unity 如何判断鼠标是否在哪个UI上(两种方法)

 /// <summary>
        /// 获取鼠标停留处UI
        /// </summary>
        /// <param name="canvas"></param>
        /// <returns></returns>
        public GameObject GetOverUI(GameObject canvas)
        {
            PointerEventData pointerEventData = new PointerEventData(EventSystem.current);
            pointerEventData.position = Input.mousePosition;
            GraphicRaycaster gr = canvas.GetComponent<GraphicRaycaster>();
            List<RaycastResult> results = new List<RaycastResult>();
            gr.Raycast(pointerEventData, results);
            if (results.Count != 0)
            {
                return results[0].gameObject;
            }
            return null;
        }

bool isUI = RectTransformUtility.RectangleContainsScreenPoint(rect, Input.mousePosition)

void Update()
    {      
        //判断是否点击UI
        if (Input.GetMouseButtonDown(0) || (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began))
        {
            //移动端
            if (Application.platform == RuntimePlatform.Android ||
                        Application.platform == RuntimePlatform.IPhonePlayer)
            {
                int fingerId = Input.GetTouch(0).fingerId;
                if (EventSystem.current.IsPointerOverGameObject(fingerId))
                {
                    Debug.Log("点击到UI");                    
                }
            }
            //其它平台
            else
            {
                if (EventSystem.current.IsPointerOverGameObject())
                {
                    Debug.Log("点击到UI");                    
                }
            }
        }

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems; 
public class NewBehaviourScript : MonoBehaviour
{
    // Update is called once per frame
    void Update()
    {
        //移动端
        if (Application.platform == RuntimePlatform.Android ||
                    Application.platform == RuntimePlatform.IPhonePlayer)
        {
            if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began)
            {
                if (IsPointerOverGameObject(Input.GetTouch(0).position))
                {
                    Debug.Log("点击到UI");
                }
            }            
        }
        //其它平台
        else
        {
            if(Input.GetMouseButtonDown(0))
            {
                if (IsPointerOverGameObject(Input.mousePosition))
                {
                    Debug.Log("点击到UI");
                }
            }            
        }
    }
 
    /// <summary>
    /// 检测是否点击UI
    /// </summary>
    /// <param name="mousePosition"></param>
    /// <returns></returns>
    private bool IsPointerOverGameObject(Vector2 mousePosition)
    {       
        //创建一个点击事件
        PointerEventData eventData = new PointerEventData(EventSystem.current);
        eventData.position = mousePosition;
        List<RaycastResult> raycastResults = new List<RaycastResult>();
        //向点击位置发射一条射线，检测是否点击UI
        EventSystem.current.RaycastAll(eventData, raycastResults);
        if (raycastResults.Count > 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
}