/**
 * 贪吃蛇程序
 */
package demo1;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.*;
import javax.swing.*;
import java.util.Random;
import java.util.Timer; 
public class G1 extends JFrame {
 
 private static final long serialVersionUID = 1L;
 MyPanel p1;
 int k=0,i=0;
 public G1(){
      p1=new MyPanel();
      this.add(p1);//把面板加入到框架中
      this.addKeyListener(p1);//按键监听注册
      p1.timer.schedule(new java.util.TimerTask()//没0.2秒程序启动一遍
      {
       public void run(){
        p1.repaint();//画图片
       //判断是否吃到食物
        if(p1.snake1.x[p1.snake1.n-1]==p1.food.getM()&&p1.snake1.y[p1.snake1.n-1]==p1.food.getK())
        {
         
         switch(p1.snake1.dir) //每次画图时，变化坐标的函数
         {
         case "left":
                p1.snake1.x[p1.snake1.n]=p1.snake1.x[p1.snake1.n-1]-1;
                p1.snake1.y[p1.snake1.n]=p1.snake1.y[p1.snake1.n-1];
                break;
         case "right":
             p1.snake1.x[p1.snake1.n]=p1.snake1.x[p1.snake1.n-1]+1;
             p1.snake1.y[p1.snake1.n]=p1.snake1.y[p1.snake1.n-1];
             break;
         case "up":
            p1.snake1.y[p1.snake1.n] =p1.snake1.y[p1.snake1.n-1]-1;
            p1.snake1.x[p1.snake1.n]=p1.snake1.x[p1.snake1.n-1];
             break;
         case "down":
             p1.snake1.y[p1.snake1.n]=p1.snake1.y[p1.snake1.n-1]+1;
             p1.snake1.x[p1.snake1.n]=p1.snake1.x[p1.snake1.n-1];
             break;   
         }
         p1.snake1.n++;
         do//判断生成的食物是否和蛇重合
         {
          p1.food.change();
          k=0;
          for(i=0;i<p1.snake1.n-1;i++) {
           if(p1.snake1.x[i]==p1.food.getM()&&p1.snake1.y[i]==p1.food.getK()) 
           {
            k=1;
            break;
           }
          }
          
         }while(k!=0);
        }
        //咬到自己
        for(int i=0;i<p1.snake1.n-2;i++) {
         if(p1.snake1.x[i]==p1.snake1 .x[p1.snake1.n-1]&&p1.snake1.y[i]==p1.snake1 .y[p1.snake1.n-1]) 
         {
         p1.timer.cancel();
         } 
        }
        //撞墙游戏结束
        if(p1.snake1.x[p1.snake1.n-1]>36|p1.snake1.x[p1.snake1.n-1]<0||p1.snake1.y[p1.snake1.n-1]<0||p1.snake1.y[p1.snake1.n-1]>24) 
        {
         p1.timer.cancel();
        }
       }
      },0,200);
      this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//关闭窗口
      this.setSize(500, 400);//设置屏幕大小
      this.setVisible(true);//显示JFrame
      this.setTitle("贪吃蛇游戏");
      this.setLocation(700, 300);
       
     }
 public static void main(String[] args) 
 {
  G1 g1=new G1();
 }  
}
class MyPanel extends JPanel implements KeyListener{
 //绘画蛇身的地方
 int i,m,k;
 Snake snake1=new Snake();
 Food food=new Food();
 Timer timer=new Timer();
 JLabel ii=new JLabel("游戏分数");
 public MyPanel() {
 
    this.add(ii);
 }
 public void paint(Graphics g) {
  super.paint(g);
  g.setColor(Color.green);//设置颜色
  g.drawRect(0, 0, 380, 255);
  switch(snake1.dir) //每次画图时，变化坐标的函数
  {
  case "left":
  for(i=0;i<snake1.n-1;i++) 
  {
   snake1.x[i]=snake1.x[i+1];
   snake1.y[i]=snake1.y[i+1];
  }
     snake1.x[snake1.n-1]=snake1.x[snake1.n-2]-1;
     break;
  case "right":
   for(i=0;i<snake1.n-1;i++) 
   {
    snake1.x[i]=snake1.x[i+1];
    snake1.y[i]=snake1.y[i+1];
   }
      snake1.x[snake1.n-1]=snake1.x[snake1.n-2]+1;
      break;
  case "up":
   for(i=0;i<snake1.n-1;i++) 
   {
    snake1.x[i]=snake1.x[i+1];
    snake1.y[i]=snake1.y[i+1];
   }
     snake1.y[snake1.n-1] =snake1.y[snake1.n-2]-1;
      break;
  case "down":
   for(i=0;i<snake1.n-1;i++) 
   {
    snake1.x[i]=snake1.x[i+1];
    snake1.y[i]=snake1.y[i+1];
   }
      snake1.y[snake1.n-1]=snake1.y[snake1.n-2]+1;
      break;   
  }
  for( i=0;i<snake1.n;i++) {
   g.fill3DRect(snake1.x[i]*10, snake1.y[i]*10, 10, 10, false);
  }
  g.setColor(Color.blue);
  g.fill3DRect(food.getM()*10, food.getK()*10, 10, 10, false);
  ii.setText("游戏分数"+(snake1.n-3)*10);
  ii.setLocation(400,50);
     //画蛇一节一节
 }
public void keyPressed(KeyEvent arg0)//当按键被按下时，修改贪吃蛇的方向
 {
  if(arg0.getKeyCode()==KeyEvent.VK_DOWN&&snake1.dir!="up") {
   snake1.dir="down";
  }else if(arg0.getKeyCode()==KeyEvent.VK_LEFT&&snake1.dir!="right") {
   snake1.dir="left";
  }else if(arg0.getKeyCode()==KeyEvent.VK_RIGHT&&snake1.dir!="left") {
   snake1.dir="right";
  }else if(arg0.getKeyCode()==KeyEvent.VK_UP&&snake1.dir!="down") {
   snake1.dir="up";
  }
  
 }
 public void keyReleased(KeyEvent arg0) {
  // TODO Auto-generated method stub
  
 }
 public void keyTyped(KeyEvent arg0) {
  // TODO Auto-generated method stub
  
 }
}
class Snake//关于蛇的内容
{
 int x[]=new int[100];
 
 int y[]=new int[100];//蛇身的坐标
 String  dir="right";//蛇走的方向
 int n;//蛇的长度
 public Snake()//初始化蛇的长度，三节蛇身
 {
  this.n=3;
  this.x[0]=15;
  this.y[0]=11;
  this.x[1]=16;
  this.y[1]=11;
  this.x[2]=17;
  this.y[2]=11;
 }
 public void changesnake(int m,int k)//当吃到食物的时候，能够增加蛇身的长度
 {
  x[n]=m;
  y[n]=k;
  n++;
 }
}
class Food//蛇的食物内容
{
 int m=20;//横坐标
 int k=7;//纵坐标
 Random random = new Random();
 public void change(){
  this.m=random.nextInt(29)+2;
  this.k=random.nextInt(19)+2;     
 }
 public int getM() {
  return m;
 }
 public int getK() {
  return k;
 }
}