十五、React：简单点餐实例：知识点，html解析写法

一、功能

• 从首页列表点进去，转到详情页
• 列表、详情从Api获取
• Api列表：http://a.itying.com/api/productlist
  
  详情：http://a.itying.com/api/productcontent?id=5ac1a22011f48140d0002955

二、知识点

• 路由需要安装，并引用后才能用
• 路由的使用
• api解析：axios ；安装并引用后才能用
• 生命周期函数

三、实战

src目录结构：

【Src】
│  App.css
│  App.js
│  ...
├─components
│    Home.js
│    Pcontent.js
│    模板.js
├─css
│      basic.css
│      index.css
│      pcontent.css
└─images
        1.jpg
        2.jpg
        3.jpg

App.js

import React from 'react';
//import './App.css';
import { BrowserRouter as Router, Route } from 'react-router-dom'; //引入路由模块
import Home from './components/Home';
import Pcontent from './components/Pcontent';

function App() {
  return (
    <Router>
      <div>
        <Route exact path="/" component={Home} />
        <Route path="/Pcontent/:_id" component={Pcontent} />
      </div>
    </Router>
  );
}
export default App;

Home.js

import React,{Component} from 'react';
import {Link} from 'react-router-dom';
import '../css/index.css';
import axios from 'axios'; //或写成：const axios = require('axios');
//import { thisExpression } from '@babel/types';

class Home extends Component{
    constructor(props){
        super(props);
        this.state={
            list:[],
            domain:'http://a.itying.com/'
        }
    }

    //获取Api接口的数据
    getDataApi=()=>{
        //拼装得到完整的Api接口链接
        var api=this.state.domain+"api/productlist";
        axios.get(api)
        .then((response)=>{
            console.log(response);
            this.setState({
                list:response.data.result
            })
        })
        .catch(function(error){
            console.log(error);
        })
    }

    //生周函数：页面渲染完成后加载
    componentDidMount(){
        //调用函数得到api接口数据
        this.getDataApi();
    }

    render(){
        return(
        <div>
            <header className="index_header">
                <div className="hlist">
                    <img alt='热销榜' src={require('../images/rexiao.png')} />
                    <p>热销榜</p>
                </div>

                <div className="hlist">
                    <img alt='点过的菜' src={require('../images/caidan.png')} />
                    <p>点过的菜</p>
                </div>
                <div className="hlist">
                    <img alt='猜你喜欢' src={require('../images/sousuo.png')} />
                    <p>猜你喜欢</p>
                </div>
            </header>

            <div className="content">
                {
                this.state.list.map((value,key)=>{
                    return(
                        <div className="item" key={key}>
                        <h3 className="item_cate">{value.title}</h3>
                        <ul className="item_list">
                        {
                        value.list.map((v,k)=>{
                            return(
                                <li key={k}>
                                <div className="inner">
                                    <Link to={`/Pcontent/${v._id}`}>
                                    <img alt={v.title} src={`${this.state.domain}${v.img_url}`} />
                                    </Link>
                                    <p className="title">{v.title}</p>
                                    <p className="price">{v.price}元</p>
                                </div>
                            </li>
                            )
                        })
                        }

                        </ul>
                    </div>
                    )
                })
                }
            </div>		

        </div>
        )
    }
}
export default Home;

react解析html

 https://reactjs.org/docs/dom-elements.html
    <div className="p_content"  dangerouslySetInnerHTML={{__html: this.state.list.content}}> </div>

【Pcontent.js】

import React, { Component } from 'react';
import axios from 'axios';
import '../css/pcontent.css';
import '../css/basic.css';
import {Link} from 'react-router-dom';

class Pcontent extends Component {
    constructor(props){
        super(props);
        this.state={
          detail_list:[],
          domain:'http://a.itying.com/'
        }
    }

    componentWillMount(){
      //获取整个props查看数据结构
      console.log(this.props)
      //根据数据结构找到传过来的_id
      console.log(this.props.match.params._id)
      //根据传过来的_id获取对应详情页面
      var id=this.props.match.params._id;
      var api='http://a.itying.com/api/productcontent?id='+ id;
      axios.get(api)
      .then((response)=>{
        console.log(response);
        this.setState({
          detail_list:response.data.result[0]
        })
      })
      .catch((error)=>{
        console.log(error)
      })
    }

    render() {
      return (
        <div className='pcontent'>
            <div className="back"><Link to='/'>返回</Link></div>

