示例

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.Events;
using UnityEngine.EventSystems;
using UnityEngine.Serialization;
/// <summary>
/// Alpha渐变
/// </summary>
public class UITweenAlpha : MonoBehaviour
{
    public enum ComponentType
    {
        Graphic,
        Text
    }
    public ComponentType componentType;
    [SerializeField]
    private bool active = false;
    [Tooltip("延迟执行")]
    public float delayTime = 0;
    public float from = 1;
    public float to = 1;
    [Tooltip("持续时间")]
    public float duration = 3;
    
    public Graphic graphic;

    [Serializable]
    // 定义缓动完成后要触发的事件
    public class TweenCompletedEvent : UnityEvent { }
    // 防止序列化变量重命名后丢失引用
    [FormerlySerializedAs("onCompleted")]
    [SerializeField]
    private TweenCompletedEvent m_OnCompleted = new TweenCompletedEvent();

    private float t = 0;
    private float escapeTime = 0;
    
    private Text text;

    private void Awake()
    {
        if (graphic == null)
            graphic = this.GetComponent<Graphic>();
        if (componentType == ComponentType.Text)
            text = this.GetComponent<Text>();
    }

    void Update()
    {
        if (!active)
            return;

        escapeTime += Time.deltaTime;
        if (escapeTime < delayTime)
            return;

        if (duration <= 0 || t > duration)
            return;

        if (ComponentType.Graphic == componentType)
        {
            if (graphic == null)
                return;

            t += Time.deltaTime;
            float alpha = Mathf.Lerp(from, to, t / duration);
            Color c = graphic.color;
            c.a = alpha;
            graphic.color = c;
        }
        else
        {
            if (text == null)
                return;

            t += Time.deltaTime;
            float alpha = Mathf.Lerp(from, to, t / duration);
            Color c = text.color;
            c.a = alpha;
            text.color = c;
        }
        

        if (t >= duration)
        {
            active = false;
            m_OnCompleted.Invoke();
        }
    }

    public void SetAlpha(float a)
    {
        if (componentType == ComponentType.Graphic)
        {
            Color c = graphic.color;
            c.a = a;
            graphic.color = c;
        }
        else
        {
            Color c = text.color;
            c.a = a;
            text.color = c;
        }
    }

    public void Reset()
    {
        SetAlpha(from);
    }

    public void Play()
    {
        t = 0;
        escapeTime = 0;
        active = true;
    }

    public void Stop()
    {
        t = 0;
        escapeTime = 0;
        active = false;
    }

    public void Pause()
    {
        active = false;
    }

    public void Resume()
    {
        active = true;
    }
}