我正在创建一个吃豆人游戏，我得到一个异常，我无法弄清楚:
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -11
at p.PacBoard.moveGhosts(PacBoard.java:207)
这里是我的游戏逻辑所在的地方(我标记了抛出异常的行):
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();
}
}
对不起，我知道这是很多代码，但我不确定问题是在哪里创建的。下面是它被捕获的行:
if ((screendata[pos] & 1) == 0 && ghostdx[i] != 1) {
我知道它必须增加或减少数组的大小到一个非法的数字，但是在哪里?,为什么?这就是我不明白的地方。哦，我得到了异常在我的输出窗口大约10次，不知道为什么，虽然。这是否意味着它在一个for循环中增加了?
感谢任何帮助我的人，我将根据需要提供更多的信息。
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();
}
}
我想我知道(在其他评论者的帮助下)你的问题在哪里:
我们已经推导出ghostx[i]是负的，或者ghosty[i]是负的。
注意这里设置dx为1，然后设置ghostx[i]为dx。当你设dx为- dx (dx = -dx;)时问题就出现了这意味着在下一次迭代中，dx是负的，因此超出了边界。
(越界，因为pos是基于ghostx[i]计算的。ghostx[i]是根据dx计算的。如果dx是负的，那么ghostx[i]也是负的，pos也是负的，这会造成很大的问题)
我不知道你在这里想做什么，但一定要改变这一行，看看它是否解决了你的问题。给dx = -dx;应该做什么留下评论，我会帮你弄清楚的。
错误代码:
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，我上面发布的代码(特别是"杀死你的代码的行")将ghost [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，但[1](即您声明存在问题的索引)将为负。
下面这段代码:
pos = ghostx[i] / blocksize + nrofblocks * (int)(ghosty[i] / blocksize);
在除法中使用ghostx[]，使得整个数变成负数。
然后，在您声明为坏的代码行使用screendata[pos]，这导致您使用负索引。
编辑:新的答案建议。
现在，我发现到目前为止修改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;
我们知道后者不可能是正确的，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。
看着这个，在我看来，你的鬼魂在你的板外游荡!我注意到ghostdx可以是负的(ghostdx是鬼x，对吧?)这意味着当你的幽灵向负方向移动时，它最终会走得太远，最终会走到板子外面。
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;
看看这是否能解决你的问题!
pos = pacmanx/blocksize + nrofblocks * (int)(pacmany/blocksize);
确保你的赋值不能是> nrofblocks*nrofblocks，还要确保你的除数总是> 0，据我所知，在java中你可以除以零，但这将导致NaN, pos[NaN]显然是越界的。啊，但我认为这对int没有意义，它是你的变量pos。
我只是提供一些想法，我要先检查一下，现在处理数字太晚了，抱歉;)
顺便说一句，为什么不用向量作为坐标呢?应该会容易得多