uniCloud.uploadFile上传图片时，浏览器上传正常。APP上传一直不成功。

uniCloud.uploadFile上传图片时，浏览器上传正常。APP上传一直不成功。代码如下：

chooseImg(){  
                uni.chooseImage({  
                    count: 3, //默认9                  
                    success: res=> {  
                        this.imgList=res.tempFilePaths;   
                        this.imgName=res.tempFiles;  
                        this.uploadFile(this);  //上传封面三图  
                    }  
                });  
            },

uploadFile(a){  
                let that=this;  
                that.picAddress=[];  

            for(let i=0;i<a.imgList.length;i++){  
                uniCloud.uploadFile({  
                        filePath:a.imgList[i],  
                        cloudPath: a.imgName[i].name,  
                        onUploadProgress: function(progressEvent){  
                                    console.log(progressEvent);                   

                                    var percentCompleted = Math.round(  
                                   (progressEvent.loaded * 100) / progressEvent.total);  
                                  },  
                                success: (res) => {  
                                    //console.log(res.fileID);  
                                    //that.picAddress=res.fileID;  
                                    //that.picAddress=res.fileID;  
                                    that.picAddress.push(res.fileID);  
                                },  
                                fail() {  
                                    // console.log(res.result);  
                                    uni.showToast({  
                                        title:"上传文件失败"                                    
                                    })  
                                },  
                                complete() {  
                                    console.log(that.picAddress);  
                                }  
                            });  
                        }         
                },