React Router

一、简介

        react router是一个构建基于react应用的路由管理库。允许你在程序中定义不同的路由和导航规则。以实现不同的url路径显示不同的组件。

二、相关技术

<Router>
    <div>
        <ul id = "menu">
            <li><Link to = "/home">Home</Link></li>
            <li><Link to = "/hello">Hello</Link></li>
            <li><Link to = "/about">About</Link></li>
        </ul>
        
        <div id = "page-container">
            <Route path = "/home" component = {Home} />
            <Route path = "/hello" component = {Hello} />
            <Route path = "/about" component = {About} />
        </div>
    </div>
</Router>

Link - 导航跳转组件

Router -  路由配置

1.React Router API

Link -> <Link to = '/about'>About</Link> 普通连接，不会触发浏览器刷新

NavLink ->  <NavLink to = '/about' activieClassName = "selected">About</NavLink >       

Prompt ->

 <Prompt when = {fromIsHalfFilledOut}  message = "Are you sure you want to leave"/>

Redirect -> 

 <Route  exact path = "/" 
  render = {() => (loggedIn ? (<Redirect to "/dashboard"/>):
 (<PublicHomePage/>))} />

2.url传参

react 组件可以通过 match props 获取Route 中url对应的占位符值。

// 通过match属性获取Route Path中的占位符值
const Topic = ({match}) => (
    <h1>Topic {match.params.id}</h1>
); 

export default class RouterParams extends React.PureComponent{
    render(){
        return (
            <Router>
                <div>
                    <ul id = "menu">
                        <li><Link to = '/topic/1'>Topic 1</Link></li>
                        <li><Link to = '/topic/2'>Topic 2</Link></li>
                        <li><Link to = '/topic/3'>Topic 3</Link></li>
                    </ul>
                    <div id = "page-container">
                        <Route path = "/topic/:id" component = {Topic} />
                    </div>
                </div>
            </Router>
        );
    
    }

}

默认情况下，直接修改浏览器地址是不会触发跳转的，必须通过Link或者其它React routeApi实现跳转。

3.嵌套路由

1.每个React组件都是路由容器。

2.React Router的声明式语法可以方便的定义嵌套路由。

举个多级目录嵌套路由例子

// 一级目录
export const Category = () => {
    return () => {
        <Router>
            <div>
                <ul id = "menu">
                    <li><Link to = "/category/1">Category 1</Link></li>
                    <li><Link to = "/category/2">Category 2</Link></li>
                    <li><Link to = "/category/3">Category 3</Link></li>
                </ul>
                <div id = "nav-container">
                    <Route path = "/category/:id" component = {SubCategory}>
                </div>
            </div>
        </Router>
    }
}


// 二级目录
export const SecondCategory = ({match}) => {
    return () => {
        <Router>
         <div>
           <ul id = "menu">
             <li><Link to = "/category/${match.params.id}/sub/1">Category 1</Link></li>
             <li><Link to = "/category/${match.params.id}/sub/2">Category 2</Link></li>
             <li><Link to = "/category/${match.params.id}/sub/3">Category 3</Link></li>
           </ul>
           <div id = "page-container">
             <Route path = "/category/:id/sub/:subId" component = {Page}>
           </div>
         </div>            
        </Router>
    }
}


// 页面内容
export const Page = ({match}) =>{
    const data = getPageData(match.params.id, match.params.subid);
    return parseData(data);
}

 4.React router全局配置

 feature1/route.js

import Feature1Component from './FeatureComponent';

const routes = [
    {
        path: "/feature1",
        component: Feature1Component,
        exact: true
    }
];

export default routes;

route-config.js

import feature1Routes from "./feature1/route"
import feature1Routes from "./feature2/route"
const routes = [
    ...feature1Routes,
    ...feature2Routes,
]

App.js

import {BrowserRouter as Router, Route, Switch} from 'react-router-dom'
const App = () => {
    return (
        <Router>
            <Switch> // 路由选择
                {routes.map({route,index}=>{
                    <Route key = {index}
                           path = {route.path}
                           exact = {route.exact} // 精确匹配
                           render = {props => <route.component {...props}/>
                    />
                 })
                }
            </Switch>
        </Router>
    );
}