dataTaskWithRequest 问题（目标 c）

Question

I´m making a little app for ios and i need to get some json data. The problem is that I don´t know how to make the request properly. I´m trying the following code, but "response" is always nil, not sure why:

-(instancetype) initWithMatchURL:(NSString*) urlFixtureJSON {
self = [super init];
if(self)
{
    NSURLRequest * request = [NSURLRequest requestWithURL: [NSURL URLWithString: urlFixtureJSON]];

    __block NSData * response = [NSData new];

    NSURLSessionConfiguration * sessionConfiguration = [NSURLSessionConfiguration defaultSessionConfiguration];
    sessionConfiguration.HTTPAdditionalHeaders = @{
                                                   @"Accept"    : @"application/json",
                                                   @"api-key"   : @"<redacted>"
                                                   };

    NSURLSession *session = [NSURLSession sessionWithConfiguration: sessionConfiguration];

    NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:
                                  ^(NSData *dataTask, NSURLResponse *responseTask, NSError *errorTask)
    {
        response = [NSData dataWithData: dataTask];      
    }];

    [task resume];

    NSLog(@"%@", response);
    ...
}

Thanks in advance

Answer 1

Response will always be nil because the code within the block is executed asynchronously (so it happens in the future after the log has been written). If you moved the logging to below response = [...] it would work.