UGUI UI层阻挡射线

public bool checkUI() {

　　PointerEventData data = new PointerEventData(eventSystem);
　　data.pressPosition = Input.mousePosition;
　　data.position= Input.mousePosition;
　　List<RaycastResult>list = new List<RaycastResult>();
　　RaycastInCanvas.Raycast(data,list);
 　   return list.Count > 0;
}