ImagePicker

/***
 * 上传多张图片
 * @param params: 服务器上传图片api所需参数
 * @param filePaths: 通过拍照或者相册拿到的本地图片url数组
 * @returns {Observable}: 服务器返回的图片url
 */
 uploadImages(params: any, filePaths: Array<string>):Observable<any> {
 var options: FileUploadOptions = {
 fileKey: 'filedata',
 fileName: 'avatar.jpg',
 chunkedMode: false,
 mimeType : "image/jpeg",
 params: params
 };
 //每个图片上传任务创建一个信号
 var observables: Array<any> = [];
 for (var i = 0; i < filePaths.length; ++i) {
 let filePath = filePaths[i];
 var observable = new Observable((sub:any) => {
 const fileTransfer = new Transfer();
 let url = '图片上传url';
 fileTransfer.upload(filePath, url, options)
 .then((data: FileUploadResult) => {
 if (200 === data.responseCode) {
 var response = JSON.parse(data.response);
 // 图片上传成功,后台会返回一个图片imageUrl字符串
 var imageUrl = response.data;
 // 将该url发送出来
 sub.next(imageUrl);
 sub.complete();
 } else {
 sub.error('上传图片失败!');
 }
 }, (error) => {
 sub.error(error);
 });
 });
 observables.push(observable);
 }
 return ForkJoinObservable.create(observables);
 }