-3

我正在创建一个吃豆人游戏，但遇到了一个我无法弄清楚的异常：

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -11
at p.PacBoard.moveGhosts(PacBoard.java:207)

这就是我的游戏的逻辑所在（我标记了引发异常的行）：

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Event;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.Timer;

public class PacBoard extends JPanel implements ActionListener {

Dimension d;
String s = "Press s to start.";;
Font small = new Font("Helvetica", Font.BOLD, 14);
FontMetrics metr = this.getFontMetrics(small);

Image ii;
Color dotcolor = new Color(192, 192, 0);
Color mazecolor;

boolean ingame = false;
boolean dying = false;

final int blocksize = 24;
final int nrofblocks = 15;
final int scrsize = nrofblocks * blocksize;
final int pacanimdelay = 2;
final int pacmananimcount = 4;
final int maxghosts = 6;
final int pacmanspeed = 6;

int pacanimcount = pacanimdelay;
int pacanimdir = 1;
int pacmananimpos = 0;
int nrofghosts = 4;
int pacsleft, score;
int deathcounter;
int[] dx, dy;
int[] ghostx, ghosty, ghostdx, ghostdy, ghostspeed;

Image ghost;
Image pacman1, pacman2up, pacman2left, pacman2right, pacman2down;
Image pacman3up, pacman3down, pacman3left, pacman3right;
Image pacman4up, pacman4down, pacman4left, pacman4right;

int pacmanx, pacmany, pacmandx, pacmandy;
int reqdx, reqdy, viewdx, viewdy;

final short leveldata[] =
{ 3, 19, 18, 18, 18, 18, 18, 18, 18, 18, 18, 22, 3, 10, 6,
  1, 25, 24, 16, 16, 16, 16, 16, 16, 16, 16, 20, 5, 15, 5,
  1, 0, 0, 17, 16, 16, 16, 16, 16, 16, 16, 20, 9, 10, 12, 
  19, 18, 18, 16, 16, 16, 24, 16, 24, 16, 16, 24, 18, 18, 22,
  17, 16, 16, 16, 16, 28, 0, 21, 0, 17, 20, 0, 17, 16, 20,
  17, 16, 16, 16, 28, 0, 19, 20, 0, 25, 28, 0, 17, 16, 20,
  17, 16, 16, 28, 0, 19, 16, 20, 0, 0, 0, 0, 17, 16, 20,
  17, 16, 20, 0, 27, 16, 16, 16, 18, 18, 22, 0, 17, 16, 20,
  17, 16, 16, 22, 0, 25, 16, 16, 16, 16, 20, 0, 17, 16, 20,
  17, 16, 16, 16, 22, 0, 25, 16, 16, 16, 20, 0, 17, 16, 20,
  17, 16, 16, 16, 16, 22, 0, 17, 16, 16, 20, 0, 17, 16, 20,
  25, 16, 24, 16, 16, 16, 18, 16, 16, 16, 16, 18, 24, 24, 28,
  1, 21, 0, 17, 16, 16, 16, 16, 16, 16, 16, 20, 0, 8, 12,
  9, 29, 0, 17, 16, 16, 16, 16, 16, 16, 16, 20, 0, 10, 14,
  9, 15, 27, 24, 24, 24, 24, 24, 24, 24, 24, 28, 8, 10, 14};

final int validspeeds[] = {1, 2, 3, 4, 5, 6};
final int maxspeed = 6;

int currentspeed = 3;
short[] screendata;
Timer timer;


public PacBoard() {

    GetImages();

    addKeyListener(new TAdapter());

    screendata = new short[nrofblocks * nrofblocks];
    mazecolor = new Color(255, 0, 5);
    setFocusable(true);

    d = new Dimension(400, 400);

    setBackground(Color.black);
    setDoubleBuffered(true);

