sharefile(e){
    var i = e.currentTarget.dataset.index
    wx.cloud.downloadFile({
      fileID:this.data.list[i].fileID,
      success(res){
              // 下载完成后转发
      console.log(res.tempFilePath)
        wx.shareFileMessage({
          filePath: res.tempFilePath,
          success(res){
            console.log(res)
          },
          fail(err){
            console.log(err)
          }
        })
      }
    })
  },