Vue ---在for循环修改页面中某个值，页面没有及时刷新问题（使用this.$forceUpdate()解决）

export default {
  data() {
    return {
      dataList:[],
    };
  },
  methods: {
    getData() {
      var _this = this;
      var dataList = [];
      dataList = response.data.data;

      for(var i=0;i<dataList.length;i++){
         _this.downloadBase64(dataList[i].fielID, i, dataList);
      }

    },
    downloadBase64(fielID, i, dataList) {
        var vm = this;
        $.ajax({
            url: AppInter.downloadBase64,
            asysc: true,
            data: {
                fileName: ‘1.jpg‘,
                fileId: fielID
            },
            cache: !0,
            timeout: 2e4,
            dataType: "json",
            type: "POST",
            xhrFields: {
                withCredentials: !0
            },
            crossDomain: !0,
            contentType: "application/x-www-form-urlencoded;charset=UTF-8",
            beforeSend: function () {
                vm.loading = weui.loading();
            },
            success: function (response) {
                if (response.responseCode == ‘0‘) {
                    dataList[i].picUrl = ‘data:image/jpg;base64,‘ + response.data;
                    vm.dataList = dataList;
                    vm.$forceUpdate();
                } else {
                    weui.alert("请求错误，请稍候再试", function () {}, {
                        title: ‘温馨提示‘
                    });
                }
            },
            error: function (xhr, msg, err) {
                weui.alert("请求失败，请稍候再试", function () {}, {
                    title: ‘温馨提示‘
                });
            },
            complete: function () {
                if (vm.loading.hide) {
                    vm.loading.hide();
                }
            }
        })
    }
    
  },
  created() {
      
  },
  mounted() {
    
  }
};