ElementUI 复杂顶部和左侧导航栏实现

描述：如图

项目路径如下图所示：

代码实现：

首先在store.js中添加两个状态：

import Vue from 'vue'
import Vuex from 'vuex'
Vue.use(Vuex)
const state = {
    topNavState: 'home',
    leftNavState: 'home'
}
export default new Vuex.Store({
    state
})

App.vue内容：

<template>
  <div id="app">
    <router-view></router-view>
  </div>
</template>
<script>
  export default {
    name: 'app'
  }
</script>

main.js代码：

import Vue from 'vue'
import App from './App'
import router from './router'
import ElementUI from 'element-ui'
import store from './store.js'

import 'element-ui/lib/theme-chalk/index.css'
import '@/assets/iconfont.css'
import '@/assets/css/style.css'

Vue.config.productionTip = false
Vue.use(ElementUI)

new Vue({
    router,
    store,
    el: '#app',
    render: h => h(App)
})

router/index.js文件声明路由：

其中：行程计划、任务、通讯录属于首页大板块（topNavState=“home”）；企业信息、车辆信息、部门信息都属于enterprise这一大板块（topNavState=“enterprise”）

import Vue from 'vue'
import Router from 'vue-router'
import LeftNav from '@/components/nav/leftNav.vue'
import Home from '@/views/home.vue'
import Dashboard from '@/views/workbench/dashboard.vue'
import Mission from '@/views/workbench/mission/mission.vue'
import Plan from '@/views/workbench/plan.vue'
import Maillist from '@/views/workbench/maillist.vue'
import EnterpriseList from '@/views/enterprise/index.vue'
import EnterpriseAdd from '@/views/enterprise/add.vue'
import EnterpriseDetail from '@/views/enterprise/detail.vue'
import EnterpriseValidate from '@/views/enterprise/validate.vue'
import VehicleManage from '@/views/vehicle/index.vue'
import DeptManager from '@/views/dept/index.vue'
import NotFound from '@/components/404.vue'

// 懒加载方式，当路由被访问的时候才加载对应组件
const Login = resolve => require(['@/views/login'], resolve)

Vue.use(Router)

let router = new Router({
  routes: [
    {
      path: '/login',
      type: 'login',
      component: Login
    },
    {
      path: '*',
      component: NotFound
    },
    {
      path: '/',
      type: 'home', // 根据type区分不同模块（顶部导航）
      name: 'home', // 根据name区分不同子模块（左侧导航）
      redirect: '/dashboard',
      component: Home,
      menuShow: true,
      children: [
        {
          path: '/dashboard',
          component: LeftNav,
          name: 'dashboard', // 当前路由的name
          leaf: true, // 只有一个节点
          iconCls: 'iconfont icon-home', // 图标样式class
          menuShow: true,
          children: [
            { path: '/dashboard', component: Dashboard, name: '首页', menuShow: true }
          ]
        },
        {
          path: '/mySet',
          component: LeftNav,
          name: '我的设置',
          iconCls: 'el-icon-menu',
          menuShow: true,
          children: [
            { path: '/mySet/plan', component: Plan, name: '行程计划', menuShow: true },
            { path: '/mySet/mission', component: Mission, name: '我的任务', menuShow: true },
            { path: '/mySet/maillist', component: Maillist, name: '通讯录', menuShow: true }
          ]
        }
      ]
    },
    {
      path: '/enterpriseManager',
      type: 'enterprise',
      name: 'enterprise',
      component: Home,
      redirect: '/enterprise/list',
      menuShow: true,
      children: [
        {
          path: '/enterpriseList',
          component: LeftNav,
          name: 'enterpriseList',
          leaf: true, // 只有一个节点
          iconCls: 'iconfont icon-home', // 图标样式class
          menuShow: true,
          children: [
            { path: '/enterprise/list', component: EnterpriseList, name: '企业列表', menuShow: true },
            { path: '/enterprise/detail', component: EnterpriseDetail, name: '企业详情', menuShow: false }
          ]
        },
        {
          path: '/enterpriseAdd',
          component: LeftNav,
          name: 'enterpriseAdd',
          leaf: true, // 只有一个节点
          iconCls: 'el-icon-menu',
          menuShow: true,
          children: [
            { path: '/enterprise/add', component: EnterpriseAdd, name: '企业添加', menuShow: true }
          ]
        },
        {
          path: '/enterpriseValidate',
          component: LeftNav,
          name: 'enterpriseValidate',
          leaf: true, // 只有一个节点
          iconCls: 'el-icon-menu',
          menuShow: true,
          children: [
            { path: '/enterprise/validate', component: EnterpriseValidate, name: '企业认证', menuShow: true }
          ]
        }
      ]
    },
    {
      path: '/vehicleManager',
      type: 'enterprise',
      name: 'vehicle',
      component: Home,
      redirect: '/vehicle/list',
      menuShow: true,
      children: [
        {
          path: '/vehicleList',
          component: LeftNav,
          name: 'vehicleList',
          leaf: true, // 只有一个节点
          iconCls: 'iconfont icon-home', // 图标样式class
          menuShow: true,
          children: [
            { path: '/vehicle/list', component: VehicleManage, name: '车辆信息', menuShow: true }
          ]
        }
      ]
    },
    {
      path: '/deptManager',
      type: 'enterprise',
      name: 'dept',
      component: Home,
      redirect: '/dept/list',
      menuShow: true,
      children: [
        {
          path: '/deptList',
          component: LeftNav,
          name: 'deptList',
          leaf: true, // 只有一个节点
          iconCls: 'iconfont icon-home', // 图标样式class
          menuShow: true,
          children: [
            { path: '/dept/list', component: DeptManager, name: '部门信息', menuShow: true }
          ]
        }
      ]
    }

