微信小程序 图片宽度自适应的实现

<swiper indicator-dots="{{indicatordots}}" autoplay="{{autoplay}}" interval="{{interval}}" duration="{{duration}}"> 
  <block wx:for="{{imgurls}}" wx:key="image"> 
   <swiper-item> 
     <image src="{{item.image}}" model="aspectfit" style="width: {{imagewidth}}px;" bindload="imageload" /> 
   </swiper-item> 
  </block> 
</swiper> 
 

imageload: function () { 
  this.setdata({ 
   imagewidth: wx.getsysteminfosync().windowwidth,//图片宽度 
 
   imgurls: [ 
     { image: "http://img02.tooopen.com/images/20150928/tooopen_sy_143912755726.jpg" }, 
   { image: "http://img06.tooopen.com/images/20160818/tooopen_sy_175866434296.jpg" }, 
   { image: "http://img06.tooopen.com/images/20160818/tooopen_sy_175833047715.jpg" }], 
   indicatordots: false,//是否显示圆点 
  autoplay: true,//自动播放 
  interval: 2000,//间隔时间 
  duration: 1000//监听滚动和点击事件 
 }) 
}