Question

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I created a web service which returns JSON or so I think. The data returned look like this:

{"invoice":{"id":44,"number":42,"amount":1139.99,"checkoutStarted":true,"checkoutCompleted":true}}

To me, that looks like valid JSON.

Using native JSON serializer in iOS5, I take the data and capture it as a NSDictionary.

NSError *error;
    NSDictionary *json = [NSJSONSerialization JSONObjectWithData:[request responseData] options:kNilOptions error:&error];
    NSLog(@"json count: %i, key: %@, value: %@", [json count], [json allKeys], [json allValues]);

The output of the log is:

json count: 1, key: (
    invoice
), value: (
        {
        amount = "1139.99";
        checkoutCompleted = 1;
        checkoutStarted = 1;
        id = 44;
        number = 42;
    }
)

So, it looks to me that the JSON data has a NSString key “invoice” and its value is NSArray ({amount = ..., check...})

So, I convert the values to NSArray:

NSArray *latestInvoice = [json objectForKey:@"invoice"];

But, when stepping through, it says that latestInvoice is not a CFArray. if I print out the values inside the array:

for (id data in latestInvoice) {
        NSLog(@"data is %@", data);
    }

The result is:

data is id
data is checkoutStarted
data is ..

I don’t understand why it only return the “id” instead of “id = 44”. If I set the JSON data to NSDictionary, I know the key is NSString but what is the value? Is it NSArray or something else?

This is the tutorial that I read:
http://www.raywenderlich.com/5492/working-with-json-in-ios-5

Edit: From the answer, it seems like the “value” of the NSDictionary *json is another NSDictionary. I assume it was NSArray or NSString which is wrong. In other words, [K,V] for NSDictionary *json = [@”invoice”, NSDictionary]

Answer 1

The problem is this:

NSArray *latestInvoice = [json objectForKey:@"invoice"];

In actual fact, it should be:

NSDictionary *latestInvoice = [json objectForKey:@"invoice"];

…because what you have is a dictionary, not an array.