    ghostx = new int[maxghosts];
    ghostdx = new int[maxghosts];
    ghosty = new int[maxghosts];
    ghostdy = new int[maxghosts];
    ghostspeed = new int[maxghosts];
    dx = new int[4];
    dy = new int[4];
    timer = new Timer(40, this);
    timer.start();
}

public void addNotify() {
    super.addNotify();
    GameInit();
}


public void DoAnim() {
    pacanimcount--;
    if (pacanimcount <= 0) {
        pacanimcount = pacanimdelay;
        pacmananimpos = pacmananimpos + pacanimdir;
        if (pacmananimpos == (pacmananimcount - 1) || pacmananimpos == 0)
            pacanimdir = -pacanimdir;
    }
}


public void PlayGame(Graphics2D g2d) {
    if (dying) {
        Death();
    } else {
        MovePacMan();
        DrawPacMan(g2d);
        moveGhosts(g2d);
        CheckMaze();
    }
}


public void ShowIntroScreen(Graphics2D g2d) {

    g2d.setColor(new Color(0, 32, 48));
    g2d.fillRect(50, scrsize / 2 - 30, scrsize - 100, 50);
    g2d.setColor(Color.white);
    g2d.drawRect(50, scrsize / 2 - 30, scrsize - 100, 50);
    g2d.setColor(Color.white);
    g2d.setFont(small);
    g2d.drawString(s, (scrsize - metr.stringWidth(s)) / 2, scrsize / 2);
}


public void DrawScore(Graphics2D g) {
    int i;
    String s;

    g.setFont(small);
    g.setColor(new Color(96, 128, 255));
    s = "Score: " + score;
    g.drawString(s, scrsize / 2 + 96, scrsize + 16);
    for (i = 0; i < pacsleft; i++) {
        g.drawImage(pacman3left, i * 28 + 8, scrsize + 1, this);
    }
}


public void CheckMaze() {
    short i = 0;
    boolean finished = true;

    while (i < nrofblocks * nrofblocks && finished) {
        if ((screendata[i] & 48) != 0)
            finished = false;
        i++;
    }

    if (finished) {
        score += 50;

        if (nrofghosts < maxghosts)
            nrofghosts++;
        if (currentspeed < maxspeed)
            currentspeed++;
        LevelInit();
    }
}

public void Death() {

    pacsleft--;
    if (pacsleft == 0)
        ingame = false;
    LevelContinue();
}


public void moveGhosts(Graphics2D g2d) {
    short i;
    int pos;
    int count;

    for (i = 0; i < nrofghosts; i++) {
        if (ghostx[i] % blocksize == 0 && ghosty[i] % blocksize == 0) {
            pos = ghostx[i] / blocksize + nrofblocks * (int)(ghosty[i] / blocksize);

            count = 0;
//line that causes problems below
            if ((screendata[pos] & 1) == 0 && ghostdx[i] != 1) {
//line that causes problems above
                dx[count] = -1;
                dy[count] = 0;
                count++;
            }
            if ((screendata[pos] & 2) == 0 && ghostdy[i] != 1) {
                dx[count] = 0;
                dy[count] = -1;
                count++;
            }
            if ((screendata[pos] & 4) == 0 && ghostdx[i] != -1) {
                dx[count] = 1;
                dy[count] = 0;
                count++;
            }
            if ((screendata[pos] & 8) == 0 && ghostdy[i] != -1) {
                dx[count] = 0;
                dy[count] = 1;
                count++;
            }

            if (count == 0) {
                if ((screendata[pos] & 15) == 15) {
                    ghostdx[i] = 0;
                    ghostdy[i] = 0;
                } else {
                    ghostdx[i] = -ghostdx[i];
                    ghostdy[i] = -ghostdy[i];
                }
            } else {
                count = (int)(Math.random() * count);
                if (count > 3)
                    count = 3;
                ghostdx[i] = dx[count];
                ghostdy[i] = dy[count];
            }

