微信小程序实现select下拉框

<view class="fenlei">
    <!-- 下拉框 -->
    <view class="select_box">
      <view class="select" catchtap="selectTaps">
        <text class="select_text">{{selectDatas[indexs]}</text>
        <image class="select_img:{{shows&&'select_img_rotate'}}"
   src="../../../static/img/lifeCircle/arroundServe/xiala.png"></image>
      </view>
      <view class="option_box" style="height:{{shows?(selectDatas.length>8?890:selectDatas.length*110):0}}rpx;">
        <text class="option-list" wx:for="{{selectDatas}}" wx:key="this" data-index="{{index}}" catchtap="optionTaps"
          style="{{indexs==selectDatas.length-1&&'border:0;'}}">{{item}}</text>
      </view>
    </view>
</view>

/* fenlei */
.fenlei{
  margin: 0 25rpx;
  height: 80rpx;
  line-height: 80rpx;
  display: flex;
  align-items: center;
  background-color:#F5F6F7;
}
.fenlei text{
  font-size: 30rpx;
  color: #999999;
  margin-left: 15rpx;
}
/* 下拉框 */
.select_box {
  width: 100%;
  text-align: left;
  position: relative;
}

.select {
  box-sizing: border-box;
  width: 100%;
  border-radius: 8rpx;
  display: flex;
  align-items: center;
  padding: 0 20rpx;
}

.select_text {
  font-size: 32rpx;
  flex: 1;
  color: #999999;
}

.select_img {
  width: 37rpx;
  height: 30rpx;
  display: block;
  transition: transform 0.3s;
}

.select_img_rotate {
  transform: rotate(180deg);
}

.option_box {
  position: absolute;
  width: 100%;
  box-sizing: border-box;
  border-top: 0;
  background: #fff;
  z-index: 100;
  text-align:center;
  transition: height 0.3s;
  overflow-y: auto;
}

.option-list {
  display: block;
  line-height: 106rpx;
  font-size: 32rpx;
  border-bottom: 1px solid #efefef;
  padding: 10rpx;
  color: rgb(102, 102, 102);
  cursor: pointer;
}

 /**
   * 页面的初始数据
   */
  data: {
    shows: false, //控制下拉列表的显示隐藏，false隐藏、true显示
    selectDatas: ['再生资源回收点', '家政服务点', '综合超市','生鲜超市','邮政快递综合服务点','维修点','照相文印店','美容美发店'], //下拉列表的数据
    indexs: 0, //选择的下拉列 表下标,
  },
// 点击下拉显示框
selectTaps(e) {
  console.log(e)
  this.setData({
    shows: !this.data.shows,
  });
},
// 点击下拉列表
optionTaps(e) {
  let Indexs = e.currentTarget.dataset.index; //获取点击的下拉列表的下标
  console.log(Indexs)
  this.setData({
    indexs: Indexs,
    shows: !this.data.shows
  });
},