摘要：最近在用的后臺(tái)模板，從上下載后發(fā)現(xiàn)左側(cè)導(dǎo)航欄最多支持到二級(jí)菜單也發(fā)現(xiàn)很多童鞋在問(wèn)如何實(shí)現(xiàn)三級(jí)菜單。在實(shí)際的應(yīng)用場(chǎng)景中還是會(huì)出現(xiàn)三級(jí)菜單的需求的，木有其他好辦法，只能自己手動(dòng)改代碼了。

最近在用 iview-admin的Vue后臺(tái)模板，從git上下載后發(fā)現(xiàn)左側(cè)導(dǎo)航欄最多支持到二級(jí)菜單,也發(fā)現(xiàn)很多童鞋在問(wèn)如何實(shí)現(xiàn)三級(jí)菜單。在實(shí)際的應(yīng)用場(chǎng)景中還是會(huì)出現(xiàn)三級(jí)菜單的需求的，木有其他好辦法，只能自己手動(dòng)改代碼了。

1. 第一步：首先改寫(xiě)VUE中的模板，修改sidebarMenu.vue文件，文件具體目錄建下圖：

將Menu導(dǎo)航菜單組件的的二級(jí)嵌套結(jié)構(gòu)改為三級(jí)嵌套，無(wú)非就是判斷二級(jí)路由頁(yè)面下是否有children屬性及是否含有子元素，有的話直接v-for循環(huán)生成子元素標(biāo)簽，新結(jié)構(gòu)如下：

組件中methods下添加一個(gè)方法isThirdLeveMenu,判斷是否含有children屬性:

methods: {
    changeMenu(active) {
      this.$emit("on-change", active);
    },
    itemTitle(item) {
      if (typeof item.title === "object") {
        return this.$t(item.title.i18n);
      } else {
        return item.title;
      }
    },
    isThirdLeveMenu(child){
       if(child.children){
           if(child.children.length>0)return true;
           else  return false;
       }
       else {
         return false;
       }
    }
  },

第二步：修改創(chuàng)建當(dāng)前path路徑的邏輯方法：setCurrentPath ,在libs文件夾下util.js文件中：

util.setCurrentPath = function (vm, name) {
    let title = "";
    let isOtherRouter = false;
    vm.$store.state.app.routers.forEach(item => {
        if (item.children.length === 1) {
            if (item.children[0].name === name) {
                title = util.handleTitle(vm, item);
                if (item.name === "otherRouter") {
                    isOtherRouter = true;
                }
            }
        } else {
            item.children.forEach(child => {
                if (child.name === name) {
                    title = util.handleTitle(vm, child);
                    if (item.name === "otherRouter") {
                        isOtherRouter = true;
                    }
                }
            });
        }
    });
    let currentPathArr = [];
    //去首頁(yè)
    if (name === "home_index") {
        currentPathArr = [
            {
                title: util.handleTitle(vm, util.getRouterObjByName(vm.$store.state.app.routers, "home_index")),
                path: "",
                name: "home_index"
            }
        ];
    } 
    //去導(dǎo)航菜單一級(jí)頁(yè)面或者OtherRouter路由中的頁(yè)面
    else if ((name.indexOf("_index") >= 0 || isOtherRouter) && name !== "home_index") {
        currentPathArr = [
            {
                title: util.handleTitle(vm, util.getRouterObjByName(vm.$store.state.app.routers, "home_index")),
                path: "/home",
                name: "home_index"
            },
            {
                title: title,
                path: "",
                name: name
            }
        ];
    } 
    //去導(dǎo)航菜單二級(jí)頁(yè)面或三級(jí)頁(yè)面
    else {
        let currentPathObj = vm.$store.state.app.routers.filter(item => {

