Yard

package com.Snake;

import java.awt.*;
import java.awt.event.*;

public class Yard extends Frame{
    
	public static final int NodeSize=10;
	public static final int NodeCount=30;
	public static final int AreaSize =NodeSize*NodeCount;
	public static int x=AreaSize/2;
	public static int y=AreaSize/2;
	Egg e=new Egg(10,10);
	Snake s=new Snake();
	public static void main(String[] args) {
    
		// TODO Auto-generated method stub
		new Yard();
	}
	Yard(){
    
		this.setTitle("贪吃蛇1.0（不死版）");
		this.setSize(2*AreaSize,2*AreaSize);
		this.setVisible(true);
		this.addWindowListener(new WindowAdapter() {
    
			public void windowClosing(WindowEvent e) {
    
				System.exit(0);
			}
		});
		
		this.addKeyListener(new KeyAdapter() {
    
			public void keyPressed(KeyEvent e) {
    
				s.keyPressed(e);
			}
		});
		while(true) {
    
			try {
    
				Thread.sleep(50);
			} catch (InterruptedException e1) {
    
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
			this.repaint();
		}
	}
	public void paint(Graphics g) {
    
		Color c=g.getColor();
		g.setColor(Color.white);
		g.fillRect(0,0,this.getWidth(),this.getHeight());
		g.setColor(Color.BLACK);
		for(int i=0;i<=NodeCount;i++) {
    
			g.drawLine(x,y+NodeSize*i,x+AreaSize,y+NodeSize*i);
			g.drawLine(x+NodeSize*i,y,x+NodeSize*i,y+AreaSize);
		}
		e.paint(g);
		s.paint(g);
		s.eat(e);
	}
	
	//双缓冲 double buffer 
	Image offScreenImage = null;
	@Override
	public void update(Graphics g) {
    
		if(offScreenImage == null) {
    
			offScreenImage =this.createImage(this.getWidth(),this.getHeight());
		}
		Graphics gOff = offScreenImage.getGraphics();
		paint(gOff);
		g.drawImage(offScreenImage,0,0,null);
	}
}

package com.Snake;

import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.util.*;

public class Snake {
    
	Node head,tail;
	Dir dir=Dir.L;
	Random r=new Random();
	Snake(){
    
		head=new Node(20,20);
		tail=head;
	}
	public void addToHead() {
    
		Node n=null;
		switch(dir) {
    
		case L:
			n =new Node(head.row,head.col-1);
			break;
		case U:
			n=new Node(head.row-1,head.col);
			break;
		case R:
			n=new Node(head.row,head.col+1);
			break;
		case D:
			n=new Node(head.row+1,head.col);
		}
		n.next=head;
		head.prev=n;
		head =n;
	}
	public void paint(Graphics g) {
    
		// TODO Auto-generated method stub
		Node n=head;
		while(n!=null) {
    
			n.paint(g);
			n=n.next;
			move();
		}
		
	}
	private void move() {
    
		addToHead();
		deleteTail();
		boundaryChexk();
	}
	private void boundaryChexk() {
    
		// TODO Auto-generated method stub
		if(head.row<0)head.row=Yard.NodeCount-1;
		if(head.col<0)head.col=Yard.NodeCount-1;
		if(head.row>Yard.NodeCount-1)head.row=0;
		if(head.col>Yard.NodeCount-1)head.col=0;
	}
	private void deleteTail() {
    
		if(tail==null)return;
		tail=tail.prev;
		tail.next.prev=null;
		tail.next=null;
	}
	public void keyPressed(KeyEvent e) {
    
		// TODO Auto-generated method stub
		int key=e.getKeyCode();
		switch(key) {
    
			case KeyEvent.VK_LEFT: dir=Dir.L;
			break;
			case KeyEvent.VK_UP:dir=Dir.U;
				break;
			case KeyEvent.VK_RIGHT:dir=Dir.R;
				break;
			case KeyEvent.VK_DOWN:dir=Dir.D;
				break;
				
		}
	}
	public void eat(Egg e) {
    
		// TODO Auto-generated method stub
		if(head.row==e.row&&head.col==e.col) {
    
			addToHead();
			e.reAppear();
		}
	}

}

package com.Snake;

import java.awt.Color;
import java.awt.Graphics;
import java.util.*;

public class Egg {
    
	int row,col;
	Random r=new Random();
	Egg(int row,int col){
    
		this.row=row;
		this.col=col;
	}
	public void paint(Graphics g) {
    
		// TODO Auto-generated method stub
		int x=Yard.x + col*Yard.NodeSize;
		int y=Yard.y + row*Yard.NodeSize;
		// TODO Auto-generated method stub
		Color c=g.getColor();
		g.setColor(Color.RED);
		g.fillOval(x,y,Yard.NodeSize,Yard.NodeSize);
		g.setColor(c);
	}
	public void reAppear() {
    
		// TODO Auto-generated method stub
		this.row=r.nextInt(Yard.NodeCount);
		this.col=r.nextInt(Yard.NodeCount);
	}
}

package com.Snake;

public enum Dir{
    
	L,U,R,D;
}