1.在app.json文件中，添加自定义tabbar配置："custom": true

  "tabBar": {
    "custom": true,
    "backgroundColor": "#fafafa",
    "borderStyle": "white",
    "selectedColor": "#40ae36",   
    "color": "#666",
    "list": [
      {
        "pagePath": "pages/index/index",
        "iconPath": "static/images/home.png",
        "selectedIconPath": "static/images/home@selected.png",
        "text": "首页"
      },
      {
        "pagePath": "pages/adoptProduct/adoptProduct",
        "iconPath": "static/images/adopt.png",
        "selectedIconPath": "static/images/adopt@selected.png",
        "text": "认养"
      },
      {
        "pagePath": "pages/supermarket/supermarket",
        "iconPath": "static/images/supermarket.png",
        "selectedIconPath": "static/images/supermarket@selected.png",
        "text": "农副超市"
      },     
      {
        "pagePath": "pages/ucenter/index/index",
        "iconPath": "static/images/my.png",
        "selectedIconPath": "static/images/my@selected.png",
        "text": "我的"
      }
    ]
  }

2.新建根目录文件

index.wxml

<view class="tabBar">
  <view class="cont">
    <block wx:for="{{tabBar.list}}" wx:key="index" class="cont-item">
      <view data-path="{{item.pagePath}}" data-index="{{item.pagePath}}" bindtap="switchTab" class="{{item.search?'search':'item'}} {{tabIndex === index ? 'on' : 'off'}}">
        <image src="{{tabIndex === index  ? item.selectedIconPath : item.iconPath}}"></image>
        <view class="txt {{tabIndex === index ? 'selectedColor' : ''}}">{{item.text}}</view>
      </view>
    </block>
  </view>
</view>

index.wxss

.tabBar {
  z-index: 100;
  width: 100%;
  position: fixed;
  bottom: 0;
  font-size: 28rpx;
  background-color: #fff;
  color: #636363;
}
.cont {
  z-index: 0;
  height: calc(100rpx + env(safe-area-inset-bottom) / 2);
  padding-bottom: calc(env(safe-area-inset-bottom) / 2); 
  padding-bottom: 30rpx;
  display: flex;
  justify-content: space-around;
}
.cont .item {
  font-size: 24rpx;
  position: relative;
  width: 15%;
  text-align: center;
  padding: 0;
  display: block;
  height: auto;
  line-height: 1;
  margin: 0;
  background-color: inherit;
  overflow: initial;
  justify-content: center;
  align-items: center;
  padding-top: 20rpx;
}
.cont .item image {
  width: 50rpx !important;
  height: 50rpx !important;
  margin: auto
}
.cont .selectedColor {
  color: #40ae36;
}
.txt{
  font-size: 24rpx;
}

index.js

//获取应用实例
const app = getApp();
Component({
  data: {},
  methods: {
    switchTab(e) { 
      const data = e.currentTarget.dataset
      const url = data.path
      wx.switchTab({url})
    }
  }
})

index.json

{ 
  "component": true,
  "usingComponents": {}
}

3.在utils添加tab-service.js(通过接口请求，去判断显示那个tabbar)

let tabData = {
  tabIndex: 0,//底部按钮高亮下标
  tabBar: {
      custom: true,
      color: "#5F5F5F",
      selectedColor: "#07c160",
      backgroundColor: "#F7F7F7",
      list: []
  }
}

// 更新菜单
const updateRole = (that, type) => {
 if (type === '0') {
    tabData.tabBar.list=[{
      pagePath: "/pages/index/index",
      iconPath: "/static/images/home.png",
      selectedIconPath: "/static/images/home@selected.png",
      text: "首页"
    },
    {
      pagePath: "/pages/adoptProduct/adoptProduct",
      iconPath: "/static/images/adopt.png",
      selectedIconPath: "/static/images/adopt@selected.png",
      text: "认养"
    },
    {
      pagePath: "/pages/supermarket/supermarket",
      iconPath: "/static/images/supermarket.png",
      selectedIconPath: "/static/images/supermarket@selected.png",
      text: "农副超市"
    },     
    {
      pagePath: "/pages/ucenter/index/index",
      iconPath: "/static/images/my.png",
      selectedIconPath: "/static/images/my@selected.png",
      text: "我的"
    }]
  }else if (type === '1'){
    tabData.tabBar.list= [{
      pagePath: "/pages/index/index",
      iconPath: "/static/images/home.png",
      selectedIconPath: "/static/images/home@selected.png",
      text: "首页"
    },
    {
      pagePath: "/pages/supermarket/supermarket",
      iconPath: "/static/images/supermarket.png",
      selectedIconPath: "/static/images/supermarket@selected.png",
      text: "农副超市"
    },     
    {
      pagePath: "/pages/ucenter/index/index",
      iconPath: "/static/images/my.png",
      selectedIconPath: "/static/images/my@selected.png",
      text: "我的"
    }]
  } 
  updateTab(that);
}
 
// 更新底部高亮
const updateIndex = (that, index) => {
  tabData.tabIndex = index;
  updateTab(that);
}
 
// 更新Tab状态
const updateTab = (that) => {
  if (typeof that.getTabBar === 'function' && that.getTabBar()) {
      that.getTabBar().setData(tabData);
  }
}
 
// 将可调用的方法抛出让外面调用
module.exports = {
  updateRole, updateTab, updateIndex,tabBar:tabData.tabBar.list
}

4.在tabbar对应界面添加

tabService.updateRole(this,'0') // 显示所有tabbar4个
tabService.updateRole(this,'1') // 显示tabbar中的3个
tabService.updateIndex(this, 0)  // tabbar高亮

首页中的index.js

 onShow(){ 
    this.chooseMenu()
    tabService.updateIndex(this, 0)  // tabbar高亮
  }
 chooseMenu(){
        util.request(api.chooseMenu, {
        }, 'GET').then(res => {
          if (res.errno === 0) {
            if(res.data == 1 ) {
              tabService.updateRole(this,'1')
            }else {
              tabService.updateRole(this,'0')
            }
          }
          else{
            util.showErrorToast(res.errmsg);
          }
        })
      }

我的页面中的index.js

 onShow(){ 
    this.chooseMenu()
    tabService.updateIndex(this, 0)  // tabbar高亮
  }
 chooseMenu(){
        util.request(api.chooseMenu, {
        }, 'GET').then(res => {
          if (res.errno === 0) {
            if(res.data == 1 ) {
               tabService.updateRole(this,'1')
               tabService.updateIndex(this, 2)  //由于tabService.updateRole(this,'1')为1，所有少一个认养tabbar，所有updateIndex应传2高亮
            }else {
               tabService.updateRole(this,'0')
               tabService.updateIndex(this, 3) 
            }
          }
          else{
            util.showErrorToast(res.errmsg);
          }
        })
      }