Question

I m trying to parse json returned by twitter. The json is retrieved well and i convert it to NSDictionary,

NSLog on dictionary object works well and shows all the tweets.

NSLog(@"Twitter response: %@", dict);

but getting following error when i try to get objectForKey for any key in dict object:

2012-02-07 15:35:28.988 TestTweetApp[1525:12103] -[__NSCFArray
objectForKey:]: unrecognized selector sent to instance 0x6a2a370
[Switching to process 1525 thread 0x12103] [Switching to process 1525
thread 0x12103] 2012-02-07 15:35:28.997 TestTweetApp[1525:12103] *
Terminating app due to uncaught exception
‘NSInvalidArgumentException’, reason: ‘-[__NSCFArray objectForKey:]:
unrecognized selector sent to instance 0x6a2a370’
* First throw call stack: (0x176e052 0x1a40d0a 0x176fced 0x16d4f00 0x16d4ce2 0x3044 0xd306 0x2048445 0x2049ecf 0x2049d28 0x20494af
0x9ca1fb24 0x9ca216fe) terminate called throwing an
exceptionsharedlibrary apply-load-rules all

code for viewDidLoad() function is:

- (void)viewDidLoad
{
    [super viewDidLoad];

    TWRequest *request = [[TWRequest alloc] initWithURL:[NSURL URLWithString: @"https://api.twitter.com/1/statuses/public_timeline.json?screen_name=[SOME_USER_NAME]&include_entities=true"] parameters:nil requestMethod:TWRequestMethodGET];

    [request performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error)
    {
        if ([urlResponse statusCode] == 200) 
        {
            NSError *error;  

            NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:responseData options:0 error:&error];

            NSLog(@"Twitter response: %@", [dict objectForKey:@"entities"]);
        }
        else
            NSLog(@"Twitter error, HTTP response: %i", [urlResponse statusCode]);
    }];

}

Answer 1

It seems that your response is a NSArray instead of a NSDictionary. Try

NSLog(@"%@", [NSJSONSerialization JSONObjectWithData:responseData options:0 error:&error]);

before your

NSDictionary *dict... 

line and see the format.
Then move it to an NSArray and access the elements properly.

NSArray *response = [NSJSONSerialization JSONObjectWithData:responseData options:0 error:&error];
NSLog(@"elements = %@", response);