Question

因此，我正在制作基于控制台的游戏。

但是我不能理解这一点，或者为什么这样做是错误的。

所以基本上我有10个房间所以房间里有以下东西：

-房间号

-包含“房间”作为值和“字符串”作为键的哈希图

现在问题出了，一个房间可以从北，东，南，西四个方向退出，这就是哈希图中的字符串/键它还可以有2个出口或1或3。因此，在该哈希图中，我将方向另存为键，将另一个房间对象的值另存为值，这样我就可以跟踪到出口为止。所以我有一种添加出口的方法。看起来像这样：代码

public class Room {
    private int RoomNo;
    private HashMap<String, Room> Exits;

    public Room(int roomNo){
        Exits = new HashMap<String, Room>();
        this.RoomNo = roomNo;

    }

    public void Addexits(Room room, String exitDirection){
            Exits.put(exitDirection,room);
    }

与之相比，在游戏类中，我创建了10个房间并使用addexits方法调用添加出口，如下所示：

Rooms = new ArrayList<Room>();
     //initialize all rooms
     room1 = new Room(1);
     room1.Addexits(room4,"West");
     room1.Addexits(room3,"East");
     room2 = new Room(2);
     room2.Addexits(room2,"North");
     room2.Addexits(room2,"South");
     room3 = new Room(3);
     room3.Addexits(room3,"West");
     room3.Addexits(room3,"East");
     room4 = new Room(4);
     room4.Addexits(room4,"West");
     room4.Addexits(room4,"East");

但是，正如您在room1中看到的那样，我尝试将2个出口1在西侧添加到room4，将1个东部在1号出口添加到room3，但是当我运行它时，它将在哈希图中显示：西->空东->空

但是当我添加2个都与对象room1一起退出时，它说应该像这样：

西->房间1 东-> room1

所以我并没有真正弄错我在做错什么，每个房间在创建时都有自己的哈希图，并且房间已经创建好了，所以不应该成为问题。

Answer 1

首先初始化所有房间，然后添加出口；

 room1 = new Room(1);
 room2 = new Room(2);
 room3 = new Room(3);
 room4 = new Room(4);
 room1.Addexits(room4,"West");
 room1.Addexits(room3,"East");
 room2.Addexits(room2,"North");
 room2.Addexits(room2,"South");
 room3.Addexits(room3,"West");
 room3.Addexits(room3,"East");
 room4.Addexits(room4,"West");
 room4.Addexits(room4,"East");

Answer 2

在下面的代码中

Rooms = new ArrayList<Room>();
 //initialize all rooms
 room1 = new Room(1);
 room1.Addexits(room4,"West");
 room1.Addexits(room3,"East");

您要添加尚未初始化的room3和room4。您刚刚声明了它。那就是为什么你得到空的原因。初始化后，尝试添加它。

Rooms = new ArrayList<Room>();
 //initialize all rooms
 room1 = new Room(1);
 room2 = new Room(2);
 room2.Addexits(room2,"North");
 room2.Addexits(room2,"South");
 room3 = new Room(3);
 room3.Addexits(room3,"West");
 room3.Addexits(room3,"East");
 room4 = new Room(4);
 room4.Addexits(room4,"West");
 room4.Addexits(room4,"East");
 //here you add room4 and room3 exits
 room1.Addexits(room4,"West");
 room1.Addexits(room3,"East");

Answer 3

这是因为，当您调用Addexits（）时，不能保证您要添加的房间已经存在。因此，切换您的语句应该可以解决此问题。

Rooms = new ArrayList<Room>();
//initialize all rooms
room1 = new Room(1);
room2 = new Room(2);
room3 = new Room(3);
room4 = new Room(4);

// add all exits
room1.Addexits(room4,"West");
room1.Addexits(room3,"East");

room2.Addexits(room2,"North");
room2.Addexits(room2,"South");

room3.Addexits(room3,"West");
room3.Addexits(room3,"East");

room4.Addexits(room4,"West");
room4.Addexits(room4,"East");

还请注意，您正在将room3作为房间3的出口添加，与房间2和4相同。我不知道这是否是意图。

无法将对象放入连接到其他对象的哈希图中

3 个答案: