CODEWITHSUNDEEP
objective-cioscocoa-touchios5nsdictionary
Firdous
Firdous

Reputation: 4652

Unable to parse json

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]);
    }];

}

Upvotes: 1

Views: 1110

Answers (2)

Niraj
Niraj

Reputation: 171

If you are unsure about the response format or may have multiple possible response formats and if you also need to handle errors, you may use any of the introspection methods like isKindOfClass or respondsToSelector to determine the type returned by JSONObjectWithData

id responseData = [NSJSONSerialization JSONObjectWithData:responseData options:0 error:&error];

if([responseData respondsToSelector:@selector(objectForKey:)]){
   //Response is of type NSdictionary
   NSLog(@"Twitter response: %@", [responseData objectForKey:@"entities"]);
}else if ([responseData respondsToSelector:@selector(objectAtIndex:)]){
        //Response is of type NSArray
      }
      else{
         // error 
      }

Upvotes: 2

Alexander
Alexander

Reputation: 8147

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);

Upvotes: 2

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