void Start()
 {
     for (int i = 0; i < transform.childCount; i++)
     {
         CoordinateSystemItem cs = transform.GetChild(i).gameObject.AddComponent <CoordinateSystemItem> ();
         cs.Init(Callback);
     }
 }
 void Callback(CoordinateSystemItem cooritem)
 {
     hitchild = cooritem.transform;
 }