Question

当用户尝试登录并输入一个不存在的用户名以及密码时，我希望名为exist_user的方法继续显示登录菜单（login_screen_selection）。问题是一旦菜单再次出现并且用户输入“ 1”（提示他们再次输入用户名），程序就会终止。我希望该方法的行为像一个无限循环，只有在您输入已经存在的用户名时才会中断

def process_login
  case login_screen_selection
  when '1'
    existing_user
  when '2'
    create_account
  when '3'
    exit_application
  else
    process_login
  end
end

def login_screen_selection
  puts "1. Login"
  puts "2. Create account"
  puts "3. Exit"
  gets.chomp
end

def existing_user
  puts "Please Enter Username"
  get_username = gets.chomp

  puts "Please Enter Password"
  get_password = gets.chomp

  customer = Customer.find_by(
    username: get_username,
    password: get_password
    )

  if customer.nil? do
    puts 'Sorry, username and/or password combination not valid. Please try again'
    login_screen_selection 
    break if !customer.nil?
  end
end

Answer 1

看起来有些不错的答案。我只补充说，如果您执行以下操作，则无需检查if customer.nil?或if customer或其变体：

def existing_user
  puts "Please Enter Username"
  username = gets.chomp

  puts "Please Enter Password"
  password = gets.chomp

  unless customer = Customer.find_by(
                      username: username,
                      password: password
                    )
    puts 'Sorry, username and/or password combination not valid. Please try again'
    process_login
  end
end

Answer 2

您想要一个循环，所以写一个循环：

   def existing_user
     while customer.nil? do
       puts "Please Enter Username"
       get_username = gets.chomp

       puts "Please Enter Password"
       get_password = gets.chomp

      customer = Customer.find_by(
        username: get_username,
        password: get_password
      )

      if customer.nil? do
        puts 'Sorry, username and/or password combination not valid. Please try again'
     end
   end

Answer 3

只有一个错误会阻止您离开那里，在existing_user函数中，您应该调用process_login以外的login_screen_selection。 login_screen_selection仅发出一条消息并等待输入，如果收到输入，则程序结束。

def existing_user
  puts "Please Enter Username"
  get_username = gets.chomp

  puts "Please Enter Password"
  get_password = gets.chomp

  customer = Customer.find_by(
    username: get_username,
    password: get_password
    )

  if customer.nil? do
    puts 'Sorry, username and/or password combination not valid. Please try again'
    process_login
  end
end

Answer 4

您可以进入循环。您将一直在那里直到找到客户。如果是这样，程序将继续运行，并显示菜单。

def existing_user
  loop do
    puts "Please Enter Username"
    get_username = gets.chomp

    puts "Please Enter Password"
    get_password = gets.chomp

    customer = Customer.find_by(
      username: get_username,
      password: get_password
    )

    break if customer

    puts 'Sorry, username and/or password combination not valid. Please try again'
  end

  login_screen_selection
end

无限循环活动记录

4 个答案: