https://docs.unity3d.com/Packages/com.unity.ugui@1.0/api/UnityEngine.EventSystems.html

注意：非UGUI元素要响应事件，需要在 Camera 上添加 PhysicsRaycaster 组件。

using UnityEngine;
using UnityEngine.Events;
using UnityEngine.EventSystems;

public class TestButton : MonoBehaviour, IPointerClickHandler, IPointerDownHandler, IPointerUpHandler
{
    public void OnPointerClick(PointerEventData eventData)
    {
        
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        
    }
}