-(void)downImage

{

    AlbumInfo *info = [self.dataArray objectAtIndex:index];

    NSString *filePath = [[SandBoxPath pathForCaches]stringByAppendingPathComponent:@"/a.png"];

    [self showLoadingView];

    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:info.url]];

    AFDownloadRequestOperation *downloadOperation = [[AFDownloadRequestOperation alloc]initWithRequest:request targetPath:filePath shouldResume:NO];

    [downloadOperation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {

        [self hideLoadingView];

        UIImage *image = [UIImage imageWithContentsOfFile:filePath];

        if (image) {

            UIImageWriteToSavedPhotosAlbum(image, self, nil, NULL);

            [self showToast:@"保存成功！"];

        }else{

            [self showToast:@"保存失败！"];

        }

    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {

        [self hideLoadingView];

        [self showToast:@"保存失败！"];

    }];

    [downloadOperation setProgressiveDownloadProgressBlock:^(AFDownloadRequestOperation *operation, NSInteger bytesRead, long long totalBytesRead, long long totalBytesExpected, long long totalBytesReadForFile, long long totalBytesExpectedToReadForFile) {

        TTLog(@"bytesread: %d",bytesRead);

    }];

    NSOperationQueue *downloadQueue = [[NSOperationQueue alloc]init];

    [downloadQueue addOperation:downloadOperation];

}