        }
        ghostx[i] = ghostx[i] + (ghostdx[i] * ghostspeed[i]);
        ghosty[i] = ghosty[i] + (ghostdy[i] * ghostspeed[i]);
        DrawGhost(g2d, ghostx[i] + 1, ghosty[i] + 1);

        if (pacmanx > (ghostx[i] - 12) && pacmanx < (ghostx[i] + 12) &&
            pacmany > (ghosty[i] - 12) && pacmany < (ghosty[i] + 12) &&
            ingame) {

            dying = true;
            deathcounter = 64;

        }
    }
}


public void DrawGhost(Graphics2D g2d, int x, int y) {
    g2d.drawImage(ghost, x, y, this);
}


public void MovePacMan() {
    int pos;
    short ch;

    if (reqdx == -pacmandx && reqdy == -pacmandy) {
        pacmandx = reqdx;
        pacmandy = reqdy;
        viewdx = pacmandx;
        viewdy = pacmandy;
    }
    if (pacmanx % blocksize == 0 && pacmany % blocksize == 0) {
        pos = pacmanx / blocksize + nrofblocks * (int)(pacmany / blocksize);
        ch = screendata[pos];

        if ((ch & 16) != 0) {
            screendata[pos] = (short)(ch & 15);
            score++;
        }

        if (reqdx != 0 || reqdy != 0) {
            if (!((reqdx == -1 && reqdy == 0 && (ch & 1) != 0) ||
                  (reqdx == 1 && reqdy == 0 && (ch & 4) != 0) ||
                  (reqdx == 0 && reqdy == -1 && (ch & 2) != 0) ||
                  (reqdx == 0 && reqdy == 1 && (ch & 8) != 0))) {
                pacmandx = reqdx;
                pacmandy = reqdy;
                viewdx = pacmandx;
                viewdy = pacmandy;
            }
        }

        // Check for standstill
        if ((pacmandx == -1 && pacmandy == 0 && (ch & 1) != 0) ||
            (pacmandx == 1 && pacmandy == 0 && (ch & 4) != 0) ||
            (pacmandx == 0 && pacmandy == -1 && (ch & 2) != 0) ||
            (pacmandx == 0 && pacmandy == 1 && (ch & 8) != 0)) {
            pacmandx = 0;
            pacmandy = 0;
        }
    }
    pacmanx = pacmanx + pacmanspeed * pacmandx;
    pacmany = pacmany + pacmanspeed * pacmandy;
}


public void DrawPacMan(Graphics2D g2d) {
    if (viewdx == -1)
        DrawPacManLeft(g2d);
    else if (viewdx == 1)
        DrawPacManRight(g2d);
    else if (viewdy == -1)
        DrawPacManUp(g2d);
    else
        DrawPacManDown(g2d);
}

public void DrawPacManUp(Graphics2D g2d) {
    switch (pacmananimpos) {
    case 1:
        g2d.drawImage(pacman2up, pacmanx + 1, pacmany + 1, this);
        break;
    case 2:
        g2d.drawImage(pacman3up, pacmanx + 1, pacmany + 1, this);
        break;
    case 3:
        g2d.drawImage(pacman4up, pacmanx + 1, pacmany + 1, this);
        break;
    default:
        g2d.drawImage(pacman1, pacmanx + 1, pacmany + 1, this);
        break;
    }
}


public void DrawPacManDown(Graphics2D g2d) {
    switch (pacmananimpos) {
    case 1:
        g2d.drawImage(pacman2down, pacmanx + 1, pacmany + 1, this);
        break;
    case 2:
        g2d.drawImage(pacman3down, pacmanx + 1, pacmany + 1, this);
        break;
    case 3:
        g2d.drawImage(pacman4down, pacmanx + 1, pacmany + 1, this);
        break;
    default:
        g2d.drawImage(pacman1, pacmanx + 1, pacmany + 1, this);
        break;
    }
}


