React Native implements verification code countdown function

This time I will bring you React Native to implement Verification codeCountdown function, what are the precautions for React Native to implement verification code countdown function , the following is a practical case, let’s take a look.

Because I used timer before and did not calculate the current time. Every time I exited the program, the timer never ran. This tool class simply solves the problem of exiting the program from the background and timing. If the bug does not work, then just upload the code~~

/**
 * Created by zhuang.haipeng on 2017.9.11
 * 广告倒计时,验证码倒计时工具类
 * 用法: //60 * 1000 为60秒 , 60 * 60 * 100 为60分钟 ...
 * let countdownDate = new Date(new Date().getTime() + 60 * 1000)
 *  CountdownUtil.settimer(countdownDate, (time) => {
 *   Console.log(time) --> {years: 0, days: 0, hours: 0, min: 0, sec: 49, millisec: 0}
 *  }
 *  切记: 在应用工具类的页面退出的时候, 调用CountdownUtil.stop() 清除定时器,以免内存爆了
 */
export default class CountdownUtil {
  /** 定时器 */
  interval = null;
  /**
   * 创建定时器
   */
  static settimer(countdownDate, callbak) {
    this.interval = setInterval(() => {
      let time = this.getDateData(countdownDate)
      callbak && callbak(time)
    }, 1000)
  }
  /**
   * 侄计时计算 --> 通过此方法计算,可以解决应用退出后台的时候,定时器不走
   * @param countdownDate
   * @return {*}
   */
  static getDateData(countdownDate) {
    let diff = (Date.parse(new Date(countdownDate)) - Date.parse(new Date)) / 1000;
    if (diff <= 0) {
     this.stop() // 倒计时为0的时候, 将计时器清除
      return 0;
    }
    const timeLeft = {
      years: 0,
      days: 0,
      hours: 0,
      min: 0,
      sec: 0,
      millisec: 0,
    };
    if (diff >= (365.25 * 86400)) {
      timeLeft.years = Math.floor(diff / (365.25 * 86400));
      diff -= timeLeft.years * 365.25 * 86400;
    }
    if (diff >= 86400) {
      timeLeft.days = Math.floor(diff / 86400);
      diff -= timeLeft.days * 86400;
    }
    if (diff >= 3600) {
      timeLeft.hours = Math.floor(diff / 3600);
      diff -= timeLeft.hours * 3600;
    }
    if (diff >= 60) {
      timeLeft.min = Math.floor(diff / 60);
      diff -= timeLeft.min * 60;
    }
    timeLeft.sec = diff;
    return timeLeft;
  }
  /**
   * 数字补零 --> 例: 00时01分59秒
   * @param num
   * @param length
   * @return {*}
   */
  static leadingZeros(num, length = null) {
    let length_ = length;
    let num_ = num;
    if (length_ === null) {
      length_ = 2;
    }
    num_ = String(num_);
    while (num_.length < length_) {
      num_ = &#39;0&#39; + num_;
    }
    return num_;
  }
  /** 清除定时器 */
  static stop() {
    clearInterval(this.interval);
  }
};

Use callback to pass the converted time countdown. You can print the time object returned by callbak

Here is a simple example of the verification code countdown:

Thoughts:

1. First set the state machine isSentVerify to be true by default to send the verification code
2. After clicking, reset the state machine isSentVerify to false to prevent the user from clicking again to send a network request
3. Declare the countdown time (only here It can only be declared when you click it. If you are in componentDidMount, the time will start as soon as you enter)
4. Set the countdown after the request is successful. If time.sec > 0, set the time, otherwise the text will be set. Set it to "Reacquire"
5. Then determine the text as "Reacquire", and then set the state machine isSentVerify to true, so that the user can send the verification code again after the countdown is over.
6. When the network request fails, set isSentVerify to true at the catch point so that the user can obtain the verification code again

 if (this.state.isSentVerify === true) {
      // 倒计时时间
      let countdownDate = new Date(new Date().getTime() + 60 * 1000)
      // 点击之后验证码不能发送网络请求
      this.setState({
        isSentVerify: false
      });
      Api.userRegisterCheckCode(this.state.phoneText)
        .then(
          (data) => { // 倒计时时间
            CountdownUtil.settimer(countdownDate, (time) => {
              this.setState({
                timerTitle: time.sec > 0 ? time.sec + 's' : '重新获取'
              }, () => {
                if (this.state.timerTitle == "重新获取") {
                  this.setState({
                    isSentVerify: true
                  })
                }
              })
            })
          }
        ).catch((err) => {
        this.setState({
          isSentVerify: true,
        })
      });
    }

When exiting the page, remember to destroy the timer

 componentWillUnmount() {
    CountdownUtil.stop()
  }

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website!

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