基本路由的使用

在这里插入图片描述

本篇的vue项目，代码涉及的主要文件有：

模板文件index.html
入口文件index.js
入口组件App.js
路由组件Home：pages/Home/index.jsx
路由组件About：pages/About/index.jsx

模板文件index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <link rel="stylesheet" href="%PUBLIC_URL%/css/bootstrap.css">
    <title>React App</title>
  </head>
  <body>
    <noscript>You need to enable JavaScript to run this app.</noscript>
    <div id="root"></div>
  </body>
</html>

入口文件index.js

import React from 'react';
import ReactDOM from 'react-dom';
import {BrowserRouter} from "react-router-dom";
import App from './App';

ReactDOM.render(
  <BrowserRouter>
    <App />
  </BrowserRouter>,
  document.getElementById("root")
);

入口组件App.js

import React, { Component } from 'react'
import {NavLink,Route} from "react-router-dom";
import About from "./pages/About";
import Home from "./pages/Home";

export default class App extends Component {
  render() {
    return (
      <div>
        <div className="row">
          <div className="col-xs-offset-2 col-xs-8">
            <div className="page-header"><h2>Vue Router Demo</h2></div>
          </div>
        </div>
        <div className="row">
          <div className="col-xs-2 col-xs-offset-2">
            <div className="list-group">
              <NavLink className="list-group-item" activeClassName='active' to="/about">About</NavLink>
              <NavLink className="list-group-item" activeClassName='active' to="/home">Home</NavLink>
            </div>
          </div>
          <div className="col-xs-6">
            <div className="panel">
              <div className="panel-body">
                <Route path="/about" component={About}></Route>
                <Route path="/home" component={Home}></Route>
              </div>
            </div>
          </div>
        </div>
      </div>
    )
  }
}

pages/Home/index.jsx（Home组件）

import React, { Component } from 'react'

export default class Home extends Component {
  render() {
    return (
        <h2>我是Home的内容</h2>
    )
  }
}

pages/About/index.jsx（About组件）

import React, { Component } from 'react'

export default class About extends Component {
  render() {
    return (
        <h2>我是About的内容</h2>
    )
  }
}

Switch组件的使用

将基于以上路由基础实例，来学习Switch组件。

问题描述

新建路由组件：Business组件，pages/Business/index.jsx。

import React, { Component } from 'react'

export default class Business extends Component {
  render() {
    return (
      <div>我是Business的内容</div>
    )
  }
}

修改App.js。注册路由时，
一个路由，path="/home"时，component设置为Home组件；
另一个路由，path="/home"时，component设置为Business组件。


import React, { Component } from 'react'
import {NavLink,Route} from "react-router-dom";
import About from "./pages/About";
import Home from "./pages/Home";
import Business from "./pages/Business";

export default class App extends Component {
  render() {
    return (
      <div>
        <div className="row">
          <div className="col-xs-offset-2 col-xs-8">
            <div className="page-header"><h2>Vue Router Demo</h2></div>
          </div>
        </div>
        <div className="row">
          <div className="col-xs-2 col-xs-offset-2">
            <div className="list-group">
              <NavLink className="list-group-item" activeClassName='active' to="/about">About</NavLink>
              <NavLink className="list-group-item" activeClassName='active' to="/home">Home</NavLink>
            </div>
          </div>
          <div className="col-xs-6">
            <div className="panel">
              <div className="panel-body">
                <Route path="/about" component={About}></Route>
                <Route path="/home" component={Home}></Route>
                <Route path="/home" component={Business}></Route>
              </div>
            </div>
          </div>
        </div>
      </div>
    )
  }
}

启动应用，查看当导航切换到home时，会展示什么内容。
要么，只展示Home组件；
要么，只展示Business组件；
要么，既展示Home组件，又展示Business组件；（?）
要么，哪个组件都不展示。

也就是说，当出现以下情况时，React路由会同时展示Home组件、Business组件的内容。

<Route path="/home" component={Home}></Route>
<Route path="/home" component={Business}></Route>

使用Switch组件

针对以上问题，我们现在使用Switch组件将所有的Route组件包裹起来，修改后的App.js如下：

import React, { Component } from 'react'
import {NavLink,Switch,Route} from "react-router-dom";
import About from "./pages/About";
import Home from "./pages/Home";
import Business from "./pages/Business";

export default class App extends Component {
  render() {
    return (
      <div>
        <div className="row">
          <div className="col-xs-offset-2 col-xs-8">
            <div className="page-header"><h2>Vue Router Demo</h2></div>
          </div>
        </div>
        <div className="row">
          <div className="col-xs-2 col-xs-offset-2">
            <div className="list-group">
              <NavLink className="list-group-item" activeClassName='active' to="/about">About</NavLink>
              <NavLink className="list-group-item" activeClassName='active' to="/home">Home</NavLink>
            </div>
          </div>
          <div className="col-xs-6">
            <div className="panel">
              <div className="panel-body">
                <Switch>
                  <Route path="/about" component={About}></Route>
                  <Route path="/home" component={Home}></Route>
                  <Route path="/home" component={Business}></Route>
                </Switch>
              </div>
            </div>
          </div>
        </div>
      </div>
    )
  }
}