[]hitArea用法问题

目标：想通过使用 hitArea 来增加按钮的点击区域（有效区向外延伸10px）；
结果：使用如下三种写法均不能达到效果，并且关闭按钮也不能关闭（去掉三种写法，点击则可正常关闭）；
请指教！
 // 写法一
let g:Laya.Graphics = new Laya.Graphics();
g.drawRect(this.closeBtn.x-10,this.closeBtn.y-10,this.closeBtn.width+20,this.closeBtn.height+20,"#FF0000");
let hitA:Laya.HitArea = new Laya.HitArea();
hitA.hit = g;
this.closeBtn.hitArea = hitA;

// 写法二
this.closeBtn.graphics.drawRect(this.closeBtn.x-10,this.closeBtn.y-10,this.closeBtn.width+20,this.closeBtn.height+20,"#FF0000");
let hitA:Laya.HitArea = new Laya.HitArea();
hitA.hit = this.closeBtn.graphics;
this.closeBtn.hitArea = hitA; 

// 写法三
let closeRect:Laya.Rectangle = new Laya.Rectangle(this.closeBtn.x-10,this.closeBtn.y-10,this.closeBtn.width+20,this.closeBtn.height+20);
this.closeBtn.hitArea = closeRect; 

// closeBtn 为 Laya.Button 实例
this.closeBtn.on(Event.CLICK,this,this.closeWin);

private closeWin():void
{
    console.log("the window has closed...");
}