Question

public static void sendMessage(String sender){
    Scanner scTwo = new Scanner(System.in);

    System.out.println("Enter your recipient: ");
    String recipient = scTwo.next();
    System.out.println("Enter your message: ");
    String message = scTwo.next();

    Message myMessage = new Message(sender, message);


}

public static void readMessage(Mailbox myMail){
    for (int x = 0; x < myMail.getMail().size(); x++){
        System.out.println("Email Number: " + x + " from " + myMail.getMail().get(x).getSender());
        System.out.println("Message: " + myMail.getMail().get(x).getText()); 
    }
}       


public static void readUserName(String userName){
        ArrayList<Mailbox> users = new ArrayList<Mailbox>();
        for(int x = 0; x < users.size(); x++){
            if (userName.equals(users.get(x))){
                System.out.println("Hello " + userName + ".");
            } else {
                users.add(new Mailbox(userName));
                System.out.println("Hello " + userName + ", welcome.");
            }
        }   
}



public static void main(String[] args) {
            boolean emailOn = true;
    boolean done = false;

            Scanner sc = new Scanner(System.in);

            while (emailOn){
                while(!done){       
                    System.out.println("Enter username (-1 to quit): ");

                    if (sc.hasNextInt()){
                        String userName = sc.next();
                        readUserName(userName);

                        System.out.println("Your Options ");    
                        System.out.println("(1) Read your email");
                        System.out.println("(2) Send an email");
                        System.out.println("(3) Log out of Email");
                        int number = sc.nextInt();

                        switch(number){     
                        case 1 : readMessage(userName); break;
                        case 2 : sendMessage(userName); break;
                        case 3 : done = true; break;
                        }
                        //sc.next() = new Mailbox();
                    }       
                }
                System.out.println("Logged out, have a nice day now!");
                System.out.println("Enter \"-1\" to turn off.");

                if(sc.nextInt() == -1){
                    emailOn = false;
                } else {
                    emailOn = false;
                }

            }// ArrayList<Mailbox> mailboxes
            System.out.println("Goodbye");
}


class Mailbox{
private ArrayList<Message> mail;
private String userNameTaken;

public Mailbox(String aUserName){
    userNameTaken = aUserName;
}

public String getUserName(){
    return userNameTaken;
}

public void addMessage(Message aMessage){
            mail.add(aMessage);
}

public ArrayList<Message> getMail(){
    return mail;

}



class Message{
private String sender;
private String text;

public Message(String aSender, String messageBody){
    sender = aSender;
    text = messageBody;
}

public String getText(){
    return text;
}
public String getSender(){
    return sender;
}

在案例1中我试图调用readMessage但是因为它是无效的，所以它将无效。我不确定如何解决这个问题。我是新手首先为用户调用ArrayList，然后调用消息来打印它们吗？我在readUserName中做了myitil的myitil。但是我无法将字符串转换为邮箱，因此readMessage（用户名）不适用。

Answer 1

使用一个参数参数调用您的方法，

case 1 : readMessage(myMail); break;

注意：在此之前，您应该声明并保留myMail作为您想要的内容

切换语句调用void类

1 个答案: