使用一

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;
public class ETListener : UnityEngine.EventSystems.EventTrigger
{
    public delegate void VoidDelegate();
    public delegate void EventDelegate(BaseEventData baseEventData);
    public delegate void BoolDelegate(bool state);
    public delegate void FloatDelegate(float delta);
    public delegate void VectorDelegate(Vector2 delta);
    public delegate void ObjectDelegate(GameObject obj);
    public delegate void KeyCodeDelegate(KeyCode key);

    public VoidDelegate onClick;
    public EventDelegate onEventClick;
    public VoidDelegate onDown;
    public VoidDelegate onEnter;
    public VoidDelegate onExit;
    public VoidDelegate onUp;
    public VoidDelegate onSelect;
    public VoidDelegate onUpdateSelect;


    static public ETListener Get(Transform transform)
    {
        ETListener listener = transform.GetComponent<ETListener>();
        if (listener == null)
            listener = transform.gameObject.AddComponent<ETListener>();
        return listener;
    }

    public override void OnPointerClick(PointerEventData eventData)
    {
        if (onClick != null)
        {
            onClick();
        }
        if (onEventClick != null)
        {
            onEventClick(eventData);
        }
    }

    public override void OnPointerDown(PointerEventData eventData)
    {
        if (onDown != null)
            onDown();
    }

    public override void OnPointerEnter(PointerEventData eventData)
    {
        if (onEnter != null)
            onEnter();
    }

    public override void OnPointerExit(PointerEventData eventData)
    {
        if (onExit != null)
            onExit();
    }

    public override void OnPointerUp(PointerEventData eventData)
    {
        if (onUp != null)
            onUp();
    }

    public override void OnSelect(BaseEventData eventData)
    {
        if (onSelect != null)
            onSelect();
    }

    public override void OnUpdateSelected(BaseEventData eventData)
    {
        if (onUpdateSelect != null)
            onUpdateSelect();
    }
}

public Button click;  
  
void Start () {  
  
    EventTriggerListener.Get(click.transform).onClick += Click;  
    EventTriggerListener.Get(click.transform).onDown += ClickDela;  
  
}  
  
  
public void Click ()  
{  
    bar = this.GetComponent<Scrollbar>();  
    bar.value = 1;  
}  
  
public void ClickDela()  
{  
    bar = this.GetComponent<Scrollbar>();  
    bar.value = 0.5f;  
}  

使用2

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;
using UnityEngine.EventSystems;

public abstract class EventTriggerListener : MonoBehaviour
{
    public abstract EventTriggerType EventType { get; }
    void Awake()
    {
        AddTriggersListener();
    }

    private void AddTriggersListener()
    {
        AddTriggersListener(gameObject);
    }

    public abstract void CallAction(BaseEventData eventData);

    /// <summary>  
    /// 为obj添加Eventrigger监听事件  
    /// </summary>  
    /// <param name="obj">添加监听的对象</param>  
    /// <param name="eventID">添加的监听类型</param>  
    /// <param name="action">触发的函数</param>  
    private void AddTriggersListener(GameObject obj)
    {
        //首先判断对象是否已经有EventTrigger组件，若没有那么需要添加  
        EventTrigger trigger = obj.GetComponent<EventTrigger>();
        if (trigger == null)
        {
            trigger = obj.AddComponent<EventTrigger>();
        }
        //实例化delegates  
        if (trigger.triggers.Count == 0)
        {
            trigger.triggers = new List<EventTrigger.Entry>();//    
        }
        //定义所要绑定的事件类型   
        EventTrigger.Entry entry = new EventTrigger.Entry();
        //设置事件类型    
        entry.eventID = EventType;
        //定义回调函数    
        UnityAction<BaseEventData> callback = new UnityAction<BaseEventData>(CallAction);
        //设置回调函数    
        entry.callback.AddListener(callback);
        //添加事件触发记录到GameObject的事件触发组件    
        trigger.triggers.Add(entry);
    }
}

使用时继承该类