<image class="midimage" data-Type="{{item.Type}}" data-BillCode="{{item.BillCode}}" data-src="{{item.imgurl}}"
 src="{{item.imgurl}}" mode="scaleToFill" bindtap="addtaskimg" bindlongtap="imglongtap" ></image>

var objurl= JSON.parse(res.data);
        //重置图片参数
        var temppostionlist=that.data.postionlist;
        for (var i=0;i<temppostionlist.length;i++)
        {
          if (temppostionlist[i]["Type"]==e.currentTarget.dataset.type){           
           temppostionlist[i]["imgurl"]=temppaths;
           temppostionlist[i]["serverimgurl"]=objurl.Body.Data;
           break;
          }            
        } 
        that.setData( {  
             postionlist:temppostionlist  
        })

 <scroll-view class="center" scroll-y="true">
      <view class="midcenter" wx:for="{{postionlist}}">
      <view class="mid_top" >
          <image class="smallimage" src="../images/my/XXH/line_title.png" mode="aspectFit" ></image>
          <text>{{item.KeyValue}}</text>
      </view>
      <view class="mid_center">
          <text>{{item.Remark}}</text>
      </view>
      <view class="mid_bottom">
          <image class="midimage" data-Type="{{item.Type}}" data-BillCode="{{item.BillCode}}" data-src="{{item.imgurl}}"
          src="{{item.imgurl}}" mode="scaleToFill" bindtap="addtaskimg" bindlongtap="imglongtap" ></image>
      </view>      
      </view>
    </scroll-view>

addtaskimg:function(e){   
  //添加选择图片  
  if (this.data.blongtap)
  {
   //处理如果是长按，则不再执行下面的
   this.setData({
    blongtap:false
   });
   return;
  }
  var that = this;
   wx.chooseImage({
    count:1, //默认1张
    success:function(res){
      //先上传至服务器，再返回路径供保存
      var temppaths=res.tempFilePaths[0];//+".jpg";
      wx.uploadFile({
       url:app.globalData.ghost+"YWTask/PutUploadFile?BillCode="+that.data.detail.BillCode+"&ID="+that.data.id,
       filePath:temppaths,
       name:'image',
       formData:{},
       success:function(res){
        //res.data返回的是一个字符串，需进行转换成objcet，wx不识别eval函数
        console.log(res.Data);
        var objurl= JSON.parse(res.data);
        //重置图片参数
        var temppostionlist=that.data.postionlist;
        for (var i=0;i<temppostionlist.length;i++)
        {
          if (temppostionlist[i]["Type"]==e.currentTarget.dataset.type){           
           temppostionlist[i]["imgurl"]=temppaths;
           temppostionlist[i]["serverimgurl"]=objurl.Body.Data;
           break;
          }            
        } 
        that.setData( {  
             postionlist:temppostionlist  
        })        
       }
      })
    }
   })
 }