tankcanfiresprite.java

同样是用j2me写的

import javax.microedition.lcdui.* ;
import javax.microedition.lcdui.game.* ;
public class TankCanFireSprite extends Sprite
{
        int bx = 0 ;
        int by = 0 ;
        public TankCanFireSprite(Image img,int w,int h,int bx,int by)
        {
                super(img,w,h);
                this.bx = bx ;
                this.by = by ;
        }
        public void moveUp()
        {
                move(0,-2) ;
                //判断上边界
                if( getY() <= 0 )
                {
                        setPosition(getX(),0) ;
                }
        }
        public void moveDown()
        {
                move(0,2) ;
                //判断下边界
                if( getY() > (by - getHeight()) )
                {
                        setPosition(getX(),(by - getHeight())) ;
                }
        }
        public void moveLeft()
        {
                move(-2,0) ;
                //判断左边界
                if( getX() <= 0 )
                {
                        setPosition(0,getY()) ;
                }
        }
        public void moveRight()
        {
                move(2,0) ;
                //判断右边界
                if( getX() > (bx - getWidth()) )
                {
                        setPosition((bx - getWidth()),getY()) ;
                }
        }
}