微信小程序swiper高度自适应

<view class='swiper'>
    <swiper indicator-dots="{{indicatorDots}}" vertical="{{vertical}}" autoplay="{{autoplay}}" duration="{{duration}}" interval='{{interval}}' bindchange="bindchange"  circular="{{circular}}" style="height:{{imgheights[current]}}rpx;">
    <block wx:for='{{imgList}}' wx:key="{{index}}">
      <swiper-item>
        <image src="{{item}}" data-id='{{index}}' class="slide-image" mode="widthFix" bindload="imageLoad"/>
      </swiper-item>
      </block>
    </swiper>
  </view>

.swiper image {
  width: 100%;
  height: auto;
}

data: {
    //图片地址
    imgList: ['/images/wyh-img_bg.png', '/images/wyh-img8.png', '/images/wyh-img_shop1.png', '/images/wyh-img_bg1.png'],
    //是否采用衔接滑动  
    circular: true,
    //是否显示画板指示点  
    indicatorDots: false,
    //选中点的颜色  
    indicatorcolor: "#000",
    //是否竖直  
    vertical: false,
    //是否自动切换  
    autoplay: true,
    //自动切换的间隔
    interval: 2500,
    //滑动动画时长毫秒  
    duration: 100,
　　
    //所有图片的高度  （必须）
    imgheights: [],
    //图片宽度 
    imgwidth: 750,
    //默认  （必须）
    current: 0   
  },
imageLoad: function (e) {//获取图片真实宽度  
    var imgwidth = e.detail.width,
      imgheight = e.detail.height,
      //宽高比  
      ratio = imgwidth / imgheight;
      console.log(imgwidth, imgheight)
    //计算的高度值  
    var viewHeight = 750 / ratio;
    var imgheight = viewHeight;
    var imgheights = this.data.imgheights;
    //把每一张图片的对应的高度记录到数组里  
    imgheights[e.target.dataset.id] = imgheight;
    this.setData({
      imgheights: imgheights
    })
  },
  bindchange: function (e) {
    // console.log(e.detail.current)
    this.setData({ current: e.detail.current })
  },