java - 在 init 之外的 java 中创建对象

Question

所以对于我正在创建的游戏，我有几个扩展 GameDriver 的类。

到目前为止，我已经能够在所有其他类上扩展 GameDriver，然后在 GameDriver 中我可以:

ArrayList<Card>  library = new ArrayList<Card>();

今天我开始学习 GameAI 类并扩展了 GameDriver，当我输入时:

GameAI Enemy = new GameAI();

在同一位置我放置了另一行代码(在公共(public)类 GameDriver 的正下方)

我得到:

java.lang.StackOverflowError
at java.util.WeakHashMap.expungeStaleEntries(Unknown Source)
at java.util.WeakHashMap.getTable(Unknown Source)
at java.util.WeakHashMap.get(Unknown Source)
at java.awt.Component.checkCoalescing(Unknown Source)
at java.awt.Component.<init>(Unknown Source)
at java.awt.Container.<init>(Unknown Source)
at java.awt.Panel.<init>(Unknown Source)
at java.awt.Panel.<init>(Unknown Source)
at java.applet.Applet.<init>(Unknown Source)
at GameDriver.<init>(GameDriver.java:14)
at GameAI.<init>(GameAI.java:8)
at GameDriver.<init>(GameDriver.java:40)
at GameAI.<init>(GameAI.java:8)

如果我把它放在我的小程序的 public void init() 中，那么它不会在运行时给出错误，但是我将无法从我的其他方法访问它，我是不是在看东西？通宵达旦通常对我的大脑没有帮助...

这是 GameAI 目前的样子:

public class GameAI extends GameDriver {

    public int life;
    public int energy;

    public void drawPhase(){

    }

    public GameAI(){
        life = 20;
        energy = 2;
    }
}

然后是 GameDriver 的一些部分:

public class GameDriver extends Applet implements MouseMotionListener,MouseListener {

Graphics g; 
Image offscreen;
Dimension dim; 

int playerLife = 20;
int playerEnergy = 8;

int xMouse; 
int yMouse;
int lineThickness = 4;
int handSize = 6;
int currentHover;
boolean slotHover;
int currentSelected;
boolean slotClicked;
int currentHoverBoard;
boolean slotHoverBoard;
boolean slotClickedBoard;
int currentSelectedBoard;

boolean canPlace;
ArrayList<Card>  library = new ArrayList<Card>();
ArrayList<Card>  hand = new ArrayList<Card>();
ArrayList<Card>  playerBoard = new ArrayList<Card>();
GameAI Enemy;
int[] handBoxX = new int[handSize];
int[] handBoxY = new int[handSize];
int[] handBoxW = new int[handSize];
int[] handBoxH = new int[handSize];

int[] playerBoardX = new int[8];
int[] playerBoardY = new int[8];
int[] playerBoardW = new int[8];
int[] playerBoardH = new int[8];



public void init(){
    this.setSize(640, 480);
    dim = this.getSize();
    addMouseMotionListener(this);
    addMouseListener(this);
    createLibrary();
    drawFirstHand();
    printHand();


    GameAI Enemy = new GameAI();
    checkEnemy();



    offscreen = createImage(this.getSize().width,this.getSize().height);
    g = offscreen.getGraphics(); 
}

public void checkEnemy(){
    System.out.println(Enemy.energy);
}

... Alot more methods and stuff below, but nothing to do with the GameAI enemy

Answer 1

您正在 GameDriver 中创建一个 GameAI 对象，它扩展了该类。这将导致递归继续，直到你用完内存。

解决方案:不要这样做。您的 GameAI 类不应扩展 GameDriver，因为这是共享信息的错误方式，即使您没有这种递归噩梦，它也根本无法工作。而是给 GameAI 一个 GameDriver 字段，并通过其构造函数将 GameDriver 实例传递给 GameAI。

即，

class GameAI {
   private GameDriver gameDriver;

   public GameAI(GameDriver gameDriver) {
      this.gameDriver = gameDriver;
   }

   //.... more code
}  

编辑2
如果你想要一个 GameAI 对象，你会这样做

GameAI gameAi = new GameAI(this);

如果你想要一个数组或它们的列表，你可以在循环中执行此操作。