            var hasMenu;
            if (item.children.length <= 1) {
                hasMenu = item.children[0].name === name;
                return hasMenu;
            } else {
                let i = 0;
                let childArr = item.children;
                let len = childArr.length;
                while (i < len) {
                    //如果是三級(jí)頁(yè)面按鈕，則在二級(jí)按鈕數(shù)組中找不到這個(gè)按鈕名稱
                    //需要二級(jí)頁(yè)面下可能出現(xiàn)三級(jí)子菜單的情況邏輯加入
                    if (childArr[i].name === name) {
                        hasMenu = true;
                        return hasMenu;
                    }
                    i++;
                }
                //如果一級(jí)，二級(jí)菜單下都沒(méi)有此按鈕名稱，則遍歷三級(jí)菜單
                if(!hasMenu){
                    for(let m=0;m {
                return  child.name === name;
            })[0];

           // let thirdLevelObj =
           console.log(childObj)
           //二級(jí)頁(yè)面
            if (childObj) {
                currentPathArr = [
                    {
                        title: "首頁(yè)",
                        path: "/home",
                        name: "home_index"
                    },
                    {
                        title: currentPathObj.title,
                        path: "",
                        name: currentPathObj.name
                    },
                    {
                        title: childObj.title,
                        path: currentPathObj.path + "/" + childObj.path,
                        name: name
                    }
                ];
            }
            //childobj為undefined，再?gòu)娜?jí)頁(yè)面中遍歷
            else {
                let thirdObj;
                let childObj = currentPathObj.children.filter((child) => {
                    let hasChildren;
                    hasChildren = child.name === name;
                    if (hasChildren) return hasChildren

                    if (child.children) {
                        let sonArr = child.children;
                        for (let n = 0; n < sonArr.length; n++) {
                            if (sonArr[n].name === name) {
                                thirdObj = sonArr[n];
                                hasChildren = true;
                                return hasChildren;
                            }
                        }
                    }
                    return hasChildren
                })[0];

                if(thirdObj && childObj){
                    currentPathArr = [
                        {
                            title: "首頁(yè)",
                            path: "/home",
                            name: "home_index"
                        },
                        {
                            title: currentPathObj.title,
                            path: "",
                            name: currentPathObj.name
                        },
                        {
                            title: childObj.title,
                            path: "",               //設(shè)為空是因?yàn)榇硕?jí)菜單沒(méi)有實(shí)際頁(yè)面且用于面包屑組件顯示，path為空的將不可單擊
                            name: childObj.name
                        },
                        {
                            title: thirdObj.title,
                            path: currentPathObj.path + "/" + childObj.path + "/" + thirdObj.path,
                            name: thirdObj.name
                        }
                    ];
                }
                
            }
            
        }
    }
    
    vm.$store.commit("setCurrentPath", currentPathArr);
    return currentPathArr;
};

第三步：建立三級(jí)頁(yè)面test-child.vue,testcaca.vue和三級(jí)路由的容器組件artical-publish-center.vue
artical-publish-center.vue結(jié)構(gòu)如下圖： 要有標(biāo)簽

其他兩個(gè)三級(jí)頁(yè)面vue隨便寫(xiě)了：

第四步：到這里，容器可以實(shí)現(xiàn)期待已久三級(jí)菜單了，^_^. 在router里添加三級(jí)頁(yè)面路由，router文件夾下router.js中：
加到appRouter中吧,可以放到title: "組件"的children數(shù)組中：

{
                path: "artical-publish",
                title: "用戶配置",
                name: "artical-publish",
                icon: "compose",
                component: () => import("@/views/test/artical-publish-center.vue"), //引用三級(jí)頁(yè)面的中間容器層
                children:[
                    {
                        path: "testcaca",
                        icon: "ios-pause",
                        name: "testcaca",
                        title: "test4",
                        component: () => import("@/views/test/testcaca.vue")
                    },
                    {
                        path: "test-child",
                        icon: "ios-pause",
                        name: "test-child",
                        title: "test-child",
                        component: () => import("@/views/test/test-child.vue")
                    }
                ]
            }  

最后保存，運(yùn)行你的項(xiàng)目，看下三級(jí)菜單出來(lái)了吧：