微信小程序滚动选择器怎么做的

<view class="page">

  <view class="page__hd">

    <text class="page__title">picker</text>

    <text class="page__desc">选择器</text>

  </view>

  <view class="page__bd">

    <view class="section">

      <view class="section__title">地区选择器</view>

      <picker bindchange="bindPickerChange" value="{{index}}" range="{{array}}">

        <view class="picker">

          当前选择：{{array[index]}}

        </view>

      </picker>

    </view>

    <view class="section">

      <view class="section__title">时间选择器</view>

      <picker mode="time" value="{{time}}" start="09:01" end="21:01" bindchange="bindTimeChange">

        <view class="picker">

          当前选择: {{time}}

        </view>

      </picker>

    </view>

    <view class="section">

      <view class="section__title">日期选择器</view>

      <picker mode="date" value="{{date}}" start="2015-09-01" end="2017-09-01" bindchange="bindDateChange">

        <view class="picker">

          当前选择: {{date}}

        </view>

      </picker>

    </view>

  </view>

</view>

Page({

  data: {

    array: ['中国', '美国', '巴西', '日本'],

    index: 0,

    date: '2016-09-01',

    time: '12:01'

  },

  bindPickerChange: function(e) {

    console.log('picker发送选择改变，携带值为', e.detail.value)

    this.setData({

      index: e.detail.value

    })

  },

  bindDateChange: function(e) {

    this.setData({

      date: e.detail.value

    })

  },

  bindTimeChange: function(e) {

    this.setData({

      time: e.detail.value

    })

  }

})

.page {

    min-height: 100%;

    flex: 1;

    background-color: #FBF9FE;

    font-size: 32rpx;

    font-family: -apple-system-font,Helvetica Neue,Helvetica,sans-serif;

    overflow: hidden;

}

.page__hd{

    padding: 50rpx 50rpx 100rpx 50rpx;

    text-align: center;

}

.page__title{

    display: inline-block;

    padding: 20rpx 40rpx;

    font-size: 32rpx;

    color: #AAAAAA;

    border-bottom: 1px solid #CCCCCC;

}

.page__desc{

    display: none;

    margin-top: 20rpx;

    font-size: 26rpx;

    color: #BBBBBB;

}

.picker{

  padding: 26rpx;

  background-color: #FFFFFF;

}

.section{

    margin-bottom: 80rpx;

}

.section__title{

    margin-bottom: 16rpx;

    padding-left: 30rpx;

    padding-right: 30rpx;

}