如何创建从AWS下载的图像数组？

Question

场景：我在同一个游戏中拥有一个包含多个用户的游戏。每个用户都可以获得积分。当轮到我时，我希望他们的图像显示在imageView中。

每个用户都可以选择添加自己的图像（保存到AWS），但如果用户没有图像，则会为其分配默认图像。

问题：我能够成功创建一系列图片，但我有两个问题：

1. 在完成下载块之前，为存储了图像的用户分配默认图像。下载完成后，其图像将更改为其存储的图像。
2. 当用户添加新图片时，他们的图片永远不会更新。尽管AWS仅具有更新的图像，但它显示了之前添加的图像。

代码：

-(void)getUserImagesFromServer {

self.userPlayerImages = [NSMutableArray array];

for (NSString *userId in self.playerUserIds) {

    // Construct the NSURL for the download location.
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:userId];
    NSURL *downloadingFileURL = [NSURL fileURLWithPath:filePath];

    // Construct the download request.
    AWSS3TransferManagerDownloadRequest *downloadRequest = [AWSS3TransferManagerDownloadRequest new];
    downloadRequest.bucket = @"boxscore-user-pictures";
    downloadRequest.key = userId;
    downloadRequest.downloadingFileURL = downloadingFileURL;

    [self downloadRequest:downloadRequest:^(BOOL finished) {
        if(finished){

            if (self.tempResultCount == 1) {
                [self.userPlayerImages addObject: [UIImage imageWithContentsOfFile:filePath]];
            } else {
                [self.userPlayerImages addObject:self.tempPlayerImage];
            }
        }
    }];
}
}

-(void) downloadRequest:(AWSS3TransferManagerDownloadRequest *)downloadRequest :(myCompletion) compblock{

AWSS3TransferManager *transferManager = [AWSS3TransferManager defaultS3TransferManager];

__block int taskResult;
// Download the file.
[[transferManager download:downloadRequest] continueWithExecutor:[AWSExecutor mainThreadExecutor]
                                                       withBlock:^id(AWSTask *task) {
                                                           if (task.error){

                                                               NSLog(@"Error: %@", task.error);
taskResult = 0;

                                                           } else {
                                                               NSLog(@"Successfully downloaded Image!");
taskResult = 1;

                                                           }
                                                           self.tempResultCount = taskResult;

                                                           return nil;
                                                       }];


compblock(YES);
}

视觉参考用户界面：



更新

以下是用于将图像保存到AWS的代码：

-(void)saveImageToServer:(UIImage*)image {

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:[NSString stringWithFormat:@"%@",[self.sud objectForKey:@"userId"]]];
[UIImagePNGRepresentation(image) writeToFile:filePath atomically:YES];

NSURL *fileUrl = [NSURL fileURLWithPath:filePath];

AWSS3TransferManagerUploadRequest *uploadRequest = [AWSS3TransferManagerUploadRequest new];
uploadRequest.bucket = @"boxscore-user-pictures";
uploadRequest.key = [NSString stringWithFormat:@"%@",[self.sud objectForKey:@"userId"]];
uploadRequest.body = fileUrl;

AWSS3TransferManager *transferManager = [AWSS3TransferManager defaultS3TransferManager];

[[transferManager upload:uploadRequest] continueWithExecutor:[AWSExecutor mainThreadExecutor]
                                                   withBlock:^id(AWSTask *task) {
                                                       if (task.error) {
                                                           if ([task.error.domain isEqualToString:AWSS3TransferManagerErrorDomain]) {
                                                               switch (task.error.code) {
                                                                   case AWSS3TransferManagerErrorCancelled:
                                                                   case AWSS3TransferManagerErrorPaused:
                                                                       break;
                                                                   default:
                                                                       NSLog(@"Error: %@", task.error);
                                                                       break;
                                                               }
                                                           } else {
                                                               // Unknown error.
                                                               NSLog(@"Error: %@", task.error);
                                                           }
                                                       }
                                                       if (task.result) {
                                                           AWSS3TransferManagerUploadOutput *uploadOutput = task.result;
                                                           // The file uploaded successfully.
                                                       }
                                                       return nil;
                                                   }];

}