这个蛇游戏代码。我想在这个游戏中添加系统分数。这样每次蛇吃他的分数都会增加。但是如果蛇没有得到食物分数就不会增加。
如何显示当前分数？
这是 ：
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
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 Board extends JPanel implements ActionListener {
private final int WIDTH = 300;
private final int HEIGHT = 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 Image ball;
private Image apple;
private Image head;
public Board() {
addKeyListener(new TAdapter());
setBackground(Color.black);
ImageIcon iid = new ImageIcon(this.getClass().getResource("dot.png"));
ball = iid.getImage();
ImageIcon iia = new ImageIcon(this.getClass().getResource("apple.png"));
apple = iia.getImage();
ImageIcon iih = new ImageIcon(this.getClass().getResource("head.png"));
head = iih.getImage();
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) {
super.paint(g);
if (inGame) {
g.drawImage(apple, apple_x, apple_y, this);
for (int z = 0; z < dots; z++) {
if (z == 0)
g.drawImage(head, x[z], y[z], this);
else g.drawImage(ball, x[z], y[z], this);
}
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] > HEIGHT) {
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 e) {
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;
}
}
}