java小游戏代码贪吃蛇

Java贪吃蛇是一种基于Java编写的小游戏，玩家通过控制蛇的移动，吃掉食物来增加分数，同时要注意避免蛇头碰到墙壁或者蛇身，否则游戏结束。下面是Java贪吃蛇的代码实现：

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

public class Snake extends JPanel implements ActionListener{
    private int width = 300;
    private int height = 300;
    private int unitSize = 10;
    private int units = (width*height)/unitSize;
    private int delay = 100;
    private int x[] = new int[units];
    private int y[] = new int[units];
    private int bodyParts = 6;
    private int applesEaten = 0;
    private int appleX;
    private int appleY;
    private char direction = 'R';
    private boolean running = false;
    private Timer timer;
    private Random random;

    public Snake(){
        random = new Random();
        this.setPreferredSize(new Dimension(width, height));
        this.setBackground(Color.black);
        this.setFocusable(true);
        this.addKeyListener(new MyKeyAdapter());
        startGame();
    }

    public void startGame(){
        newApple();
        running = true;
        timer = new Timer(delay, this);
        timer.start();
    }

    public void paintComponent(Graphics g){
        super.paintComponent(g);
        draw(g);
    }

    public void draw(Graphics g){
        if(running){
            g.setColor(Color.red);
            g.fillOval(appleX, appleY, unitSize, unitSize);

            for(int i=0; i<bodyParts; i++){
                if(i==0){
                    g.setColor(Color.green);
                }else{
                    g.setColor(new Color(45,180,0));
                }
                g.fillRect(x[i], y[i], unitSize, unitSize);
            }

            g.setColor(Color.red);
            g.setFont(new Font("Ink Free", Font.BOLD, 40));
            FontMetrics metrics = getFontMetrics(g.getFont());
            g.drawString("Score: "+applesEaten, (width - metrics.stringWidth("Score: "+applesEaten))/2, g.getFont().getSize());
        }else{
            gameOver(g);
        }
    }

    public void newApple(){
        appleX = random.nextInt((int)(width/unitSize))*unitSize;
        appleY = random.nextInt((int)(height/unitSize))*unitSize;
    }

    public void move(){
        for(int i=bodyParts; i>0; i--){
            x[i] = x[i-1];
            y[i] = y[i-1];
        }

        switch(direction){
            case 'U':
                y = y - unitSize;
                break;
            case 'D':
                y = y + unitSize;
                break;
            case 'L':
                x = x - unitSize;
                break;
            case 'R':
                x = x + unitSize;
                break;
        }
    }

    public void checkApple(){
        if((x == appleX) && (y == appleY)){
            bodyParts++;
            applesEaten++;
            newApple();
        }
    }

    public void checkCollisions(){
        //check if head collides with body
        for(int i=bodyParts; i>0; i--){
            if((x == x[i]) && (y == y[i])){
                running = false;
            }
        }

        //check if head touches left border
        if(x < 0){
            running = false;
        }

        //check if head touches right border
        if(x > width){
            running = false;
        }

        //check if head touches top border
        if(y < 0){
            running = false;
        }

        //check if head touches bottom border
        if(y > height){
            running = false;
        }

        if(!running){
            timer.stop();
        }
    }

    public void gameOver(Graphics g){
        g.setColor(Color.red);
        g.setFont(new Font("Ink Free", Font.BOLD, 40));
        FontMetrics metrics1 = getFontMetrics(g.getFont());
        g.drawString("Score: "+applesEaten, (width - metrics1.stringWidth("Score: "+applesEaten))/2, g.getFont().getSize());

        g.setColor(Color.red);
        g.setFont(new Font("Ink Free", Font.BOLD, 75));
        FontMetrics metrics2 = getFontMetrics(g.getFont());
        g.drawString("Game Over", (width - metrics2.stringWidth("Game Over"))/2, height/2);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if(running){
            move();
            checkApple();
            checkCollisions();
        }
        repaint();
    }

    public class MyKeyAdapter extends KeyAdapter{
        @Override
        public void keyPressed(KeyEvent e){
            switch(e.getKeyCode()){
                case KeyEvent.VK_LEFT:
                    if(direction != 'R'){
                        direction = 'L';
                    }
                    break;
                case KeyEvent.VK_RIGHT:
                    if(direction != 'L'){
                        direction = 'R';
                    }
                    break;
                case KeyEvent.VK_UP:
                    if(direction != 'D'){
                        direction = 'U';
                    }
                    break;
                case KeyEvent.VK_DOWN:
                    if(direction != 'U'){
                        direction = 'D';
                    }
                    break;
            }
        }
    }
}