valid password. The user should repeatedly be
#asked to enter a valid username and password until they provide
#appropriate credentials.

def login():
        username = input("Please enter your username?:\n")
        password = input("Please enter your password?:\n")

        for line in open("user.txt","r").readlines():
                field = line.strip().split(",")
                if username == field[0] and password == field[1]:
                        print("Hello " + username + ", welcome back!\n")
                        return True
        if field[0] == "admin":
                displayMenu_Admin()
        else:
                displayMenu()
        print("Username or Password Incorrect\n")
        return False
login()

def displayMenu_Admin():
        global menu_input

        menu_input = input("Please enter one of the following options:\n r - register user\n a - add task\n va- view all tasks\n vm - view my tasks\n s - statistics\n e - exit\n")

        if menu_input == "r":
                register()
        elif menu_input == "a":
                add_task()
        elif menu_input == "va":
                view_all()
        elif menu_input == "vm":
                view_more()
        elif menu_input == "s":
                statistic() 
        elif menu_input == "e":
                exit()

        return menu_input

#A menu should be displayed once the user has successfully logged in.

def displayMenu():
        global menu_input

        menu_input = input("Please enter one of the following options:\n a - add task\n va- view all tasks\n vm - view my tasks\n e - exit\n")

        if menu_input == "a":
                add_task()
        elif menu_input == "va":
                view_all()
        elif menu_input == "vm":
                view_more()
        elif menu_input == "e":
                exit()

        return menu_input

这个想法是用户应该登录，如果用户是“管理员”用户，则应该显示另一个菜单。任何建议或帮助将不胜感激！

标签： pythonfunctionauthenticationmenu

Answer 1

您的问题是，如果登录成功，您将返回，因此调用显示函数的块永远不会执行。

def login():
        username = input("Please enter your username?:\n")
        password = input("Please enter your password?:\n")

        for line in open("user.txt","r").readlines():
                field = line.strip().split(",")
                if username == field[0] and password == field[1]:
                        print("Hello " + username + ", welcome back!\n")
                        return True # <-- this is causing your problems
        if field[0] == "admin":
                displayMenu_Admin()
        else:
                displayMenu()
        print("Username or Password Incorrect\n")
        return False

要解决您的问题，请在显示菜单后返回

def login():
        username = input("Please enter your username?:\n")
        password = input("Please enter your password?:\n")

        for line in open("user.txt","r").readlines():
                field = line.strip().split(",")
                if username == field[0] and password == field[1]:
                        print("Hello " + username + ", welcome back!\n")

                        if field[0] == "admin":
                            displayMenu_Admin()
                        else:
                            displayMenu()
                        return True
        print("Username or Password Incorrect\n")
        return False

然而，它可能是一个更好的设计，而不是返回一个元组并让其他人处理菜单内容，例如：

def login():
        username = input("Please enter your username?:\n")
        password = input("Please enter your password?:\n")

        for line in open("user.txt","r").readlines():
                field = line.strip().split(",")
                if username == field[0] and password == field[1]:
                        print("Hello " + username + ", welcome back!\n")
                        return True, field[0]== "admin"

        return False, False

login_success, is_admin = login()

if login_success and is_admin:
   displayMenu_Admin()
elif login_success:
   displayMenu()
else:
   print("Username or Password Incorrect\n")