贪吃蛇---练手项目1

以下是我看尚学堂并跟着视屏敲出来的代码

设置背景：

import java.awt.Color;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

/**
 *
 这个类代表贪吃蛇的活动场所
 
  
 
 
  
 
  
 */
public class Yard extends Frame {

	PaintThread paintThread = new PaintThread();//线程控制
	private boolean gameOver = false; //游戏是否结束
	
	/**
	 * 行数
	 */
	public static final int ROWS = 30;
	public static final int COLS = 30;
	public static final int BLOCK_SIZE = 15;
	
	private Font fontGameOver = new Font("宋体", Font.BOLD, 50);
	
	private int score = 0;
	
	Snake s = new Snake(this);//将该对象给蛇以得到控制权
	Egg e = new Egg();// 食物
	
	Image offScreenImage = null;
	
	public void launch() {
		this.setLocation(200, 200);
		this.setSize(COLS * BLOCK_SIZE, ROWS * BLOCK_SIZE);
		this.addWindowListener(new WindowAdapter() {

			@Override
			public void windowClosing(WindowEvent e) {
				System.exit(0);//关闭按钮
			}
			
		});
		this.setVisible(true);
		this.addKeyListener(new KeyMonitor());
		
		new Thread(paintThread).start();
	}
 
  
private class KeyMonitor extends KeyAdapter {//键盘事件响应


		@Override
		public void keyPressed(KeyEvent e) {
			int key = e.getKeyCode();
			if(key == KeyEvent.VK_F2) {
				paintThread.reStart();
			}
			s.keyPressed(e);
		}
		
	}
	
	/**
	 * 拿到所得的分数
	 * @return 分数
	 */
	
	public int getScore() {
		return score;
	}
	
	/**
	 * 设置所得的分数
	 * @param score 分数
	 */
	
	public void setScore(int score) {
		this.score = score;
	}


}
 
  
画图：
 
  
 
  
@Override
	public void paint(Graphics g) {
		Color c = g.getColor();//画笔
		g.setColor(Color.GRAY);
		g.fillRect(0, 0, COLS * BLOCK_SIZE, ROWS * BLOCK_SIZE);
		g.setColor(Color.DARK_GRAY);
		//画出横线
		for(int i=1; i
更新画面（双缓冲运用）： 
  
 
  
 
  
@Override
	public void update(Graphics g) {
		if(offScreenImage == null) {
			offScreenImage = this.createImage(COLS * BLOCK_SIZE, ROWS * BLOCK_SIZE);//生成新画面
		}
		Graphics gOff = offScreenImage.getGraphics();
		paint(gOff);//  更新画面
		g.drawImage(offScreenImage, 0, 0,  null);
	}
若是在线程中直接调用repaint（），则画面会产生闪烁，这是因为update函数没被重写，其中有个清屏的函数，就会造成一段时间没有图像，在一定频率下回产生闪烁！ 
  
 
  
以下是线程：
 
  
 
  
private class PaintThread implements Runnable {
		private boolean running = true;
		private boolean pause = false;
		public void run() {
			while(running) {
				if(pause) continue; //暂停
				else repaint();
				
				try {
					Thread.sleep(100);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		}
		
		public void pause() {
			this.pause = true;
		}
		
		public void reStart() {
			this.pause = false;
			s = new Snake(Yard.this);
			gameOver = false;
		}
		
		public void gameOver() {
			running = false;
		}
		
	}
下面是蛇的部分： 
  
 
  
 
  
public class Snake {
	private Node head = null;
	private Node tail = null;
	private int size = 0;
	
	private Node n = new Node(20, 30, Dir.L);
	private Yard y;
	
	public Snake(Yard y) {
		head = n;
		tail = n;
		size = 1;
		this.y = y;
	}
	
	public void addToTail() {
		Node node = null;
		switch(tail.dir) {
		case L :
			node = new Node(tail.row, tail.col + 1, tail.dir);
			break;
		case U :
			node = new Node(tail.row + 1, tail.col, tail.dir);
			break;
		case R :
			node = new Node(tail.row, tail.col - 1, tail.dir);
			break;
		case D :
			node = new Node(tail.row - 1, tail.col, tail.dir);
			break;
		}
		tail.next = node;//尾节点后添加节点
		node.prev = tail;
		tail = node;
		size ++;
	}
	
