UGUI判断一个点是否在UI上的方法

    public bool IsOnUI(Vector3 pos)
    {
        GraphicRaycaster caster = gameObject.GetComponent();

        PointerEventData pData = new PointerEventData(EventSystem.current);

        pData.position = pos;
        pData.delta = Vector2.zero;
        pData.scrollDelta = Vector2.zero;

        List canvasHits = new List();
        caster.Raycast(pData, canvasHits);


        return canvasHits.Count > 0;
    }

原理也是UI的射线检测。