public void DrawPacManLeft(Graphics2D g2d) {
    switch (pacmananimpos) {
    case 1:
        g2d.drawImage(pacman2left, pacmanx + 1, pacmany + 1, this);
        break;
    case 2:
        g2d.drawImage(pacman3left, pacmanx + 1, pacmany + 1, this);
        break;
    case 3:
        g2d.drawImage(pacman4left, pacmanx + 1, pacmany + 1, this);
        break;
    default:
        g2d.drawImage(pacman1, pacmanx + 1, pacmany + 1, this);
        break;
    }
}


public void DrawPacManRight(Graphics2D g2d) {
    switch (pacmananimpos) {
    case 1:
        g2d.drawImage(pacman2right, pacmanx + 1, pacmany + 1, this);
        break;
    case 2:
        g2d.drawImage(pacman3right, pacmanx + 1, pacmany + 1, this);
        break;
    case 3:
        g2d.drawImage(pacman4right, pacmanx + 1, pacmany + 1, this);
        break;
    default:
        g2d.drawImage(pacman1, pacmanx + 1, pacmany + 1, this);
        break;
    }
}


public void DrawMaze(Graphics2D g2d) {
    short i = 0;
    int x, y;

    for (y = 0; y < scrsize; y += blocksize) {
        for (x = 0; x < scrsize; x += blocksize) {
            g2d.setColor(mazecolor);
            g2d.setStroke(new BasicStroke(2));

            if ((screendata[i] & 1) != 0) // draws left
            {
                g2d.drawLine(x, y, x, y + blocksize - 1);
            }
            if ((screendata[i] & 2) != 0) // draws top
            {
                g2d.drawLine(x, y, x + blocksize - 1, y);
            }
            if ((screendata[i] & 4) != 0) // draws right
            {
                g2d.drawLine(x + blocksize - 1, y, x + blocksize - 1,
                             y + blocksize - 1);
            }
            if ((screendata[i] & 8) != 0) // draws bottom
            {
                g2d.drawLine(x, y + blocksize - 1, x + blocksize - 1,
                             y + blocksize - 1);
            }
            if ((screendata[i] & 16) != 0) // draws point
            {
                g2d.setColor(dotcolor);
                g2d.fillRect(x + 11, y + 11, 2, 2);
            }
            i++;
        }
    }
}

public void GameInit() {
    pacsleft = 3;
    score = 0;
    LevelInit();
    nrofghosts = 4;
    currentspeed = 3;
}


public void LevelInit() {
    int i;
    for (i = 0; i < nrofblocks * nrofblocks; i++)
        screendata[i] = leveldata[i];

    LevelContinue();
}


public void LevelContinue() {
    short i;
    int dx = 1;
    int random;

    for (i = 0; i < nrofghosts; i++) {
        ghosty[i] = 4 * blocksize;
        ghostx[i] = 4 * blocksize;
        ghostdy[i] = 0;
        ghostdx[i] = dx;
        dx = -dx;
        random = (int)(Math.random() * (currentspeed + 1));
        if (random > currentspeed)
            random = currentspeed;
        ghostspeed[i] = validspeeds[random];
    }

    pacmanx = 7 * blocksize;
    pacmany = 11 * blocksize;
    pacmandx = 0;
    pacmandy = 0;
    reqdx = 0;
    reqdy = 0;
    viewdx = -1;
    viewdy = 0;
    dying = false;
}

