微信小程序实现简单的select下拉框

<view class="item">
 <label class="first"><text>*</text>公司/商户类型：</label>
 <!-- 通过点击事件改变图片的旋转角度、自定义下拉框的高度 -->
 <view class="value" bindtap="select">
 <view style="display:inline-block;">{{type!=''?type:'选择商户类型'}}</view>
 <image src="../img/sj@2x.png" class="sanjiao" style="{{isSelect?'transform:rotateZ(180deg)':''}}"/>
 <!-- select -->
 <view class="select" style="{{isSelect?'height:'+54*types.length+'rpx;':'border:0'}}">
 <view class="type" catchtap="getType" wx:for="{{types}}" data-type="{{item}}" wx:key="type">{{item}}</view>
 </view>
 </view>
</view>

.sanjiao{
 width: 18rpx;
 height: 10rpx;
 margin-left: 20rpx;
 transition: 0.5s;/* 选转图片过渡 */
}
.select{
 position: absolute;
 z-index: 10;
 border: 2rpx solid #aaaaaa;
 padding: 0 8rpx;
 top:46rpx;
 left: -10rpx;
 width: 210rpx;
 overflow: auto;
 height: 0;
 max-height: 200rpx;
 background-color:#fff;
 box-sizing: border-box;
 transition: height 0.5s;/* 高度变换过渡 */
}
.select .type{
 color: #aaaaaa;
 border-top: 2px solid #dadada;
 padding: 6rpx;
}
.select :first-child{
 border: 0;
}

data: {
 isSelect:false,//展示类型？
 types:['类型一','类型二'],//公司/商户类型
 type:"",//公司/商户类型
 },
 //点击控制下拉框的展示、隐藏
 select:function(){
 var isSelect = this.data.isSelect
 this.setData({ isSelect:!isSelect})
 },
 //点击下拉框选项，选中并隐藏下拉框
 getType:function(e){
 let value = e.currentTarget.dataset.type
 this.setData({
 type:value ,
 isSelect: false,
 })
 },