很奇怪的报错

# main(1)

NullReferenceException

Object reference not set to an instance of an object
-------------------------------------------------------------
1 FairyGUI.DisplayObject.set_visible (Boolean value)
2 FairyGUI.GObject.HandleVisibleChanged ()
3 FairyGUI.GObject.set_visible (Boolean value)
4 Monster.OnReceiveBattleState (Boolean battleState)
以上是bugly回过来的报错
 
我看了下源码GObject里面

virtual internal protected void HandleVisibleChanged()
{
if (displayObject != null)
displayObject.visible = internalVisible2;
}
 
这里已经判断是否为空，怎么还会报错呢？？