效果：

小程序上传函数 wx.uploadFile(Object object)应该是用了线程发送的,如果遍历上传的话获取到路径后遍历上传的话，会出现异常，因为上传状态没法获取到后台返回的结果

arr是要上传的图片路径数组，arr数组结构为:

[{upload_status: 0, path: "http://tmp/wxa1fd91bd32bf7481.o6zAJswDOgl7nijr8CZf….sUPpf8epWNsZ53771955908686b17d4e2ac93d9a51c9.png"},
{upload_status: 0, path: "http://tmp/wxa1fd91bd32bf7481.o6zAJswDOgl7nijr8CZf….gJWRzXilmRebd35abde6fe5e4b1e5adb6bc73c0a9797.png"}]

src_json结构

var src_json: {
    src_comp: [],
    src_door: [],
    src_business: [],
    src_doc: any[],
    src_product: [],
    src_other: []
}

下面是用for遍历图片数组上传,在上传成功后success函数中修改upload_status状态，但是很遗憾，小程序上传用的是线程发送，这个状态没法改变，因为i会变了，不是对应哪个图片的i

upload: function (key,that,arr, photoType){
    console.log("进入上传函数")
    console.log(arr)
    var len = arr.length
    for (var i = 0; i < len; i++) { //遍历数组，上传图片
      console.log("遍历")
      var upload_task = wx.uploadFile({ //发送上传请求
        url: url + '/survey/' + taskId + "/" + photoType + '/photo',
        filePath: arr[i].path,
        name: "file",
        header: {
          "content-type": "multipart/form-data",
          "authorization": da.data.sessionId
        },
        success: function (res) {
          console.log("上传成功")
          console.log(res.data)
          var data = JSON.parse(res.data) //转化成json
          console.log(data)
          if (data.status == true) {//后台返回的上传成功状态
            console.log("jin")
            console.log(i)
            src_json[key][i].upload_status = 1 //更改当前图片的状态为已上传
          }
        },
        fail: (res) => {
          console.log("上传失败")
          console.log(res.data)
          // stat = 0;
        },
        complete:function(res){
         
        }
      })
    }
  },

这种怎么解决？应该用递归调用函数来解决这个问题，下面是递归函数写法替换for循环：

//index是数组下标索引只，一开始传入是0
//
upload: function(key, index, that, arr, photoType) {
    console.log("进入上传函数")
    console.log(arr)
    var len = arr.length
   
    var upload_task = wx.uploadFile({ //发送上传请求
      url: url + '/survey/' + taskId + "/" + photoType + '/photo',
      filePath: arr[index].path,
      name: "file",
      header: {
        "content-type": "multipart/form-data",
        "authorization": da.data.sessionId
      },
      success: function(res) {
        console.log("上传成功")
        console.log(res.data)

        var data = JSON.parse(res.data)
        console.log(data)
        if (data.status == true) {
          console.log("jin")
          src_json["src_" + key][index].upload_status = 1
          switch (key) { //下面代码是实时更新了图片状态的，每上传一片，就更新一次data的值，这样前端显示图片状态就会改变
            case "comp":
              that.setData({
                src_comp: src_json["src_" + key]
              })
              break
            case "door":
              that.setData({
                src_door: src_json["src_" + key]
              })
              break
            case "business":
              that.setData({
                src_business: src_json["src_" + key]
              })
              break
            case "doc":
              that.setData({
                src_doc: src_json["src_" + key]
              })
              break
            case "product":
              that.setData({
                src_product: src_json["src_" + key]
              })
              break
            case "other":
              that.setData({
                src_other: src_json["src_" + key]
              })
              break
          }
          index++;
          console.log(index)
        }
      },
      fail: (res) => {
        console.log("上传失败")
        console.log(res.data)
        // stat = 0;
      },
      complete: function(res) {//解决循环问题，这里递归调用
        if (index == len) {//当下标索引等于长度，停止递归调用
          console.log(index)
          wx.showToast({
            title: '上传完成',
            icon: 'success',
            duration: 2000
          })
        } else {
           console.log("长度小于数组长度")
          console.log('正在上传第' + index + '张');
          that.upload(key, index, that, arr, photoType) //递归

        }
      }
    })
  }

上传函数的调用：

 that.upload("business", 0, that, up, photoType)