using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
/// <summary>
/// 提供了协程实现的倒计时封装
/// </summary>
public class XCTime : MonoBehaviour
{
    /// <summary>
    /// 回调函数
    /// </summary>
    private Action<int, int> callback;
    /// <summary>
    /// 总的CD
    /// </summary>
    private int totalSeconds;
    /// <summary>
    /// 剩余的CD
    /// </summary>
    private int surplusSeconds;
    /// <summary>
    /// 是否需要初始化
    /// </summary>
    private Boolean isNeedInited;
    /// <summary>
    /// 开始倒计时
    /// </summary>
    /// <param name="callback">回调函数 剩余秒数,总秒数</param>
    /// <param name="totalSeconds">总的秒数</param>
    /// <param name="isNeedInited">是否需要初始化(直接调用一次回调)</param>
    public void StartCD( Action<int,int> callback , int totalSeconds , Boolean isNeedInited = true )
    {
        this.StopCD();
        this.callback = callback;
        this.totalSeconds = totalSeconds;
        this.surplusSeconds = totalSeconds;
        this.isNeedInited = isNeedInited;
        if (this.totalSeconds <= 0)
        {
            if (this.isNeedInited) {
                this.callback(0, 0);
            }
            this.Clear(false);
        }
        else
        {
            if (this.isNeedInited)
            {
                this.callback(this.surplusSeconds, this.totalSeconds);
            }
            this.StartCoroutine(this.CountDown());//开启倒计时
        }
    }

    /// <summary>
    /// 停止倒计时
    /// </summary>
    public void StopCD()
    {
        this.StopCoroutine(this.CountDown());
    }
    /// <summary>
    /// 申明倒计时协程函数
    /// </summary>
    /// <returns></returns>
    private IEnumerator CountDown() 
    {
        while (true) 
        {
            yield return new WaitForSeconds(1);//每一秒执行1次
            this.surplusSeconds--;
            this.callback(this.surplusSeconds, this.totalSeconds);
            if (this.surplusSeconds <= 0) 
            {
                this.Clear(true);
                break;
            }
        }
    }

    private void Clear( Boolean isNeedStop )
    {
        if (isNeedStop) 
        {
            this.StopCD();
        }
        if (this.callback != null)
        {
            this.callback = null;
        }
    }

    public void OnDestroy()
    {
        this.Clear(true);
    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
/// <summary>
/// 此脚本用于测试倒计时
/// </summary>
[RequireComponent(typeof(XCTime))]
public class CountDownDemo : MonoBehaviour
{
    private XCTime cdHelper;
    private Text txtCD;
    // Start is called before the first frame update
    void Start()
    {
        this.cdHelper = this.gameObject.GetComponent<XCTime>();
        this.txtCD = this.gameObject.transform.Find("TxtCD").GetComponent<Text>();

        this.cdHelper.StartCD(this.ResetCD, 100, true);//开始倒计时
    }

    private void ResetCD(int surplus, int total)
    {
        this.txtCD.text = surplus.ToString();//更新数据
    }
}