微信小程序 swiper 显示图片计数 当前/总数

<view class="swiperContainer">
  <swiper bindchange="swiperChange"  autoplay="{{autoplay}}"  duration="{{duration}}" style='height: 380rpx;'>
    <block wx:for="{{imgUrls}}" wx:key="*this">
      <swiper-item wx:key="*this">
        <image src="{{item}}" class="slide-image"  class='img'  />
      </swiper-item>
    </block>
  </swiper>
  <view class="imageCount">{{current+1}}/{{imgUrls.length}}</view>
</view>

.swiperContainer {
  position: relative;
}
.img {
   100%;
　height:100%;
}
.imageCount {
  120rpx;
  height:50rpx;
  background-color: rgba(0, 0, 0, 0.3);
  border-radius:40rpx;
  line-height:50rpx;
  color:#fff;
  text-align:center;
  font-size:26rpx;
  position:absolute;
  left:13px;
  bottom:20rpx;
}

Page({ 
  data: {
    duration:"500",
    imgUrls: [
      'https://cdn.cnbj0.fds.api.mi-img.com/b2c-mimall-media/b51889744910df7979a2f672434da84e.jpg?thumb=1&w=720&h=360',
      'https://cdn.cnbj0.fds.api.mi-img.com/b2c-mimall-media/37dfdc929ee9a4313facb0b23ebcd721.jpg?thumb=1&w=720&h=360',
      'https://cdn.cnbj0.fds.api.mi-img.com/b2c-mimall-media/a0ff3dc30027f3b615bfe03f1d306ee5.jpg?thumb=1&w=720&h=360',
      'https://cdn.cnbj0.fds.api.mi-img.com/b2c-mimall-media/2320573b3be643e29f5270a97e1a9c1d.jpg?thumb=1&w=720&h=360'
    ],
    current: 0
  }, 
  swiperChange: function (e) {
    var that = this;
    if (e.detail.source == 'touch') {
      that.setData({
        current: e.detail.current
      })
    }
  }, 
  onLoad: function (options) {
    var that = this; 
  }, 
  onReady: function () {

  }, 
  onShow: function () {

  },
 
  /**
   * 用户点击右上角分享
   */
  onShareAppMessage: function () {

  }
})