I can't check for collision

[Lamar Jared]

I have this snake game that almost works. I have three problems:
1. the head and the tail of the snake overlap each other. Meaning, the head is read and the tail(ball) is green. When is runs the head and tail share the same space.
2. the tail doesn't grow each time it eats an apple. It grows whether an apple was eaten or not.
3. when I run into the tail or the sides of the window it doesn't detect collision.

  public class Board extends JPanel implements ActionListener {
 
private final int WIDTH = 300;
private final int HEIGTH = 300;
private final int DOT_SIZE = 10;
private final int ALL_DOTS = 900;
private final int RAND_POS = 29;
private final int DELAY = 140;
 
private int x[] = new int[ALL_DOTS];
private int y[] = new int[ALL_DOTS];
 
private int dots;
private int apple_x;
private int apple_y;
 
private boolean left = false;
private boolean right = true;
private boolean up = false;
private boolean down = false;
private boolean inGame = true;
 
private Timer timer;
private Shape apple;
private Shape head;
private Shape ball;
 
public Board() {
addKeyListener(new TAdapter());
 
setBackground(Color.black);
 
//apple = new Ellipse2D.Double(apple_x, apple_y, 10, 10);
//head = new Ellipse2D.Double(x[0], y[0], 10, 10);
//ball = new Ellipse2D.Double(x[0], y[0], 10, 10);
 
setFocusable(true);
initGame();
}
 
public void initGame() {
 
dots = 3;
 
for (int z = 0; z < dots; z++) {
x[z] = 50 - z * 10;
y[z] = 50;
}
 
locateApple();
 
timer = new Timer(DELAY, this);
timer.start();
}
 
public void paint(Graphics g) {
 
if (inGame) {

apple = new Ellipse2D.Double(apple_x, apple_y, 10, 10);
Graphics2D g2 = (Graphics2D) g;
//g2.draw(apple);
g2.setColor(Color.green);
//g.fillOval(apple_x, apple_y, 10, 10);
g2.fill(apple);
 
for (int z = 0; z < dots; z++) {
if (z == 0) {

head = new Ellipse2D.Double(x[z], y[z], 10, 10);
g2.draw(head);
g2.setColor(Color.red);
//g.fillOval(x[z],y[z],10,10);
g2.fill(head);
} else{

ball = new Ellipse2D.Double(x[z], y[z], 10, 10);
//g2.draw(ball);
g2.setColor(Color.green);
//g.fillOval(x[z],y[z],10,10);
g2.fill(ball);
}
 
Toolkit.getDefaultToolkit().sync();
g.dispose();
}
} else
gameOver(g);
}
 
public void gameOver(Graphics g) {
 
String msg = "Game Over";
Font small = new Font("Helvetica", Font.BOLD, 14);
FontMetrics metr = this.getFontMetrics(small);
 
g.setColor(Color.white);
g.setFont(small);
g.drawString(msg, (WIDTH - metr.stringWidth(msg)) / 2, HEIGHT / 2);
}
 
public void checkApple() {
if ((x[0] == apple_x) && (y[0] == apple_y)) {
dots++;
locateApple();
}
}
 
public void move() {
 
for (int z = dots; z > 0; z--) {
x[z] = x[(z - 1)];
y[z] = y[(z - 1)];
}
 
if (left)
x[0] -= DOT_SIZE;
 
if (right)
x[0] += DOT_SIZE;
 
if (up)
y[0] -= DOT_SIZE;
 
if (down)
y[0] += DOT_SIZE;
}
 
public void checkCollision() {
 
for (int z = dots; z > 0; z--)
if ((z > 4) && x[0] == x[z] && (y[0] == y[z]))
inGame = false;
 
if (y[0] > HEIGTH)
inGame = false;
 
if (y[0] < 0)
inGame = false;
 
if (x[0] > WIDTH)
inGame = false;
 
if (x[0] < 0)
inGame = false;
}
 
public void locateApple() {
int r = (int) (Math.random() * RAND_POS);
apple_x = ((r * DOT_SIZE));
r = (int) (Math.random() * RAND_POS);
apple_y = ((r * DOT_SIZE));
}
 
public void actionPerformed(ActionEvent arg0) {
 
if (inGame) {
checkApple();
checkCollision();
move();
}
 
repaint();
}
 
private class TAdapter extends KeyAdapter {
 
public void keyPressed(KeyEvent e) {
 
int key = e.getKeyCode();
 
if ((key == KeyEvent.VK_LEFT) && (!right)) {
left = true;
up = false;
down = false;
}
 
if ((key == KeyEvent.VK_RIGHT) && (!left)) {
right = true;
up = false;
down = false;
}
 
if ((key == KeyEvent.VK_UP) && (!down)) {
up = true;
right = false;
left = false;
}
 
if ((key == KeyEvent.VK_DOWN) && (!up)) {
down = true;
right = false;
left = false;
}
}
}
}
  

  public class Snake extends JFrame {

public Snake() {

add(new Board());

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(320, 340);
setLocationRelativeTo(null);
setTitle("Snake");

setResizable(false);
setVisible(true);
}

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

[Michael Dunn]

just wanted to point out that this is wrong
public void paint(Graphics g) {

painting in swing is done by overriding paintComponent(..)

[Lamar Jared]

so should I make a call to super in the paint method?

[Lamar Jared]

Thanks Michael. I made the call to super. I don't have the tail trailing me. Collision detection is working now though. I'm sorry if these concerns are trivial but I'm really new to programing and I'm trying to learn for my job
[ December 23, 2008: Message edited by: Lamar Jared ]