<scroll-view scroll-x="true" style="width: 100%;white-space:nowrap;">
 <!-- tab -->
 <view class="tab">
  <view class="tab-nav" style='font-size:12px'>
  <view wx:for="{{tabnav.tabitem}}" bindtap="setTab" data-tabindex="{{index}}" style="min-width:20%;max-width:20%;text-align:center;height: 80rpx;
{{index>4?'border-bottom: 1rpx dotted #ddd;':''}}">{{item.text}}</view>
  <view >
  <view class="tab-line" style="width:{{100/tabnav.tabnum}}%;transform:translateX({{100*showtab}}%);"></view>
  </view>
  </view>
 </view>
</scroll-view>

.tab{
 display: flex;
 flex-direction: column;
}
.tab-nav{
 height: 80rpx;
 background: #fff;
 border-bottom: 0.5rpx dotted #ddd;
 display: flex;
 line-height: 79rpx;
 position: relative;
}
  
.tab-line{
 position: absolute;
 left: 0;
 bottom: -1rpx;
 height: 4rpx;
 background: #f7982a;
 transition: all 0.3s;
}
.tab-content{
 flex: 1;
 overflow-y: auto;
 overflow-x: hidden;
}

import util from './../../utils/util.js';
Page({
 data: {
 showtab: 0, //顶部选项卡索引
 tabnav: {
  tabnum: 5,
  tabitem: [
  {
   "id": 0,
   "text": "商品分类1"
  },
  {
   "id": 1,
   "text": "商品分类2"
  },
  {
   "id": 2,
   "text": "商品分类3"
  },
  {
   "id": 3,
   "text": "商品分类4"
  },
  {
   "id": 4,
   "text": "商品分类5"
  },
  {
   "id": 5,
   "text": "商品分类6"
  },
  {
   "id": 6,
   "text": "商品分类7"
  }
  ]
 },
 productList: [],
 },
 onLoad: function () {
 },
 setTab: function (e) {
 const edata = e.currentTarget.dataset;
 this.setData({
  showtab: edata.tabindex,
   
 })
 },
})