react_13

React Router

//-dom代表给浏览器应用使用的

npm install react-router-dom

• 目前版本是 "react-router-dom": "^6.18.0"

• 使用

  新建文件 src/router/MyRouter.tsx

• import { Navigate, RouteObject, useRoutes } from "react-router-dom";
  import { Route } from "../model/Student";
  import A8Login from "../pages/A8Login";
  import A8Main from "../pages/A8Main";
  import A8NotFound from "../pages/A8NotFound";
  import { lazy } from "react";
  import RoutesStore from "../store/RoutesStore";
  import { observer } from "mobx-react-lite";
  export function load(name: string) {
    //lazy方法可以根据字符串获得字符串组件对应着的组件标签
    const Page = lazy(() => import(`../pages/${name}`));
    console.log(Page);
    return <Page>Page>;
  }
   function MyRouter() {
    console.log(RoutesStore.routes)
    const router = useRoutes(RoutesStore.routes);
    return router;
  }
  //注意导入 router 对象时，用 observer 做了包装，这样能够在 store 发生变化时重建 router 对象
  export default observer(MyRouter)
  

  index.tsx 修改为

• import ReactDOM from "react-dom/client";
  import "./index.css";
   
  import reportWebVitals from "./reportWebVitals";
   
  import { ConfigProvider } from "antd";
  import zhCN from "antd/es/locale/zh_CN";
   
  import MyRouter from "./router/MyRouter";
  import { BrowserRouter } from "react-router-dom";
  const root = ReactDOM.createRoot(
    document.getElementById("root") as HTMLElement
  );
   
  root.render(
    <ConfigProvider locale={zhCN}>
      <BrowserRouter>
        <MyRouter>MyRouter>
      BrowserRouter>
    ConfigProvider>
  );
   
  // If you want to start measuring performance in your app, pass a function
  // to log results (for example: reportWebVitals(console.log))
  // or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
  reportWebVitals();
  

  A8Main 的代码

• import {
    DownCircleOutlined,
    MenuFoldOutlined,
    VerticalAlignTopOutlined,
  } from "@ant-design/icons";
  import { Button, Layout, Menu } from "antd";
  import { ItemType } from "antd/es/menu/hooks/useItems";
  import { Link, Navigate, Outlet, useNavigate } from "react-router-dom";
  import Icon from "../store/Icon";
  import StudentStore from "../store/StudentStore";
  import RoutesStore from "../store/RoutesStore";
  import { observer } from "mobx-react-lite";
  import { useEffect } from "react";
   
  function A8Main() {
    const items: ItemType[] = [
      {
        label: <Link to="/student">学生管理Link>,
        key: 1,
        icon: <DownCircleOutlined />,
      },
      {
        label: <Link to="/teacher">教师管理Link>,
        key: 2,
        icon: <VerticalAlignTopOutlined />,
      },
      {
        label: "用户管理",
        key: 3,
        icon: <MenuFoldOutlined />,
        children: [
          {
            label: "功能一",
            key: 31,
            icon: <Icon name="PicLeftOutlined">Icon>,
          },
          {
            label: "功能二",
            key: 32,
            icon: <Icon name="BorderHorizontalOutlined">Icon>,
          },
        ],
      },
    ];
    const nav = useNavigate();
    //点击注销按钮，清空localStorage里面和state数据，跳转到登录页面
    function onClick() {
      RoutesStore.reset();
      nav("/login");
    }
    //useEffect()的执行时机是先生成了jsx代表，然后执行了副作用，然后再渲染，正在渲染的时候执行了跳转，所以看到
    //主页一闪而过，
    /* useEffect(() => {
      if (RoutesStore.username === "") {
        nav("/login");
      }
    }, []); */
    if (RoutesStore.username === "") {
      return <Navigate to={"/login"}>Navigate>;
    }
    return (
      <Layout>
        <Layout.Header>
          <span>欢迎您【{RoutesStore.username}】span>
          <Button onClick={onClick}>注销Button>
        Layout.Header>
        <Layout>
          <Layout.Sider>
            <Menu items={RoutesStore.menus} theme="dark" mode="inline">Menu>
          Layout.Sider>
          <Layout.Content>
            <Outlet>Outlet>
          Layout.Content>
        Layout>
      Layout>
    );
  }
  export default observer(A8Main);
  

• Navigate 的作用是重定向

• load 方法的作用是懒加载组件，更重要的是根据字符串找到真正的组件，这是动态路由所需要的

• children 来进行嵌套路由映射，嵌套路由在跳转后，并不是替换整个页面，而是用新页面替换父页面的 Outlet 部分