public void GetImages()
{

  ghost = new ImageIcon(PacBoard.class.getResource("../pacpix/ghost.gif")).getImage();
  pacman1 = new ImageIcon(PacBoard.class.getResource("../pacpix/pacman.png")).getImage();
  pacman2up = new ImageIcon(PacBoard.class.getResource("../pacpix/up1.png")).getImage();
  pacman3up = new ImageIcon(PacBoard.class.getResource("../pacpix/up2.png")).getImage();
  pacman4up = new ImageIcon(PacBoard.class.getResource("../pacpix/up3.png")).getImage();
  pacman2down = new ImageIcon(PacBoard.class.getResource("../pacpix/down1.png")).getImage();
  pacman3down = new ImageIcon(PacBoard.class.getResource("../pacpix/down2.png")).getImage(); 
  pacman4down = new ImageIcon(PacBoard.class.getResource("../pacpix/down3.png")).getImage();
  pacman2left = new ImageIcon(PacBoard.class.getResource("../pacpix/left1.png")).getImage();
  pacman3left = new ImageIcon(PacBoard.class.getResource("../pacpix/left2.png")).getImage();
  pacman4left = new ImageIcon(PacBoard.class.getResource("../pacpix/left3.png")).getImage();
  pacman2right = new ImageIcon(PacBoard.class.getResource("../pacpix/right1.png")).getImage();
  pacman3right = new ImageIcon(PacBoard.class.getResource("../pacpix/right2.png")).getImage();
  pacman4right = new ImageIcon(PacBoard.class.getResource("../pacpix/right3.png")).getImage();

}

public void paint(Graphics g)
{
  super.paint(g);

  Graphics2D g2d = (Graphics2D) g;

  g2d.setColor(Color.black);
  g2d.fillRect(0, 0, d.width, d.height);

  DrawMaze(g2d);
  DrawScore(g2d);
  DoAnim();
  if (ingame){
    PlayGame(g2d);
  }
  else{
    ShowIntroScreen(g2d);
  }

  g.drawImage(ii, 5, 5, this);
  Toolkit.getDefaultToolkit().sync();
  g.dispose();
}

class TAdapter extends KeyAdapter {
    public void keyPressed(KeyEvent e) {

      int key = e.getKeyCode();

      if (ingame)
      {
        if (key == KeyEvent.VK_LEFT)
        {
          reqdx=-1;
          reqdy=0;
        }
        else if (key == KeyEvent.VK_RIGHT)
        {
          reqdx=1;
          reqdy=0;
        }
        else if (key == KeyEvent.VK_UP)
        {
          reqdx=0;
          reqdy=-1;
        }
        else if (key == KeyEvent.VK_DOWN)
        {
          reqdx=0;
          reqdy=1;
        }
        else if (key == KeyEvent.VK_ESCAPE && timer.isRunning())
        {
          ingame=false;
        }
        else if (key == KeyEvent.VK_PAUSE) {
            if (timer.isRunning())
                timer.stop();
            else timer.start();
        }
      }
      else
      {
        if (key == 's' || key == 'S')
      {
          ingame=true;
          GameInit();
        }
      }
  }

      public void keyReleased(KeyEvent e) {
          int key = e.getKeyCode();

          if (key == Event.LEFT || key == Event.RIGHT || 
             key == Event.UP ||  key == Event.DOWN)
          {
            reqdx=0;
            reqdy=0;
          }
      }
  }

public void actionPerformed(ActionEvent e) {
    repaint();  
}
}

抱歉，我知道代码很多，但我不确定问题出在哪里。这是它被捕获的行：

if ((screendata[pos] & 1) == 0 && ghostdx[i] != 1) {

我知道它必须将数组的大小增加或减少到非法数字，但是在哪里？为什么？这就是我不明白的。哦，我的输出窗口中出现了大约 10 次异常，但不知道为什么。这是否意味着它在我的一个 for 循环中增加了？

感谢任何愿意提供帮助的人，我将根据需要提供更多信息。

编译：

import javax.swing.JFrame;


public class Pacman extends JFrame
{

  public Pacman()
  {
    add(new PacBoard());
    setTitle("Pacman");
    setSize(380, 420);
    setLocationRelativeTo(null);
    setVisible(true);
  }

  public static void main(String[] args) {
        new Pacman();
  }
}
4

2 回答 2

1

我想我知道（在其他评论者的帮助下）您的问题出在哪里：

我们已经推断出 ghostx[i] 是负数，或者 ghosty[i] 是负数。

请注意，您将 dx 设置为 1，然后将 ghostx[i] 设置为 dx。当您将 dx 设置为 dx ( dx = -dx;) 的负数时，问题就出现了。这意味着在下一次迭代中，dx 为负数，因此超出范围。

