简单的贪食蛇

import java.awt.Button;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.LinkedList;
import java.util.Random;

import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;

public class HungrySnake extends JPanel implements Runnable {

class Point {
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + getOuterType().hashCode();
result = prime * result + x;
result = prime * result + y;
return result;
}

@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Point other = (Point) obj;
if (!getOuterType().equals(other.getOuterType()))
return false;
if (x != other.x)
return false;
if (y != other.y)
return false;
return true;
}

int x;
int y;

public Point(int x, int y) {
this.x = x;
this.y = y;
}

private HungrySnake getOuterType() {
return HungrySnake.this;
}
}

Button[][] buttonArray = new Button[20][20];

LinkedList<Point> snake = new LinkedList<Point>();

Direction currentDirection = Direction.up;
boolean pause = true;

Point food = new Point(8,;

private void init() {
GridLayout gl = new GridLayout(20, 20);
this.setLayout(gl);
for (int i = 0; i < buttonArray.length; i++) {
for (int j = 0; j < buttonArray[i].length; j++) {
Button bt = new Button();
bt.setEnabled(false);
buttonArray[i][j] = bt;
bt.setLabel(i + "" + j);
bt.setBackground(Color.BLUE);
this.add(bt);
}
}

snake.add(new Point(5, 5));

this.setVisible(true);
this.setBackground(Color.gray);
}

public void setPause(boolean b) {
pause = b;
}

public Direction getDirection() {
return currentDirection;
}

public void setDirection(Direction d) {
currentDirection = d;
}

public HungrySnake() {
init();
}

public enum Direction {
up, down, right, left;
}

private void paintSnake() {
for (int i = 0; i < buttonArray.length; i++) {
for (int j = 0; j < buttonArray[i].length; j++) {
buttonArray[i][j].setBackground(Color.gray);
}
}
for (Point snakePoint : snake) {
buttonArray[snakePoint.x][snakePoint.y].setBackground(Color.WHITE);
}
buttonArray[food.x][food.y].setBackground(Color.ORANGE);
}

public void restart() {
snake.clear();
snake.add(new Point(5, 5));
currentDirection = Direction.up;
food = new Point(8,;
paintSnake();
pause = true;
}

private void moveSnake() {
Point first = snake.getFirst();
// Point last = snake.getLast();
Point newPoint = new Point(first.x, first.y);
if (currentDirection == Direction.up) {
newPoint.x = first.x - 1;
}
if (currentDirection == Direction.down) {
newPoint.x = first.x + 1;
}
if (currentDirection == Direction.left) {
newPoint.y = first.y - 1;
}
if (currentDirection == Direction.right) {
newPoint.y = first.y + 1;
}
// out of field or touch itself
if (newPoint.x < 0 || newPoint.x > buttonArray.length || newPoint.y < 0 || newPoint.y > buttonArray.length  || snake.contains(newPoint)) {
JOptionPane.showMessageDialog(this.getParent(), "总共吃了"+(snake.size()-1)+"个食物，"+"任务失败，重新开始！", "Failed", JOptionPane.ERROR_MESSAGE);
restart();
}
else {
// eat food
if (newPoint.x == food.x && newPoint.y == food.y) {
eatFood();
}
// only move
else {
snake.removeLast();
snake.addFirst(newPoint);
}
paintSnake();
}

}

private void eatFood() {
snake.addFirst(food);
genFood();
}

private void genFood() {
while (true) {
Random random = new Random();
int x = random.nextInt(9);
int y = random.nextInt(9);
Point genPoint = new Point(x, y);
if (snake.contains(genPoint)) {
continue;
} else {
food = genPoint;
break;
}
}

}

public void run() {
paintSnake();
while (true) {
if (pause == false) {
moveSnake();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}

public static void main(String[] args) {
JFrame frame = new JFrame();

final HungrySnake hs = new HungrySnake();

frame.add(hs);
frame.setTitle("Hungry Snake");
frame.setBounds(100, 100, 800, 800);
frame.addKeyListener(new KeyListener() {

@Override
public void keyTyped(KeyEvent e) {

}

@Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_UP) {
if(hs.getDirection() != Direction.down)
hs.setDirection(Direction.up);
}
if (e.getKeyCode() == KeyEvent.VK_DOWN) {
if(hs.getDirection() != Direction.up)
hs.setDirection(Direction.down);
}
if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
if(hs.getDirection() != Direction.left)
hs.setDirection(Direction.right);
}
if (e.getKeyCode() == KeyEvent.VK_LEFT) {
if(hs.getDirection() != Direction.right)
hs.setDirection(Direction.left);
}

if (e.getKeyCode() == KeyEvent.VK_SPACE) {
hs.setPause(!hs.pause);
}
}

@Override
public void keyReleased(KeyEvent e) {

}

});
frame.show();
JOptionPane.showMessageDialog(frame, "按空格键开始或暂停。游戏规则很简单，不能碰边，不能碰自己，用方向键控制蛇前进方向。", "Start",JOptionPane.INFORMATION_MESSAGE);
Thread t = new Thread(hs);
t.start();

}

}