<view class='tabBar'><view class='tabItem wx:if="{{tabClick===0?"click":""}}"' bindtap='clickTab' data-index='0'>tab1</view><view class='tabItem wx:if="{{tabClick===1?"click":""}}"' bindtap='clickTab' data-index='1'>tab2 </view><view class='tabItem wx:if="{{tabClick===2?"click":""}}"' bindtap='clickTab' data-index='2'>tab3 </view><view class='underline' animation="{{animationData}}" style='left:{{isLeft}}'></view></view>

.tabBar{height: 80rpx;background-color:#50B7EA;width: 100%;font-size: 28rpx;color: rgba(255,255,255,0.50);position: fixed;top: 0;left: 0;display: flex;justify-content: center;align-items: center;z-index: 997;}.tabItem{width: 33.333%;display: flex;align-content: center;justify-content: center;position: relative;height: 100%;font-size: 28rpx;}.click{color: white;}.underline{position: absolute;content: '';width: 84rpx;height: 3px;background-color:white;bottom: 0;} 

data:{tabClick: 0,animationData: {}, isLeft: '12%'},swiperTab: function (e) {var that = this;var index = e.detail.currentconsole.log(e.detail.current)var animation = wx.createAnimation({duration: 1000,timingFunction: "ease",})this.animation = animationif (index === 0) {animation.translate(0, 0).step();that.setData({animationData: animation.export()})that.setData({tabClick: e.detail.current});} else if (index === 1) {var w = wx.getSystemInfoSync().windowWidth;w = w * 0.32animation.translate(w, 0).step();that.setData({animationData: animation.export()})that.setData({tabClick: e.detail.current});} else if(index === 2){var w = wx.getSystemInfoSync().windowWidth;w = w * 0.65animation.translate(w, 0).step();that.setData({animationData: animation.export()})that.setData({tabClick: e.detail.current});}},