badsprite.java

同样是用j2me写的

import javax.microedition.lcdui.* ;
import javax.microedition.lcdui.game.* ;
import java.util.* ;
public class BadSprite extends Sprite
{
        int bx = 0 ;
        int by = 0 ;
        public BadSprite(Image img,int w,int h,int bx,int by)
        {
                super(img,w,h);
                this.bx = bx ;
                this.by = by ;
        }
        Random r = new Random(new Date().getTime()) ;
        public void AI()
        {
                int i = r.nextInt() % 4 ;
                switch(i)
                {
                        case 0:
                                moveUp() ;
                                break;
                        case 1:
                                moveDown() ;
                                break;
                        case 2:
                                moveLeft() ;
                                moveLeft() ;
                                moveLeft() ;
                                break;
                        case 3:
                                moveRight() ;
                                moveRight() ;
                                moveRight() ;
                                break;
                }
        }
        public void moveUp()
        {
                move(0,-4) ;
                //判断上边界
                if( getY() <= 0 )
                {
                        setPosition(getX(),0) ;
                }
        }
        public void moveDown()
        {
                move(0,4) ;
                //判断下边界
                if( getY() > (by - getHeight()) )
                {
                        setPosition(getX(),(by - getHeight())) ;
                }
        }
        public void moveLeft()
        {
                move(-4,0) ;
                //判断左边界
                if( getX() <= 0 )
                {
                        setPosition(0,getY()) ;
                }
        }
        public void moveRight()
        {
                move(4,0) ;
                //判断右边界
                if( getX() > (bx - getWidth()) )
                {
                        setPosition((bx - getWidth()),getY()) ;
                }
        }
}