Question

I’m new to JSON and web services so bear with me. I am getting back a response from a web server. In PostMan, it looks something like:

{
    "Response": {
        "TranscriptSource": "MD",
        "Result": [
            {
                "Variant": {
                    "Chromosome": "chr1",
                    "Position": 13302,
                    "ReferenceAllele": "C",
                    "VariantAlleles": "T"
                }
            }
        ],
        "JobId": 0
    }
}

And if in my connectionDidFinishLoading method, I do this:

NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:self.receivedData options:kNilOptions error:&error];
[dict enumerateKeysAndObjectsUsingBlock:^(id obj, id key, BOOL *stop) {
    NSLog(@"key: %@ obj: %@\n", [key description], [obj description]);
}];

I get the same output. Basically I want what’s in that “Variant” field. So I thought I would start by doing

id result = [dict objectForKey@"Result"];

When I step through the debugger, result is nil. I wasn’t sure why since I can print it out.

In the end my main question is, how do I get access to the Variant part of the response, but if you know why id result would be nil, that would also be cool. Thanks!

Answer 1

Your top-level item is an object with a single key, “Response”. It looks like you want:

id result = [[dict objectForKey:@"Response"] objectForKey:@"Result"];