Gathering data with JSON

Question

When I use the google JSON API, the format given is not similar to the one on TreeHouse. 
for TreeHouse we have:
'''json
{
...
...
-post: [...]
}
'''
But for the Google JSON search API we have:
'''json
-responseData: {
      -results: [ { ... } ]
      ...
      ...
}
'''
for the Google search API we have the results nested by responseData which is giving me a runtime error:
unrecognized selector sent to instance
and it points to this line of code:
NSDictionary *blogPosts = [self.blogPosts objectAtIndex:indexPath.row];
I've implemented to code to fetch the information like this:
NSURL *blogUrl = [NSURL URLWithString:@"https://ajax.googleapis.com/ajax/services/search/web?v=1.0&q=richard"];
NSData *jsonData = [NSData dataWithContentsOfURL:blogUrl];
NSError *error = nil;
NSDictionary *dataDictionary = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error];
self.blogPosts = [dataDictionary objectForKey:@"responseData"];
How would I be able to get around that?

Stone Preston · Accepted Answer

hmm what I think is happening  is that your are setting your blogPosts property to this:
self.blogPosts = [dataDictionary objectForKey:@"responseData"];
however that responseData key is another dictionary, not an array as you can see here:
responseData: { -results: [ { ... } ] ... ... }
its got keys and values inside it. so your self.blogPosts property now holds a dictionary, which would be why it does not respond to the objectAtIndex method (which is called on arrays, not dictionaries) and why you are getting that unrecognized selector error. 
To remedy this, you would need to set your self.blogPosts property to an array thats within that responseData dictionary.

Joan Guerra Makaren · Answer

Excellent solution @Richard Lu (https://teamtreehouse.com/xinghuilu) i dit and worked for me too, now the biggest issue is that those search results only shows the first 4 results

Akib Quraishi · Answer

Stone Preston & Xing = My Code is Running...
[self.thanks]

Richard Lu · Answer

Thanks, I took your advice and I saved the dictionary onto a new dictionary thats within the responseData dictionary:
Incase anybody else encounters this issue in the future here's what I did:
dataDictionary = [dataDictionary objectForKey:@"responseData"];
self.blogPosts = [dataDictionary objectForKey:@"results"];
instead of just doing:
self.blogPost = [dataDictionary objectForKey:@"responseData"];

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Richard Lu

Richard Lu

Gathering data with JSON

4 Answers

Stone Preston

Stone Preston

Richard Lu

Richard Lu

Akib Quraishi

Akib Quraishi

Joan Guerra Makaren

Joan Guerra Makaren