  ]
});

router.beforeEach((to, from, next) => {
  // console.log('to:' + to.path)
  if (to.path.startsWith('/login')) {
    window.localStorage.removeItem('access-user')
    next()
  } else if(to.path.startsWith('/register')){
    window.localStorage.removeItem('access-user')
    next()
  } else {
    let user = JSON.parse(window.localStorage.getItem('access-user'))
    if (!user) {
      next({path: '/login'})
    } else {
      next()
    }
  }
});

export default router

 特别说明：

这里的路由对象router ，设置的是最多三级，一级路由主要对应的是顶部导航和其他无子页面的路由，二级和三级路由分别对应的是左侧导航的一级和二级菜单（比如三级路由对应的就是左侧导航的二级菜单），二级路由设置leaf属性，值为true表明该路由下没有子菜单（如果该路由下的某页面不显示在左侧导航，不算子菜单）。

leftNav.vue文件中主要是左侧导航菜单加载代码：

<template>
  <el-col :span="24" class="main">
    <!--左侧导航-->
    <aside :class="{showSidebar:!collapsed}">
      <!--展开折叠开关-->
      <div class="menu-toggle" @click.prevent="collapse">
        <i class="iconfont icon-outdent" v-show="!collapsed" title="收起"></i>
        <i class="iconfont icon-indent" v-show="collapsed" title="展开"></i>
      </div>
      <!--导航菜单-->
      <el-menu :default-active="$route.path" router :collapse="collapsed" ref="leftNavigation">
        <template v-for="(issue,index) in $router.options.routes">
          <template v-if="issue.name === $store.state.leftNavState"><!-- 注意：这里就是leftNavState状态作用之处，当该值与router的根路由的name相等时加载相应菜单组 -->
            <template v-for="(item,index) in issue.children">
              <el-submenu v-if="!item.leaf" :index="index+''" v-show="item.menuShow">
                <template slot="title"><i :class="item.iconCls"></i><span slot="title">{{item.name}}</span></template>
                <el-menu-item v-for="term in item.children" :key="term.path" :index="term.path" v-if="term.menuShow"
                              :class="$route.path==term.path?'is-active':''">
                  <i :class="term.iconCls"></i><span slot="title">{{term.name}}</span>
                </el-menu-item>
              </el-submenu>
              <el-menu-item v-else-if="item.leaf&&item.children&&item.children.length" :index="item.children[0].path"
                            :class="$route.path==item.children[0].path?'is-active':''" v-show="item.menuShow">
                <i :class="item.iconCls"></i><span slot="title">{{item.children[0].name}}</span>
              </el-menu-item>
            </template>
          </template>
        </template>
      </el-menu>
    </aside>
    <!--右侧内容区-->
    <section class="content-container">
      <div class="grid-content bg-purple-light">
        <el-col :span="24" class="content-wrapper">
          <transition name="fade" mode="out-in">
            <router-view></router-view>
          </transition>
        </el-col>
      </div>
    </section>
  </el-col>
</template>
<script>
  export default {
    name: 'leftNav',
    data () {
      return {
        collapsed: false
      }
    },
    methods: {
      //折叠导航栏
      collapse: function () {
        this.collapsed = !this.collapsed;
      },
      // 左侧导航栏根据当前路径默认打开子菜单（如果当前路由是三级，则父级子菜单默认打开）
      defaultLeftNavOpened () {
        let cur_path = this.$route.path; //获取当前路由
        let routers = this.$router.options.routes; // 获取路由对象
        let subMenuIndex = 0, needOpenSubmenu = false;
        for (let i = 0; i < routers.length; i++) {
