react input data and synchronize-JS Tutorial-php.cn

react input data and synchronize

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Release： 2018-06-11 15:18:40

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This time I will bring you react input data and synchronization. What are the precautions for react input data and synchronization? The following is a practical case, let's take a look.

Requirements are as follows

The length of the input content in the input box is greater than 0, and the preview information is displayed
Leave the cursor and close the preview information
Insert a special character_ every 4 digits in the preview information, and the input content remains unchanged
The length is limited to 13 digits
Only numbers (0-9) are allowed to be entered

// Zinput.js
import React, {
 Component
} from 'react';
import './Zinput.css'
// NOTE: 获取焦点事件 原生onFocus 即可
// NOTE: 离开焦点事件 原生onBlur即可
// NOTE: 输入框数据过滤 直接在change方法里进行过滤
// NOTE: 条件处理 通过不同条件返回不同节点做条件处理
class Zinput extends Component {
 constructor(props) {
  super(props);
  this.state = {
   value: '',
   showBig: false,
  };
  this.handleChange = this.handleChange.bind(this);
  this.inputOnFocus = this.inputOnFocus.bind(this);
  this.inputOnBlur = this.inputOnBlur.bind(this);
 }
 inputOnFocus() {
  if (this.state.value.length > 0) {
   this.setState({
    showBig: true
   })
  }
 }
 inputOnBlur() {
  this.setState({
   showBig: false
  })
  if(this.props.chanegNumber){
   this.props.chanegNumber(this.state.value)
  }
 }
 handleChange(event) {
  let val = event.target.value.substr(0, 13)
   .replace(/[^\d]/g, '')
  event.target.value = val
  this.setState({
   value: val,
   showBig: true,
  });
 }
 /**
  * 根据字符串没隔len位插入一个下滑杠，返回处理后的字符串
  * @method  getStr
  * @author 朱阳星
  * @datetime 2018-04-02T09:57:58+080
  * @email  zhuyangxing@foxmail.com
  * @param  {String} str 待处理字符串
  * @param  {Number} len 每隔位数插入下滑杠
  * @return  {String} 处理后的字符串
  */
 getStr(str, len) {
  let lenth = str.length
  let len1 = len - 1
  let newStr = ''
  for (var i = 0; i < lenth; i++) {
   if (i % len === len1 && i > 0) {
    newStr += str.charAt(i) + '_'
   } else {
    newStr += str.charAt(i)
   }
  }
  if (newStr.length % (len + 1) === 0) {
   // 解决最后一位为补充项问题
   newStr = newStr.substr(0, newStr.length - 1)
  }
  return newStr
 }
 render() {
  // NOTE return 需要用圆括号包住并处理
  // NOTE 条件语句里没有节点也要用空字符串进行处理 否则sonalint会报错，页面也会报错
  const showBig = this.state.showBig ? (
   <p className="big-show">{ this.getStr(this.state.value,4) }</p>
  ) : ''
  return (
   <p className="zInput">
    <input className="input" 
        type = "text" 
        onFocus={ this.inputOnFocus }
        onBlur={ this.inputOnBlur }
        value={ this.state.value } 
        onChange={ this.handleChange }>
        </input>
    {showBig}
   </p>
  )
 }
}
export default Zinput; // Don't forget to use export default!

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<!-- Zinput.css -->
.zInput{
  position: absolute;
  top:80px;
  left:40px;
  
}
.input {
 position: absolute;
 top: 0;
 left: 0;
}
.big-show {
  position: relative;
  top: -40px;
  font-size: 36px;
  line-height: 40px;
  background-color: red;
}

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Although the function is implemented, it must be used as a subcomponent of a node, and the parent component calls There are two methods

1. Use refs to directly obtain the state value of the subcomponent

constructor(props) {
 super(props);
 this.handerClick2 = this.handerClick2.bind(this);
}
handerClick2(){
 // NOTE 父组件通过refs获取子组件的state 
 console.log("使用ref获取子组件的值",this.refs.zinput.state.value)
}
render() {
 return (
  <p className="App">
   <Zinput ref="zinput"></Zinput>
   <input type="button" value="获取电话号码的值22" onClick={ this.handerClick2 }/>
  </p> 
 );
}

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2. Every time the focus of the subcomponent leaves, call the method passed by the parent component to modify the state value of the parent component.

constructor(props) {
 super(props);
 this.state = {
  phoneNumber: '',
 };
 this.handerClick = this.handerClick.bind(this);
 this.changePhoneNumber = this.changePhoneNumber.bind(this);
}
changePhoneNumber(number){
 this.setState({
   phoneNumber: number,
 })
}
handerClick(){
 // NOTE 根据react的思想是在子组件处理完某件事的时候调用父组件的方法修改父组件的state值
 console.log("使用state获取值",this.state.phoneNumber)
}
render() {
 return (
  <p className="App">
   <Zinput ref="zinput" chanegNumber={this.changePhoneNumber}></Zinput>
   <input type="button" value="获取电话号码的值" onClick={ this.handerClick }/>
  </p>
 );
}

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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!