Question

import java.util.ArrayList;
import java.util.Scanner;

public class test {

public static void main(String[] args) {

    ArrayList<String> name = new ArrayList<String>();
    ArrayList<String> game = new ArrayList<String>();
    ArrayList<Integer> score = new ArrayList<Integer>();
    ArrayList<Integer> time = new ArrayList<Integer>();

    Scanner scanner = new Scanner(System.in);
    String answer = "yes";

    {
        do {
            System.out.print("Please enter your username: ");
            name.add(scanner.nextLine());
            System.out.println("Please enter the game: ");
            game.add(scanner.nextLine());
            System.out.println("Please Enter Achievement Score: ");
            score.add(scanner.nextInt());
            System.out.println("Please Enter Playtime: ");
            time.add(scanner.nextInt());
            System.out.print("Any letter to continue alternatively type     quit to Quit.");
            answer = scanner.next();
        } while (!answer.equals("quit"));

        if (answer.equals("quit")); //want it to go back to start     another direcotry here
        else {

            System.out.println("Thanks for adding to the database.");
            for (int i = 0; i < name.size(); i++) {
                System.out.print("Username:" +name.get(i)+"\n");
                System.out.print("~~~~~~~~~~~~" +"\n");
                System.out.print("Game:" +game.get(i)+"\t");
                System.out.print("Score:" +score.get(i)+"\n");
                System.out.print("Minutes played:"+time.get(i));
                System.out.println("");
            }
        }
    }
}
}

这个问题是程序在输入Quit时没有退出，但它正在继续并在一行上放两个问题，如下所示。我该如何解决这个问题？

请输入您的用户名：abc123
请输入游戏：
GTA V
请输入成就分数：
1200
请输入播放时间：
120
任何要继续的信件或者退回Quit.Quit
请输入您的用户名：请输入游戏：

Answer 1

问题在于您要比较退出的大写和小写值。您需要将它们设置为相同的大小写类型才能使它们相等并退出程序。

将支票更改为

 while (!answer.toLowerCase().equals("quit"));
    if (answer.toLowerCase().equals("quit"));

这会将您的输入更改为小写，这是您要比较的。

Answer 2

您的退出信息System.out.print("Any letter to continue alternatively type quit to Quit.");表示您需要将quit全部小写字词结尾。

同时将answer = scanner.next();更改为answer = scanner.nextLine();

编辑：由于您没有任何错误控制，您可以考虑以下代码：

do {
        System.out.print("Please enter your username: ");
        name.add(scanner.nextLine());
        System.out.println("Please enter the game: ");
        game.add(scanner.nextLine());
        System.out.println("Please Enter Achievement Score: ");
        score.add(Integer.valueOf(scanner.nextLine()));
        System.out.println("Please Enter Playtime: ");
        time.add(Integer.valueOf(scanner.nextLine()));
        System.out.print("Any letter to continue alternatively type     quit to Quit.");
        answer = scanner.nextLine();
    } while (!answer.equals("quit"));

我将scanner.nextInt()更改为Integer.valueOf(scanner.nextLine())。使用nextLine()可帮助扫描程序在代码进入下一行之前清除所有数据。

Answer 3

除非您没有关闭扫描仪，否则我没有看到任何问题。您可以运行此操作，您可以看到扫描仪已关闭并在退出单词后进入正常执行状态。

import java.util.ArrayList;
import java.util.Scanner;

public class ScannerTest {

    public static void main(String[] args) {

        ArrayList<String> name = new ArrayList<String>();
        ArrayList<String> game = new ArrayList<String>();
        ArrayList<Integer> score = new ArrayList<Integer>();
        ArrayList<Integer> time = new ArrayList<Integer>();

        Scanner scanner = new Scanner(System.in);
        String answer = "yes";

        {
            do {
                System.out.print("Please enter your username: ");
                name.add(scanner.nextLine());
                System.out.println("Please enter the game: ");
                game.add(scanner.nextLine());
                System.out.println("Please Enter Achievement Score: ");
                score.add(scanner.nextInt());
                System.out.println("Please Enter Playtime: ");            
                time.add(scanner.nextInt());
                System.out.print("Any letter to continue alternatively type     quit to Quit.");
                answer = scanner.next();
            } while (!answer.equals("quit"));
            if(answer.equals("quit")){
                System.out.println("you have just quit");
                scanner.close();
            } //want it to go back to start     another direcotry here
            else {

                System.out.println("Thanks for adding to the database.");
                for (int i = 0; i < name.size(); i++) {
                    System.out.print("Username:" +name.get(i)+"\n");
                    System.out.print("~~~~~~~~~~~~" +"\n");
                    System.out.print("Game:" +game.get(i)+"\t");
                    System.out.print("Score:" +score.get(i)+"\n");
                    System.out.print("Minutes played:"+time.get(i));
                    System.out.println("");
                }
            }

            System.out.print("You are done with scanner");

        }

    }
}

Answer 4

我刚试过你的程序，如果你输入＆＃34; quit＆＃34;它就会退出。（全部小写），如命令行说明建议：

System.out.print（＆＃34;任何要继续的字母或者输入Quit退出。＆＃34;）;

如果您希望quit指令不区分大小写，则应替换此行：

} while (!answer.equals("quit"));

用这个：

} while (!answer.equalsIgnoreCase("quit"));

我希望有所帮助！

数组列表扫描程序循环退出功能

4 个答案: