Return Result of Completion Block

Question

So I\'m trying to build a layer on top of the Twitter API (among others) for a project and I need to find a way to return the result of the Twitter actions to the layer of a

Answer 1

Why don't you also use a block to return the response? Something like:

-(void)sendTweet:(Tweet *)tweet withResponseCallback:(void (^)(NSMutableDictionary *responseDictionary))callback {

    NSLog(@"Sending tweet");

    NSMutableDictionary *twitterRequestDictionary = [[NSMutableDictionary alloc] init];
    [twitterRequestDictionary setObject:tweet.tweetBody forKey:@"status"];

    TWRequest *request = [[TWRequest alloc] initWithURL:[NSURL URLWithString:@"https://api.twitter.com/1/statuses/update.json"]
                                             parameters:twitterRequestDictionary
                                          requestMethod:TWRequestMethodPOST];
    [request setAccount:self.userAccount];


    [request performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {
        NSMutableDictionary *responseDictionary  = [NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableContainers error:nil];
        NSLog(@"Response dictionary: %@", responseDictionary);
        callback(responseDictionary);
    }];
}

Answer 2

Since you are using the asynchronous method it is difficult to say when your method will return the data. So you can consider other options to return the result. For example it might be useful to post a notification, send a message, set some property or even show an alert view.

As for the article' code sample I would try something like the following

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    NSData *data = [self loadDataWithConditionLock];
    dispatch_async(dispatch_get_main_queue(), ^{
        [self updateUIWithData:data];
    });
});