用java写一个贪食蛇游戏

以下是一个简单的贪食蛇游戏，使用Java编写。它包括一个游戏循环，可以处理用户输入，更新游戏状态并绘制游戏画面。

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class SnakeGame extends JFrame implements ActionListener {
    
    private static final int WIDTH = 500;
    private static final int HEIGHT = 500;
    private static final int DOT_SIZE = 20;
    private static final int ALL_DOTS = (WIDTH * HEIGHT) / (DOT_SIZE * DOT_SIZE);
    private static final int RAND_POS = WIDTH / DOT_SIZE;
    private static final int DELAY = 100;
    
    private ArrayList<Point> snake;
    private Point food;
    private Timer timer;
    private boolean inGame;
    private boolean leftDirection;
    private boolean rightDirection;
    private boolean upDirection;
    private boolean downDirection;

    public SnakeGame() {
        setTitle("Snake Game");
        setSize(WIDTH, HEIGHT);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setResizable(false);
        setVisible(true);
        addKeyListener(new TAdapter());
        
        snake = new ArrayList<Point>();
        inGame = true;
        leftDirection = false;
        rightDirection = true;
        upDirection = false;
        downDirection = false;
        
        initGame();
    }
    
    public void initGame() {
        snake.clear();
        snake.add(new Point(100, 100));
        snake.add(new Point(80, 100));
        snake.add(new Point(60, 100));
        
        generateFood();
        
        timer = new Timer(DELAY, this);
        timer.start();
    }
    
    public void generateFood() {
        int x = (int) (Math.random() * RAND_POS) * DOT_SIZE;
        int y = (int) (Math.random() * RAND_POS) * DOT_SIZE;
        food = new Point(x, y);
    }
    
    public void checkFood() {
        if (snake.get(0).equals(food)) {
            snake.add(0, new Point(food));
            generateFood();
        }
    }
    
    public void checkCollision() {
        for (int i = 1; i < snake.size(); i++) {
            if (snake.get(0).equals(snake.get(i))) {
                inGame = false;
            }
        }
        
        if (snake.get(0).x < 0 || snake.get(0).x >= WIDTH || 
            snake.get(0).y < 0 || snake.get(0).y >= HEIGHT) {
            inGame = false;
        }
        
        if (!inGame) {
            timer.stop();
        }
    }
    
    public void move() {
        for (int i = snake.size() - 1; i > 0; i--) {
            snake.set(i, new Point(snake.get(i-1)));
        }
        
        if (leftDirection) {
            snake.get(0).x -= DOT_SIZE;
        } else if (rightDirection) {
            snake.get(0).x += DOT_SIZE;
        } else if (upDirection) {
            snake.get(0).y -= DOT_SIZE;
        } else if (downDirection) {
            snake.get(0).y += DOT_SIZE;
        }
    }
    
    public void paint(Graphics g) {
        super.paint(g);
        
        if (inGame) {
            g.setColor(Color.RED);
            g.fillOval(food.x, food.y, DOT_SIZE, DOT_SIZE);
            
            g.setColor(Color.BLACK);
            for (Point p : snake) {
                g.fillOval(p.x, p.y, DOT_SIZE, DOT_SIZE);
            }
            
            Toolkit.getDefaultToolkit().sync();
        } else {
            gameOver(g);
        }
    }
    
    public void gameOver(Graphics g) {
        String msg = "Game Over";
        Font font = new Font("Arial", Font.BOLD, 16);
        FontMetrics metrics = getFontMetrics(font);
        
        g.setColor(Color.BLACK);
        g.setFont(font);
        g.drawString(msg, (WIDTH - metrics.stringWidth(msg)) / 2, HEIGHT / 2);
    }
    
    public void actionPerformed(ActionEvent e) {
        if (inGame) {
            checkFood();
            checkCollision();
            move();
            repaint();
        }
    }
    
    private class TAdapter extends KeyAdapter {
        
        public void keyPressed(KeyEvent e) {
            int key = e.getKeyCode();
            
            if (key == KeyEvent.VK_LEFT && !rightDirection) {
                leftDirection = true;
                upDirection = false;
                downDirection = false;
            } else if (key == KeyEvent.VK_RIGHT && !leftDirection) {
                rightDirection = true;
                upDirection = false;
                downDirection = false;
            } else if (key == KeyEvent.VK_UP && !downDirection) {
                upDirection = true;
                leftDirection = false;
                rightDirection = false;
            } else if (key == KeyEvent.VK_DOWN && !upDirection) {
                downDirection = true;
                leftDirection = false;
                rightDirection = false;
            }
        }
    }
    
    public static void main(String[] args) {
        new SnakeGame();
    }
}

这个游戏使用Java Swing库来处理窗口和绘制。它使用一个ArrayList来跟踪蛇的身体，一个Point来表示食物的位置，以及一些布尔变量来跟踪蛇的方向。游戏循环在ActionListener中实现，并在每个时钟周期中更新游戏状态并重新绘制游戏画面。键盘事件处理程序允许玩家使用箭头键来控制蛇的移动。