（越界了，因为pos是根据ghostx[i]计算的，而ghostx[i]是根据dx计算的)

我不确定你想在这里做什么，但一定要改变这条线，看看它是否能解决你的问题。对应该做什么发表评论dx = -dx;，我会帮你弄清楚。

罪魁祸首的代码：

public void LevelContinue() {
    short i;
    int dx = 1;
    int random;

    for (i = 0; i < nrofghosts; i++) {
        ghosty[i] = 4 * blocksize;
        ghostx[i] = 4 * blocksize;
        ghostdy[i] = 0;
        ghostdx[i] = dx;



        dx = -dx;//Line which kills your code



        random = (int)(Math.random() * (currentspeed + 1));
        if (random > currentspeed)
            random = currentspeed;
        ghostspeed[i] = validspeeds[random];
    }

总而言之，我在上面发布的代码（特别是“杀死你的代码的行”）将 ghosty[i] 设置为负值。它只会在奇数索引处执行此操作（ghostx[0] 和 ghostx[2] 将为正数，但 [1]（这是您所说的有问题的索引）将为负数。

稍后，这里有这段代码：

pos = ghostx[i] / blocksize + nrofblocks * (int)(ghosty[i] / blocksize);

在一个部门中使用ghostx[]，导致整个事情变得消极。

然后，在您声明不好的代码行中，使用screendata[pos]，这导致您使用负索引。

编辑：新的答案建议。

现在，到目前为止，我发现修改 ghostx 或 ghosty 的唯一代码行是：

ghostx[i] = ghostx[i] + (ghostdx[i] * ghostspeed[i]);
ghosty[i] = ghosty[i] + (ghostdy[i] * ghostspeed[i]);

和

 ghosty[i] = 4 * blocksize;
 ghostx[i] = 4 * blocksize;

我们知道两者中的后者不可能，因为 blocksize 和 4 都是正数。

这意味着

ghostx[i] = ghostx[i] + (ghostdx[i] * ghostspeed[i]);
ghosty[i] = ghosty[i] + (ghostdy[i] * ghostspeed[i]);

是问题所在。

看着这个，在我看来，你的鬼魂在你的板外游荡！我注意到ghostdx 可以是负数（ghostdx 是ghost delta x 对吗？）这意味着当你的ghost 向负方向行进时，它最终会走得太远以至于它最终会离开棋盘。

在这些行之后，我建议添加这些行：

if (ghostx[i] < 0) ghostx[i] = 0;
if (ghosty[i] < 0) ghosty[i] = 0;
if (ghostx[i] >= WHATEVER_YOUR_MAX_POSITION_IS) ghostx[i] = WHATEVER_YOUR_MAX_POSITION_IS - 1;
if (ghosty[i] >= WHATEVER_YOUR_MAX_POSITION_IS) ghosty[i] = WHATEVER_YOUR_MAX_POSITION_IS - 1;

请看看这是否能解决您的问题！

于 2013-03-19T22:50:19.333 回答
0

pos = pacmanx / blocksize + nrofblocks * (int)(pacmany / blocksize);

确保您的分配值不能> nrofblocks * nrofblocks，还确保您的除数始终> 0，据我记得在java中您可以除以零，但这将导致 NaN ， pos[NaN] 显然超出界限..啊，但我认为这对 int 没有意义，这是你的变量 pos。

我只是提供一些我会先检查的想法，现在处理数字为时已晚，抱歉；）

顺便说一句，为什么不使用向量作为坐标？应该容易得多

于 2013-03-19T22:47:40.217 回答