How to output data using NSJSONSerialization?

Question

I'm trying to output some data using NSJSONSerializationusing the code below.

This log statement works NSLog(@"publicData: %@", publicData); but then it crashes when I try to get the "description" of the dictionary NSLog(@"data: %@", [dict objectForKey:@"description"]);

my error message: unrecognized selector sent to instance. Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFDictionary objectAtIndex:]: unrecognized selector sent to instance...'

I've included the NSLog output.

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL
                                                          URLWithString:@"http://******.com/api/feed"]];

NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];

NSError *jsonParsingError = nil;
NSArray *publicData = [NSJSONSerialization JSONObjectWithData:response options:0 error:&jsonParsingError];

NSLog(@"data from publicData: %@", publicData);
NSDictionary *dict;

for(int i=0; i<[publicData count];i++)
{
    dict= [publicData objectAtIndex:i];
    NSLog(@"data: %@", [dict objectForKey:@"description"]);

}


publicData: {
data =     (
            {
        address =             {
     address = "street address";
            city = cityname;
            lat = "42.000237034667";
            lng = "12.492805660226";
            province = provincename;
        };
        "category_id" = 20;
        description = "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum";
        id = 1;
        slug = "title-in-en";
        title = "title in En";
    },
            {
        address =             {
            address = "street address";
            city = cityname;
            lat = "42.000237034667";
            lng = "12.492805660226";
            province = provincename;
        };
        "category_id" = 20;
        description = "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum";
        id = 5;
        slug = "title-in-en";
        title = "title in En";
    },

thanks for any help

In your case, publicData is an NSDictionary with a single object for key "data", not an array. Access an NSDictionary with objectForKey, not objectAtIndex. — Marcus Adams
– Marcus Adams, Commented May 29, 2013 at 19:10
@MarcusAdams I thought I was doing that though. Where "dict" is the dictionary and publicData is the nsarray. Is that incorrect? thanks! NSDictionary *dict; for(int i=0; i<[publicData count];i++) { dict= [publicData objectAtIndex:i]; NSLog(@"data: %@", [dict objectForKey:@"description"]); } — hanumanDev
– hanumanDev, Commented May 29, 2013 at 19:22

danypata · Accepted Answer · 2013-05-29 19:23:51Z

1

I optimized a little the code provided by codeplasma and it's looking like this:

 NSDictionary *publicData =  [NSJSONSerialization JSONObjectWithData:response
                                                                options:0              
                                                                  error:&jsonParsingError];
    NSArray *objects = [publicData objectForKey:@"data"];
    for(NSDictionary *element in objects) {
       NSLog(@"the description is %@",[element objectForKey:@"description"]);
    }

Your publicData is NSDictionary not NSArray.

edited May 29, 2013 at 19:23

answered May 29, 2013 at 19:09

danypata

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4 Comments

hanumanDev Over a year ago

thanks but I'm getting an NSArray has no method 'objectForKey' error.

danypata Over a year ago

@hanumanDev can you post the full JOSN structure without your NSLog, maybe from your borwser :)

hanumanDev Over a year ago

I just edited my question above and added the output from the browser. thanks for the help!

hanumanDev Over a year ago

that worked perfectly! I was using an array instead of a dictionary. thanks again!

codeplasma · Accepted Answer · 2013-05-29 18:56:09Z

0

I don't know if this will work, but you should try to replace your for loop with this:

for(int i=0; i<[[publicData objectForKey:@"data"] count];i++)
{
    dict= [[publicData objectForKey:@"data"] objectAtIndex:i];
    NSLog(@"data: %@", [dict objectForKey:@"description"]);

}

answered May 29, 2013 at 18:56

codeplasma

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