Java

Question

我编程的时间不长，我花了几个小时试图让这个方法做我需要的事情，所以在这一点上非常感谢帮助。我正在创建一个棋盘游戏，提示玩家输入玩家数量，然后依次提示他们输入他们的名字，然后将创建这些新玩家和他们的名字 set/stored。我还想确保两个玩家不能重名。

这是我播放器的一部分class:

public class Player {

private String name;
        private int currentPosition;
        private int distance;
        private boolean quit;
        


public Player() {

        }

        public Player(String name, int currentPosition, int distance, boolean quit) {
            this.name = name;
            this.currentPosition = currentPosition;
            this.distance = distance;
            this.quit = quit;
        }


        public String getName() {
            return name;
        }


        public void setName(String name) {
            this.name = name;
        }

}

我有一个 setNumberOfPlayers 方法，它运行良好，并且在调用 getNumberOfPlayers() 时获得正确的玩家数量。

public class SetUpGame {

Scanner sc = new Scanner(System.in);

public void addPlayers() {

        String playerName;
        ArrayList<Player> players = new ArrayList<Player>();

        System.out.println("What are the names of the " + this.numberOfPlayers + " players?\n");

        for (int loop = 1; loop <= getNumberOfPlayers(); loop++) {

            System.out.println("Player " + loop + " please enter your name");
            boolean valid = false;

            do {
                playerName = sc.nextLine();
                Player player = new Player();

                for (Player play : players) {
                    if (players.isEmpty() || !play.getName().equalsIgnoreCase(playerName)) {
                        player.setName(playerName);
                        players.add(player);
                        System.out.println("success, your name is: " +playerName);
                        valid = true;
                    } else {
                        System.out.println("please enter another name");
                        valid = false;
                    }
                }

            } while (valid == false);
        }

        sc.close();
    }

当从 main 调用添加播放器方法时，它给出以下输出：

What are the names of the 2 players?

Player 1 please enter your name

...并且用户可以输入他们的名字，但扫描仪永远不会关闭或循环询问下一个玩家的名字。我把代码搞得一团糟，以至于此时我自己都感到困惑。任何人都可以帮助解决这个问题，以及如何 validate/check 创建玩家并设置他们的名字？谢谢

Answer 1

您的内部 for 循环正在遍历 players 数组，但它是空的。

也许试试这个：

       do {
            System.out.println("Please enter name:");
            playerName = sc.nextLine();
            if(playerName.length()!=0){
                valid = true;
                for(Player play : players)
                  if(play.getName().equalsIgnoreCase(playerName))
                     valid = false;       
                
                if(valid){
                   Player player = new Player();
                   player.setName(playerName);
                   players.add(player);
                }
            }
        } while (!valid);

我认为您可能很难调试，因为您所有的变量名都非常相似。 ('players','player','play')

编辑：已更新以检查是否重复

Answer 2

您在播放器中遗漏了一些 getter 和 setter class。

Player.java

public class Player {

private String name;
    private int currentPosition;
    private double distance;
    private boolean quit;
        
    public Player() {
        // no-args constructor
    }

    public Player(String name, int currentPosition, double distance, boolean quit) {
        this.name = name;
        this.currentPosition = currentPosition;
        this.distance = distance;
        this.quit = quit;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
    public int getCurrentPosition() {
        return currentPosition;
    }

    public void setCurrentPosition(int currentPosition) {
        this.currentPosition = currentPosition;
    }

    public double getDistance() {
        return distance;
    }

    public void setDistance(double distance) {
        this.distance = distance;
    }

    public boolean isQuit() {
        return quit;
    }

    public void setQuit(boolean quit) {
        this.quit = quit;
    }
}

您可以按如下方式实现 SetUpGame class。无需创建 do-while 循环。
SetUpGame.java

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

public class SetUpGame {
        Scanner sc = new Scanner(System.in);
        ArrayList<Player> players = new ArrayList<Player>();
        int numberOfPlayers;
        
        public int getNumberOfPlayers() {
            return numberOfPlayers;
        }

        public void setNumberOfPlayers(int numberOfPlayers) {
            this.numberOfPlayers = numberOfPlayers;
        }

        public void addPlayers() {
            System.out.print("Enter number of players: ");
            numberOfPlayers = sc.nextInt();
            
            System.out.println("What are the names of the " + numberOfPlayers + " players?");
            for(int loop = 1; loop <= numberOfPlayers; loop++) {
                Player player = new Player();
                
                System.out.print("Enter name for player " + loop + ": ");
                player.setName(sc.next());
                
                System.out.print("Enter current position for player " + loop + ": ");
                player.setCurrentPosition(sc.nextInt());
                
                System.out.print("Enter distance for player " + loop + ": ");
                player.setDistance(sc.nextDouble());
                
                System.out.print("Enter validity for player " + loop + ": ");
                player.setQuit(sc.nextBoolean());
                
                players.add(player);
            }
            sc.close();
        }
        
        public void displayAllPlayers() {
            System.out.println("Displaying all players...");
            for(Player p : players) {
                System.out.printf("%s %d %f %b", p.getName(), p.getCurrentPosition(), p.getDistance(), p.isQuit());
            }
        }
}

您终于可以测试您的 SetUpGame class。
测试SetUpGame.java

public class TestSetUpGame {
    public static void main(String[] args) {
        SetUpGame game = new SetUpGame();
        game.addPlayers();
        game.displayAllPlayers();
    }
}

Answer 3

首先，球员名单在方法addPlayers中被定义为一个局部变量，所以当这个方法完成时，所有球员数据都丢失了。因此有必要修改此方法以将玩家添加到 SetupGame class 字段或将 return 玩家列表添加到调用方法。后一种方式是一种更简洁的填充播放器列表的功能方式。

接下来，为了高效检测重名，建议创建并使用Set<String> playerNames。

最后，如果 Scanner 在 System.in 上打开，则不能关闭它，因为之后无法输入任何用户输入。

也就是说，addPlayers 的代码可能如下所示：

public List<Player> addPlayers() {
    List<Player> players = new ArrayList<>();
    Set<String> playerNames = new HashSet<>();
    Scanner sc = new Scanner(System.in);

    System.out.println("What are the names of the " + this.numberOfPlayers + " players?\n");

    for (int loop = 1; loop <= this.numberOfPlayers; loop++) {
        while (true) {
            System.out.println("Player " + loop + " please enter your name");
            String playerName = sc.nextLine();

            if (playerNames.add(playerName)) {// Set.add returns true if name was added to it
                Player p = new Player();
                p.setName(playerName);
                players.add(p);
                break; // input new player
            }
        }
    }
    return players;
}

Java - 围绕 for 循环迭代以创建游戏玩家并设置他们的名字

Java - Iterating around for-loop to create players for game and setting their name

oop

for-loop

do-while

java.util.scanner