		<div className="p_content">
			<div className="p_info">
				<img alt={this.state.detail_list.title} src={`${this.state.domain}${this.state.detail_list.img_url}`}/>
				<h2>{this.state.detail_list.title}</h2>
				<p className="price">{this.state.detail_list.price}元</p>
			</div>
			<div className="p_detial">
				<h3>
					商品详情
				</h3>
                {/*html解析写法*/}
				<div className="p_content"  dangerouslySetInnerHTML={{__html: this.state.detail_list.content}}>
        </div>
			</div>
		</div>

		<footer className="pfooter">
			<div className="cart">
				<strong>数量:</strong>
				<div className="cart_num">
		          <div className="input_left">-</div>
		          <div className="input_center">
		              <input type="text"  readOnly="readonly" value="1" name="num" id="num" />
		          </div>
		          <div className="input_right">+</div>
		        </div>								

			</div>

			<button className="addcart">加入购物车</button>
		</footer>
        </div>
      );
    }
  }
  export default Pcontent;

basic.css

@charset "UTF-8";
body, div, ul, li, ol, h1, h2, h3, h4, h5, h6, input, textarea, select, p, dl, dt, dd, a, img, button, form, table, th, tr, td, tbody, article, aside, details, figcaption, figure, footer, header, hgroup, menu, nav, section {
  margin: 0;
  padding: 0; }

html {
  font-size: 62.5%;
  /* 根元素是10px;     16*62.5%=10  默认在pc端根元素会解析成12px    */ }

body {
  font: 12px/1.5 'Microsoft YaHei','宋体', Tahoma, Arial, sans-serif;
  color: #555;
  background-color: #F7F7F7; }

em, i {
  font-style: normal; }

ul, li {
  list-style-type: none; }

strong {
  font-weight: normal; }

.clearfix:after {
  content: "";
  display: block;
  visibility: hidden;
  height: 0;
  clear: both; }

/*# sourceMappingURL=basic.css.map */

index.css

@charset "UTF-8";
.index_header {
  width: 96%;
  margin: 0 auto;
  height: 4.4rem;
  background: #fff;
  margin-top: 1rem;
  display: flex;
  border-radius: .5rem; }
  .index_header .hlist {
    flex: 1;
    text-align: center;
    padding-top: .2rem;
    border-right: 1px solid #eee; }
    .index_header .hlist img {
      width: 2rem;
      height: 2rem;
      margin: 0 auto; }
    .index_header .hlist:last-child {
      border-right: none; }

/*列表*/
.item .item_cate {
  text-align: center;
  padding: .5rem; }
.item .item_list {
  display: flex;
  flex-wrap: wrap;
  padding: 0px .5rem; }
  .item .item_list li {
    width: 33.3%;
    padding: .5rem;
    box-sizing: border-box; }
    .item .item_list li .inner {
      background: #fff;
      width: 100%;
      border-radius: .5rem;
      overflow: hidden; }
      .item .item_list li .inner img {
        width: 100%; }
      .item .item_list li .inner p {
        padding: .2rem .5rem; }
      .item .item_list li .inner .title {
        font-weight: bold; }

/*侧边栏*/
.left_cate {
  /*css3运动  加过渡效果*/
  transition: all 1s;
  transform: translate(-100%, 0);
  z-index: 2;
  width: 6rem;
  height: 100%;
  position: fixed;
  background: #eee;
  top: 0px;
  left: 0px; }
  .left_cate ul {
    position: absolute;
    height: 100%;
    padding: .5rem;
    z-index: 3;
    background: #eee; }
    .left_cate ul li {
      line-height: 4.4rem; }
  .left_cate .nav_cate {
    position: absolute;
    right: -3.5rem;
    background: rgba(132, 128, 128, 0.9);
    top: 42%;
    width: 5rem;
    height: 4rem;
    text-align: center;
    border-radius: 0rem 50% 50% 0rem;
    z-index: 2; }
    .left_cate .nav_cate img {
      width: 1.8rem;
      height: 1.8rem;
      margin-left: 1rem;
      margin-top: .4rem; }
    .left_cate .nav_cate p {
      color: #fff;
      margin-left: 1rem;
      margin-top: -0.3rem; }

/*透明层*/
.bg {
  position: fixed;
  width: 100%;
  height: 100%;
  background: rgba(132, 128, 128, 0.4);
  left: 0px;
  top: 0px;
  z-index: 1;
  display: none; }

/*首页导航*/
.footer_nav {
  height: 4.4rem;
  width: 4.4rem;
  background: #000;
  position: fixed;
  color: #fff;
  bottom: .5rem;
  left: .5rem;
  text-align: center;
  border-radius: 50%; }
  .footer_nav img {
    width: 1.8rem;
    height: 1.8rem;
    margin-top: .4rem; }
  .footer_nav p {
    position: relative;
    top: -0.2rem; }

