在init之外的java中创建一个Object(Creating an Object in java outside of the init)

 所以对于我正在创建的游戏，我有一些扩展GameDriver的类。 
 
 到目前为止，在所有其他课程中，我已经能够扩展GameDriver，然后在GameDriver中，我可以做到： 
 
ArrayList<Card>  library = new ArrayList<Card>();
 
 今天我开始使用GameAI课程，并扩展了GameDriver，当我放入时： 
 
GameAI Enemy = new GameAI();
 
 在同一个地方，我把另一行代码（在公共类GameDriver下面） 
 
 我明白了： 
 
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applet的public void init（）中，那么它在运行时不会出错，但是后来我无法从其他方法访问它，我在看什么？ 所有的打火机通常都无法帮助我的大脑...... 
 
 这就是GameAI现在的样子： 
 
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

so for the game I'm creating I have a few classes that extend GameDriver.
 
Up until this point, on all the other classes I've been able to extend GameDriver and then In GameDriver I can do:
 
ArrayList<Card>  library = new ArrayList<Card>();
 
Today I started on the GameAI class and I extended GameDriver, and when I put:
 
GameAI Enemy = new GameAI();
 
In the same spot I put the other line of code (Right below public class GameDriver)
 
I get:
 
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)
 
If I put it in the public void init() of my applet, then it doesn't give an error on run, but then I wouldn't be able to access it from my other methods, am I over looking something? All nighters normally don't help my brain...
 
This is what the GameAI looks like as of right now:
 
public class GameAI extends GameDriver {

    public int life;
    public int energy;

    public void drawPhase(){

    }

    public GameAI(){
        life = 20;
        energy = 2;
    }
}
 
And then some bits of the GameDriver:
 
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

原文：https://stackoverflow.com/questions/12027435