react实现路由跳转

react通过路由实现页面跳转：

​ 函数式路由(withRouter)使用原生js方法实现路由功能。

​ eg：export default withRouter(Home) Home是组件名称。

	示例：
    class Home extends Component{
 		<button onClick={this.goForward}>下一级</button>
        goForward = () => {
            this.props.history.goForward()  //函数式路由
            {/* 
                this.props.history.go(0)   //正数表示调用几次goForward，负数表示调用几次goBack()，0表示刷新当前页面；
                this.props.history.goBack()  //返回上一级
                this.props.history.push('/home') //到哪去
                this.props.history.replace()  //替换当前路径 历史记录不再会有替换之前的路径
            */}
        }
    }
	
	export default withRouter(Home) 
	

一、准备工作：

​ 1、创建myProject05-router目录

​ 2、创建清单文件， npm init -y

​ 3、安装第三方依赖包，npm install react react-dom react-scripts react-router-dom@5 --save

​ 4、创建public文件夹，在该文件夹下创建index.html

​ 5、创建src文件夹，在该文件夹下创建：

​ （1）入口文件index.js

​ （2）组件App.js和App.css文件

​ （3）创建pages文件夹，在该文件夹下创建Home文件夹，在Home文件夹下创建Cates文件夹（Cates.jsx）和Goods文件夹(Goods.jsx、Goods.css），Home.jsx，Home.css；并在该文件夹下创建About.jsx和Resovle.jsx。

​ 9、src目录：

二、编写代码：

​ 1、index.html：

    <div id="root"></div>

​ 2、index.js：

import ReactDOM from 'react-dom/client'
import { BrowserRouter } from 'react-router-dom'
import App from './App'

const root = ReactDOM.createRoot(document.getElementById('root'))

root.render(
    <BrowserRouter>
        <App/>
    </BrowserRouter>
)

​ 3、App.js：

import React, { Component } from 'react'
import {NavLink, Redirect, Route, Switch} from 'react-router-dom'
import About from './pages/About'
import Home from './pages/Home/Home'
import Resovle from './pages/Resovle'
import './App.css'

export default class App extends Component {
  render() {
    return (
      <div className='app'>
          {/* 制作导航菜单 */}
          <div className='tabs'>
              <NavLink to='/home'>首页</NavLink>
              <NavLink to='/resovle'>解决方案</NavLink>
              <NavLink to='/about'>关于我们</NavLink>
          </div>


        {/* 注册路由（其实就是路径和组件的映射关系） */}
        {/* 精准匹配 */}
          <Switch>
            <Route path='/home' component={Home}/>
            <Route path='/resovle' component={Resovle}/>
            <Route path='/about' component={About}/>
            <Redirect to='/home'/>
          </Switch>
      </div>
    )
  }
}

​ 4、App.css：

.app {
    width: 400px;
    margin: 10px auto;
}

.tabs {
    display: flex;
    flex-direction: rows;

}

.tabs a{
    flex: auto;
    padding: 10px 30px ;
    background-color: #777;
    color: white;
    margin-right: 1px;
    text-decoration: none;
}

​ 5、Home.jsx

import React, { Component } from 'react'
import { NavLink, Redirect, Route, Switch } from 'react-router-dom'
import Cates from './Cates/Cates'
import Goods from './Goods/Goods'
import './Home.css'

export default class Home extends Component {
  render() {
    return (
      <div className='home'>
        <div className='left'>
          <NavLink to='/home/cates'>分类</NavLink>
          <NavLink to='/home/goods'>商品</NavLink>
        </div>

        <div className='right'>
          <Switch>
            <Route path='/home/cates' component={Cates}/>
            <Route path='/home/goods' component={Goods}/>
            <Redirect to='/home/goods'/>
          </Switch>
        </div>
      </div>
    )
  }
}

​ 6、Home.css：

.home {
    margin-top: 10px;
    display: flex;
    flex-direction: rows;
    height: 200px;
}

.home .left {
    display: flex;
    width: 120px;
    flex-direction: column;
    background-color: skyblue;
    margin-right: 1px;
}

.home .left a {
    text-decoration: none;
    color: #333;
    padding: 10px 0;
    text-align: center;
}

.home .left .active {
    background-color: orange;
}

.home .right {
    flex: auto;
    background-color: greenyellow;
}

​ 7、Cates.jsx：

import React, { Component } from 'react'

export default class Cates extends Component {
  goForward = () => {
    this.props.history.goForward()  
  }

  render() {
    return (
      <div>
         <button onClick={this.goForward}>下一级</button>
      </div>
    )
  }
}

​ 8、Goods.jsx：

import React, { Component } from 'react'

import './Goods.css'

export default class Goods extends Component {
  push = () => {
    console.log(this.props); 
    // this.props.history.push('/about')
    // this.props.history.replace('/about')  //替换当前路径记录 少一条记录
  }
  goBack = () => {
    this.props.history.goBack()
  }

  render() {
    return (
      <div className='goods'>
          <button onClick={this.push}>跳转到about</button>
          <button onClick={this.goBack}>上一级</button>

      </div>
    )
  }
}

​ 9、Goods.css：

.goods .list{
    display: flex;
    justify-content: space-around;
    background-color: plum;
}

.goods .list a {
    text-decoration: none;
    color: #333;
    margin: 10px;
}

​ 10、About.jsx：

import React, { Component } from 'react'

export default class About extends Component {
  render() {
    return (
      <div>这是关于我们内容</div>
    )
  }
}

​ 11、Resolve.jsx：

import React, { Component } from 'react'

export default class Resovle extends Component {
  render() {
    return (
      <div>这是解决方案内容</div>
    )
  }
}

三、运行命令：

​ npm react-scripts start

​ 也可以在清单文件中设置简写命令：“start”: “react-scripts start”

 "scripts": {
    "start": "react-scripts start",
    "test": "echo \\"Error: no test specified\\" && exit 1"
  },

) {
return (

## `三、运行命令：`

​			[npm react-scripts start]()

​			也可以在清单文件中设置简写命令：["start": "react-scripts start"]()

```json
 "scripts": {
    "start": "react-scripts start",
    "test": "echo \\"Error: no test specified\\" && exit 1"
  },