[游戏开发]【unity倒计时实现】---三种方法

倒计时实现—三种方法

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class CountdownDemo : MonoBehaviour
{
    //需求1秒修改一次Text的内容
    //倒计时为10秒时text变红
    private Text texttimer;
    public int second = 120;//second为int类型
    private float nextTime = 1f;

    private float totalTime = 0;//累计时间
    
    private void Start()
    {
        texttimer = this.GetComponent<Text>();

        //*方法3
        //重复调用（被执行的方法名称，第一次执行的时间，每次执行间隔）
         InvokeRepeating("Countdown1",1,1);
        //Invoke(被执行的方法，开始调用的时间);
    }
    private void Update()
    {
        //*方法1
        //Countdown1();
        //*方法2
        //Countdown2();
    }
    /// <summary>
    /// 方法1：Time.time
    /// </summary>
    public void Countdown1()
    {
        //C 货币  string.Format("{0:C3}", 2)  ＄2.000
        //D 十进制 string.Format("{0:D3}", 2)  002
        //E 科学计数法   1.20E+001   1.20E+001
        //G 常规  string.Format("{0:G}", 2)   2
        //N 用分号隔开的数字    string.Format("{0:N}", 250000)  250,000.00
        //X 十六进制    string.Format("{0:X000}", 12)   C
        // string.Format("{0:000.000}", 12.2)  012.200

        //开始时Time.time为0，nexttime为1       
        if (Time.time >= nextTime)
        {
            second--;
            texttimer.text = string.Format("{0:d2}:{1:d2}", second / 60, second % 60);
            //小于10秒时变红
            if (second <= 10)
            {
                texttimer.color = Color.red;
            }
            //设置下次修改时间
            nextTime = Time.time + 1;
        }
    }
    /// <summary>
    /// 方法2：Time.deltaTime
    /// </summary>
    public void Countdown2()
    {
        //累加每帧间隔
        totalTime += Time.deltaTime;
        if (totalTime >= 1)
        {
            second--;
            texttimer.text = string.Format("{0:d2}:{1:d2}", second / 60, second % 60);
            if (second <= 10)
            {
                texttimer.color = Color.red;
            }
            totalTime = 0;
        }
        
    }
    /// <summary>
    /// 方法3：Invoke()
    /// 每隔固定时间执行
    /// </summary>
    private void Countdown3()
    {
        second--;
        texttimer.text = string.Format("{0:d2}:{0,d2}", second / 60, second % 60);
        if (second <= 10)
        {
            texttimer.color = Color.red;
        }
        if (second<=0)
        {
            CancelInvoke("Countdown3");//取消调用
        }
    }

}