[]sprite做的按钮点击无反应？

var w:int = 110;

var h:int = 40;

var btn:Sprite = new Sprite();

btn.size(w, h);

btn.graphics.drawRect((stageWd - w) * 0.5, (stageHt - h) * 0.5-50, w, h, "#FF7F50");

 btn.graphics.fillText("确 定", (stageWd) * 0.5 , (stageHt - h) * 0.5-43, "25px SimHei", "#FFFFFF", "center");

Laya.stage.addChild(btn);

var hitArea:HitArea = new HitArea();

var graphics:Graphics  = new Graphics();

graphics.drawRect((stageWd - w) * 0.5, (stageHt - h) * 0.5-50, w, h, "#FF7F50");

hitArea.hit = graphics;

btn.hitArea = hitArea;

第二种方法：

var w:int = 110;

var h:int = 40;

var btn:Sprite = new Sprite();

btn.size(w, h);

btn.graphics.drawRect(0,0, w, h, "#FF7F50");

 btn.graphics.fillText("确 定", (stageWd) * 0.5 , (stageHt - h) * 0.5-43, "25px SimHei", "#FFFFFF", "center");

Laya.stage.addChild(btn);

btn.pos((stageWd - w) * 0.5, (stageHt - h) * 0.5-50);