AS3误解

Question

我需要帮助......为什么我的对象不会在我告诉他但总是在同一个地方的地方产生？

 package Classes  {

    import flash.display.MovieClip;
    import flash.display.Sprite;
    import flash.display.Stage;
    import flash.events.Event;

    public class sy_player extends Sprite{

        public function sy_player(skin:int,startX:int ,startY:int):void {

            this.x = startX;
            this.y = startY;

        }
        }
    }

在主课程中：

public class Main extends MovieClip {


    public function Main() {
        var player:sy_player = new sy_player(0,100,300);
        addChild(player);


    }
}