          let children = routers[i].children;
          if(children){
            for (let j = 0; j < children.length; j++) {
              if (children[j].path === cur_path) {
                break;
              }
              // 如果该菜单下有子菜单(个数>1且设置的leaf为false才有下拉子菜单)
              if(children[j].children && !children[j].leaf) {
                let grandChildren = children[j].children;
                for(let z=0; z<grandChildren.length; z++) {
                  if(grandChildren[z].path === cur_path) {
                    subMenuIndex = j;
                    needOpenSubmenu = true;
                    break;
                  }
                }
              }
            }
          }
        }
        if(this.$refs['leftNavigation'] && needOpenSubmenu) {
          this.$refs['leftNavigation'].open(subMenuIndex); // 打开子菜单
        }
      },
    },
    mounted() {
      this.defaultLeftNavOpened();
    }
  }
</script>

home.vue是后台主页组件代码

<template>
  <el-row class="container">
    <!--头部-->
    <el-col :span="24" class="topbar-wrap">
      <div class="topbar-logo topbar-btn">
        <a href="/"><img src="../assets/logo.png" style="padding-left:8px;"></a>
      </div>
      <div class="topbar-logos" v-show="!collapsed">
        <a href="/" style="color: #fff;">车车综合管理</a>
      </div>
      <div class="topbar-title">
        <el-row v-show="$store.state.topNavState==='home'"><!-- 注意：这里就是topNavState作用之处，根据当前路由所在根路由的type值判断显示不同顶部导航菜单 -->
          <el-col :span="24">
            <el-menu :default-active="defaultActiveIndex" class="el-menu-demo" mode="horizontal" @select="handleSelect" :router="true">
              <el-menu-item index="/">工作台</el-menu-item>
              <el-menu-item index="/enterpriseManager">企业管理</el-menu-item>
              <el-menu-item index="/orderManager">订单管理</el-menu-item>
              <el-menu-item index="/systemManager">系统管理</el-menu-item>
            </el-menu>
          </el-col>
        </el-row>
        <el-row v-show="$store.state.topNavState==='enterprise'">
          <el-col :span="24">
            <el-menu :default-active="defaultActiveIndex" class="el-menu-demo" mode="horizontal" @select="handleSelect" :router="true">
              <el-menu-item index="/enterpriseManager">企业信息</el-menu-item>
              <el-menu-item index="/vehicleManager">车辆信息</el-menu-item>
              <el-menu-item index="/deptManager">组织架构</el-menu-item>
            </el-menu>
          </el-col>
        </el-row>
      </div>
      <div class="topbar-account topbar-btn">
        <el-dropdown trigger="click">
          <span class="el-dropdown-link userinfo-inner">
            <i class="iconfont icon-user"></i> {{nickname}}   <i class="el-icon-caret-bottom"></i></span>
          <el-dropdown-menu slot="dropdown">
            <el-dropdown-item>
              <div @click="jumpTo('/user/profile')"><span style="color: #555;font-size: 14px;">个人信息</span></div>
            </el-dropdown-item>
            <el-dropdown-item>
              <div @click="jumpTo('/user/changepwd')"><span style="color: #555;font-size: 14px;">修改密码</span></div>
            </el-dropdown-item>
            <el-dropdown-item divided @click.native="logout">退出登录</el-dropdown-item>
          </el-dropdown-menu>
        </el-dropdown>
      </div>
    </el-col>

