java学习日记-------------------------------------贪吃蛇

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;


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(){//加到尾巴上
    	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;
    	node.prev=tail;
    	tail=node;//新的尾巴
    	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;
    	head.prev=node;
    	head=node;//
    	size++;
    }
    
    public void draw(Graphics g){
    	if(size<=0)return ;
    	move();
    	for(Node n=head;n!=null;n=n.next){
    		n.draw(g);
    	}
    	
    }
     private void move() {
		// TODO Auto-generated method stub
		addToHead();
		deleteFromTail();
		checkDead();
	}
	private void checkDead() {
		// TODO Auto-generated method stub
		if(head.row<2||head.col<0||head.row>Yard.ROWS||head.col>Yard.COLS){
			y.stop();
		}
		for(Node n=head.next;n!=null;n=n.next){//和自己身体碰撞
			if(head.row==n.row&&head.col==n.col){
				y.stop();
			}
		}
	}
	private void deleteFromTail() {
		// TODO Auto-generated method stub
		if(size==0)return;
		tail=tail.prev;
		tail.next=null;
	}
	class Node{
		int w=Yard.BLOCK_SIZE;
		int h=Yard.BLOCK_SIZE;
		int row,col;
		Dir dir=Dir.D;
		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())){
			e.reAppear();
			this.addToHead();
			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) {
		// TODO Auto-generated method stub
		int key=e.getKeyCode();
		switch(key){
		case KeyEvent.VK_LEFT:
			if(head.dir!=Dir.R)
			head.dir=Dir.L;
			break;
		case KeyEvent.VK_RIGHT:
			if(head.dir!=Dir.L)
			head.dir=Dir.R;
			break;
		case KeyEvent.VK_UP:
			if(head.dir!=Dir.D)
			head.dir=Dir.U;
			break;
		case KeyEvent.VK_DOWN:
			if(head.dir!=Dir.U)
			head.dir=Dir.D;
			break;
		}
	}
}

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.util.Random;


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-3)+3,r.nextInt(Yard.COLS));
	}
	
	public void reAppear(){
		this.row=r.nextInt(Yard.ROWS-3)+3;
		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 getRow() {
		return row;
	}
	public void setRow(int row) {
		this.row = row;
	}
	public int getCol() {
		return col;
	}
	public void setCol(int col) {
		this.col = col;
	}
}

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