import java.awt.*;

import javax.swing.*;

import java.awt.event.*;

import java.util.*;

public class SnakeGame extends JFrame implements KeyListener{

private int stat=1,direction=0,bodylen=6,headx=7,heady=8,

tailx=1,taily=8,tail,foodx,foody,food;//初始化定義變數

public final int EAST=1,WEST=2,SOUTH=3,NORTH=4;//方向常量

int [][] fillblock=new int [20][20];//定義蛇身所佔位置

public SnakeGame() {//建構函式

super("貪吃蛇");

setSize(510,510);

setVisible(true);//設定視窗屬性

addKeyListener(this);//新增監聽

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

for(int i=1;i<=7;i++) fillblock[i][8]=EAST;//初始化蛇身屬性

direction=EAST;//方向初始化的設定

FoodLocate(); //定位食物

while (stat==1){

fillblock[headx][heady]=direction;

switch(direction){

case 1:headx++;break;

case 2:headx--;break;

case 3:heady++;break;

case 4:heady--;break;

}//蛇頭的前進

if(heady>19||headx>19||tailx>19||taily>19||heady<0||headx<0||tailx<0||taily<0||fillblock[headx][heady]!=0){

stat=0;

break;

} //判斷遊戲是否結束

try{

Thread.sleep(150); }

catch(InterruptedException e){}//延遲

fillblock[headx][heady]=direction;

if(headx==foodx&&heady==foody){//吃到食物

FoodLocate();

food=2;

try{

Thread.sleep(100); }

catch(InterruptedException e){}//延遲

}

if(food!=0)food--;

else{tail=fillblock[tailx][taily];

fillblock[tailx][taily]=0;//蛇尾的消除

switch(tail){

case 1:tailx++;break;

case 2:tailx--;break;

case 3:taily++;break;

case 4:taily--;break;

}//蛇尾的前進

}

repaint();

}

if(stat==0)

JOptionPane.showMessageDialog(null,"GAME OVER","Game Over",JOptionPane.INFORMATION_MESSAGE);

}

public void keyPressed(KeyEvent e) {//按鍵響應

int keyCode=e.getKeyCode();

if(stat==1) switch(keyCode){

case KeyEvent.VK_UP:if(direction!=SOUTH) direction=NORTH;break;

case KeyEvent.VK_DOWN:if(direction!=NORTH)direction=SOUTH;break;

case KeyEvent.VK_LEFT:if(direction!=EAST)direction=WEST;break;

case KeyEvent.VK_RIGHT:if (direction!=WEST)direction=EAST;break;

}

}

public void keyReleased(KeyEvent e){}//空函式

public void keyTyped(KeyEvent e){} //空函式

public void FoodLocate(){//定位食物座標

do{

Random r=new Random();

foodx=r.nextInt(20);

foody=r.nextInt(20);

}while (fillblock[foodx][foody]!=0);

}

public void paint(Graphics g){//畫圖

super.paint(g);

g.setColor(Color.BLUE);

for(int i=0;i<20;i++)

for(int j=0;j<20;j++)

if (fillblock[i][j]!=0)

g.fillRect(25*i+5,25*j+5,24,24);

g.setColor(Color.RED);

g.fillRect(foodx*25+5,foody*25+5,24,24);

}

public static void main(String[] args) {//主程式

SnakeGame application=new SnakeGame();

}

}