    <!--中间-->
    <transition name="fade" mode="out-in">
      <router-view></router-view>
    </transition>
  </el-row>
</template>
<script>
  export default {
    name: 'home',
    data () {
      return {
        defaultActiveIndex: "/",
        loading: false,
        nickname: '',
        collapsed: false
      }
    },
    created() {// 组件创建完后获取数据，
      // 此时 data 已经被 observed 了
      this.fetchNavData();
    },
    methods: {
      handleSelect(index){
        this.defaultActiveIndex = index;
      },
      //折叠导航栏
      collapse () {
        this.collapsed = !this.collapsed;
      },
      fetchNavData () { // 初始化菜单激活项
        var cur_path = this.$route.path; //获取当前路由
        var routers = this.$router.options.routes; // 获取路由对象
        var nav_type = "", nav_name = "";
        for (var i = 0; i < routers.length; i++) {
          var children = routers[i].children;
          if(children){
            for (var j = 0; j < children.length; j++) {
              var grand_children = children[j].children;
              if(grand_children){
                for (var k = 0; k < grand_children.length; k++) {
                  if (grand_children[k].path === cur_path) {
                    nav_type = routers[i].type;
                    nav_name = routers[i].name;
                    break;
                  }
                  // 如果该菜单下还有子菜单
                  if(children[j].children) {
                    let grandChildren = children[j].children;
                    for(let z=0; z<grandChildren.length; z++) {
                      if(grandChildren[z].path === cur_path) {
                        nav_type = routers[i].type;
                        nav_name = routers[i].name;
                        break;
                      }
                    }
                  }
                }
              }
            }
          }
        }
        this.$store.state.topNavState = nav_type;  // 改变topNavState状态的值
        this.$store.state.leftNavState = nav_name;  // 改变leftNavState状态的值
        if(nav_type == "home"){
          this.defaultActiveIndex = "/";
        } else {
          this.defaultActiveIndex = "/" + nav_name + "Manager";
        }
      },
      jumpTo(url){
        this.defaultActiveIndex = url;
        this.$router.push(url); //用go刷新
      },
      logout(){
        //logout
        let that = this;
        this.$confirm('确认退出吗?', '提示', {
          confirmButtonClass: 'el-button--warning'
        }).then(() => {
          //确认
          localStorage.removeItem('access-user');
          that.$router.go('/login'); //用go刷新
        }).catch(() => {});
      }
    },
    mounted() {
      let user = localStorage.getItem('access-user');
      if (user) {
        user = JSON.parse(user);
        this.nickname = user.nickname || '';
      }
    },
    watch: {
      '$route': 'fetchNavData'  //监听router值改变时，改变导航菜单激活项
    }
  }
</script>

注意fetchNavData()这个方法，主要是根据当前跳转的路由，去找到这个路由对应的type（对应顶部导航栏的分类）和name（对应左侧导航栏的分类），然后保存type和name到$store中，这样在顶部导航可以根据$store中的type显示相应的菜单，同样在左侧导航就可以取到这个name值并显示相应的左侧菜单栏了。

之前写的左侧导航栏（leftNav.vue）的代码有个不足的地方——当前打开页面是三级路由（也就是左侧导航的二级菜单）时，刷新当前页，（在左侧导航中）当前路由所属的一级菜单没有默认打开。

解决方案已修改，在leftNav.vue中添加defaultLeftNavOpened()方法，详情可以回看leftNav.vue的代码。

对于这个项目的demo，也放到了github共享，请看github地址：https://github.com/yqrong/ccproject.git

最近这段时间把项目修改了下（将顶部导航也提取出来作为命名视图），详情请看下篇：

ElementUI+命名视图实现复杂顶部和左侧导航栏

补充：

今天有位细心的网友发现了一个小问题：

左侧导航当前激活的是非第一个菜单时，切换其他顶部导航再切换回来，会有两个激活的菜单。

解决：el-menu标签缺少default-active属性设置，加上即可。

<el-menu :default-active="$route.path" router :collapse="collapsed" ref="leftNavigation">
<!-- ... -->
</el-menu>

写代码还是不够细心，自我检讨一下。