/*导航弹出层*/
.footer_nav_show {
  width: 100%;
  height: 100%;
  position: fixed;
  top: 0px;
  left: 0px;
  background: rgba(0, 0, 0, 0.6);
  z-index: 2; }
  .footer_nav_show .list li {
    height: 4.4rem;
    width: 4.4rem;
    background: #000;
    position: absolute;
    color: #fff;
    left: .5rem;
    text-align: center;
    border-radius: 50%; }
    .footer_nav_show .list li img {
      width: 1.8rem;
      height: 1.8rem;
      margin-top: .4rem; }
    .footer_nav_show .list li p {
      position: relative;
      top: -0.2rem;
      font-size: 1rem; }
    .footer_nav_show .list li:nth-child(1) {
      bottom: 15.4rem;
      left: 0px; }
    .footer_nav_show .list li:nth-child(2) {
      bottom: 12.4rem;
      left: 30%;
      margin-left: -2.2rem; }
    .footer_nav_show .list li:nth-child(3) {
      bottom: 7.4rem;
      left: 45%;
      margin-left: -2.2rem; }
    .footer_nav_show .list li:nth-child(4) {
      left: 50%;
      margin-left: -2.2rem;
      bottom: .5rem; }
    .footer_nav_show .list li:nth-child(5) {
      left: .5rem;
      bottom: .5rem; }

.footer_cart {
  height: 4.4rem;
  width: 4.4rem;
  background: red;
  position: fixed;
  color: #fff;
  bottom: .5rem;
  right: .5rem;
  text-align: center;
  border-radius: 50%; }
  .footer_cart img {
    width: 1.8rem;
    height: 1.8rem;
    margin-top: .4rem; }
  .footer_cart p {
    position: relative;
    top: -0.2rem; }

/*# sourceMappingURL=index.css.map */

pcontent.css

@charset "UTF-8";
.back {
  height: 3.8rem;
  line-height: 3.8rem;
  width: 3.8rem;
  border-radius: 50%;
  background: #000;
  position: fixed;
  top: .5rem;
  left: .5rem;
  color: #fff; }
  .back:before {
    content: "";
    display: block;
    width: .8rem;
    height: .8rem;
    border-left: .2rem solid #fff;
    border-bottom: .2rem solid #fff;
    float: left;
    position: relative;
    top: 1.3rem;
    left: .6rem;
    transform: rotate(45deg);
    margin-right: .4rem; }

.p_content .p_info {
  background: #fff; }
  .p_content .p_info img {
    width: 100%;
    height: 18rem; }
  .p_content .p_info h2 {
    padding: .2rem .5rem; }
  .p_content .p_info .price {
    padding: .2rem .5rem;
    color: red; }
.p_content .p_detial {
  background: #fff;
  margin-top: 1rem; }
  .p_content .p_detial h3 {
    padding: .5rem; }
  .p_content .p_detial .p_content {
    padding: 1rem; }
    .p_content .p_detial .p_content img {
      max-width: 100%;
      display: block;
      margin: 0 auto; }
    .p_content .p_detial .p_content * {
      line-height: 1.5;
      color: #666; }

/*搴曢儴*/
.pfooter {
  position: fixed;
  bottom: 0px;
  height: 4.4rem;
  line-height: 4.4rem;
  background: #fff;
  left: 0px;
  width: 100%;
  border-top: 1px solid #eee; }
  .pfooter .cart {
    float: left;
    display: flex; }
    .pfooter .cart strong {
      flex: 1;
      font-size: 1.6rem;
      padding: 0rem .5rem; }
    .pfooter .cart .cart_num {
      width: 10rem;
      display: flex;
      margin-top: .8rem; }
      .pfooter .cart .cart_num .input_left, .pfooter .cart .cart_num .input_right {
        flex: 1;
        width: 2.8rem;
        height: 2.8rem;
        line-height: 2.8rem;
        text-align: center;
        color: red;
        border: 1px solid #eee;
        font-size: 2.4rem; }
      .pfooter .cart .cart_num .input_center {
        flex: 1; }
        .pfooter .cart .cart_num .input_center input {
          width: 2rem;
          text-align: center;
          width: 100%;
          height: 2.8rem;
          border: none;
          border-top: 1px solid #eee;
          border-bottom: 1px solid #eee;
          float: left; }
  .pfooter .addcart {
    float: right;
    background: red;
    color: #fff;
    height: 3rem;
    border: none;
    padding: 0 .5rem;
    border-radius: .5rem;
    margin-top: .8rem;
    margin-right: .5rem; }

/*# sourceMappingURL=pcontent.css.map */

效果：



http://localhost:3000/Pcontent/5ac1a22011f48140d0002955