package{
    import flash.display.Sprite;
     
    //小球 类
    public class Ball extends Sprite{
         
        private var radius:Number ;//半径
        private var color:uint;//颜色
         
        public function Ball(r:Number=50,c:uint=0xff0000){
            this.radius = r;
            this.color = c;
            init();
        }
         
        private function init():void{
            graphics.beginFill(color);
            graphics.drawCircle(0,0,radius);
            graphics.endFill();
        }
    }
}