wxml:











 

wxss:

page{
 display: flex;
 flex-direction: column;
 height: 100%;
}
.navbar{
 flex: none;
 display: flex;
 background: #fff;
}
.navbar .item{
 position: relative;
 flex: auto;
 text-align: center;
 line-height: 80rpx;
}
.navbar .item.active{
 color: #FFCC00;
}
.navbar .item.active:after{
 content: "";
 display: block;
 position: absolute;
 bottom: 0;
 left: 0;
 right: 0;
 height: 4rpx;
 background: #FFCC00;
}

 

js:      

var app = getApp()
Page({
 data: {
   navbar: ['首页', '搜索', '我'],
   currentTab: 0
 },
 navbarTap: function(e){
   this.setData({
     currentTab: e.currentTarget.dataset.idx
   })
 }
})