	public void addToHead() {
		Node node = null;
		switch(head.dir) {
		case L :
			node = new Node(head.row, head.col - 1, head.dir);
			break;
		case U :
			node = new Node(head.row - 1, head.col, head.dir);
			break;
		case R :
			node = new Node(head.row, head.col + 1, head.dir);
			break;
		case D :
			node = new Node(head.row + 1, head.col, head.dir);
			break;
		}
		node.next = head;//头节点前添加节点，往蛇的方向添加
		head.prev = node;
		head = node;
		size ++;
	}
	
	public void draw(Graphics g) {
		if(size <= 0) return;
		move();//放前面 可以使响应跟快
		for(Node n = head; n != null; n = n.next) {
			n.draw(g);
		}
	}
	
	private void move() {//移动原理： 往蛇头添加节点删除尾节点
		addToHead();
		deleteFromTail();
		checkDead();
	}

	private void checkDead() {
		if(head.row < 2 || head.col < 0 || head.row > Yard.ROWS || head.col > Yard.COLS)  {
			y.stop();
		}//超过屏幕
		
		for(Node n = head.next; n != null; n = n.next) {//咬到自己
			if(head.row == n.row && head.col == n.col) {
				y.stop();
			}
		}
	}

	private void deleteFromTail() {
		if(size == 0) return;
		tail = tail.prev;
		tail.next = null;
		
	}

	private class Node {
		int w = Yard.BLOCK_SIZE;
		int h = Yard.BLOCK_SIZE;
		int row , col;
		Dir dir = Dir.L;
		Node next = null;
		Node prev = null;
		
		Node(int row, int col, Dir dir) {
			this.row = row;
			this.col = col;
			this.dir = dir;
		}
		
		void draw(Graphics g) {
			Color c = g.getColor();
			g.setColor(Color.BLACK);
			g.fillRect(Yard.BLOCK_SIZE * col, Yard.BLOCK_SIZE * row, w, h);
			g.setColor(c);
		}
	}
	
	public void eat(Egg e) {
		if(this.getRect().intersects(e.getRect())) {//若长方形相交
			e.reAppear();//重新显示食物
			this.addToHead();//增加长度
			y.setScore(y.getScore() + 5);
		}
	}
	
	private Rectangle getRect() {
		return new Rectangle(Yard.BLOCK_SIZE * head.col, Yard.BLOCK_SIZE * head.row, head.w, head.h);
	}
	
	public void keyPressed(KeyEvent e) {//键盘控制蛇的方向
		int key = e.getKeyCode();
		switch(key) {
		case KeyEvent.VK_LEFT :
			if(head.dir != Dir.R)
				head.dir = Dir.L;
			break;
		case KeyEvent.VK_UP :
			if(head.dir != Dir.D)
				head.dir = Dir.U;
			break;
		case KeyEvent.VK_RIGHT :
			if(head.dir != Dir.L)
				head.dir = Dir.R;
			break;
		case KeyEvent.VK_DOWN :
			if(head.dir != Dir.U)
				head.dir = Dir.D;
			break;
		}
	}
}
食物的代码： 
  
 
  
 
  
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.util.Random;

/**
 * 代表蛋
 *
 */
public class Egg {
	int row, col;
	int w = Yard.BLOCK_SIZE;
	int h = Yard.BLOCK_SIZE;
	private static Random r = new Random();
	private Color color = Color.GREEN;

	public Egg(int row, int col) {
		this.row = row;
		this.col = col;
	}
	
	public Egg() {
		this(r.nextInt(Yard.ROWS-2) + 2, r.nextInt(Yard.COLS));
	}
	
	public void reAppear() {
		this.row = r.nextInt(Yard.ROWS-2) + 2;
		this.col = r.nextInt(Yard.COLS);
	}
	
	public Rectangle getRect() {
		return new Rectangle(Yard.BLOCK_SIZE * col, Yard.BLOCK_SIZE * row, w, h);
	}
	
	public void draw(Graphics g) {
		Color c = g.getColor();
		g.setColor(color);
		g.fillOval(Yard.BLOCK_SIZE * col, Yard.BLOCK_SIZE * row, w, h);
		g.setColor(c);
		if(color == Color.GREEN) color = Color.RED;
		else color = Color.GREEN;
	}

	public int getCol() {
		return col;
	}

	public void setCol(int col) {
		this.col = col;
	}

	public int getRow() {
		return row;
	}

	public void setRow(int row) {
		this.row = row;
	}
	
}
 
  
/**
 * 代表蛇的运行方向
 *
 */
public enum Dir {
	L, U, R, D
}


 
  
总结：贪吃蛇运用了多线程，双缓冲技术，适合练手