[]list中的item类中的button注册事件不响应 是怎么回事呢 ？可以帮帮我解答下吗

class Item extends Laya.Box{
public static WID: number = 147;
public static HEI: number = 190;
private skin_progress_chip:Laya.ProgressBar;
private skin_img:Laya.Image;
private skin_chipNum:Laya.Text;
public skin_btn_use:Laya.Image;
private skin_lock:Laya.Image;
private skin_inUse:Laya.Image;
constructor(){
super();
this.size(Item.WID, Item.HEI);
this.initBuild();
this.skin_btn_use.on(Laya.Event.CLICK,this,this.onSkinBtnUseClick)
}
private onSkinBtnUseClick(){
console.log("使用");

}
 
//btn 有宽高