NSJSONSerialization - key names from array - iphone

Question

I am parsing JSON data using objective-c.
The data is as follows:
{"parcels":{"12595884967":{"kj_number":"KJ6612636902","recipient":"Krzysztof Racki","courier":"3"}}}
I have an object "parcels" which has keys for packages. Now while I dont have a problem extracting this using JSONSerialization class, I am stuck figuring how to get a key name (i mean, how to read value 12595884967 from code).
Code:
if ( [ NSJSONSerialization isValidJSONObject:jsonObject ] ) {
// we are getting root element, the "parcels"
NSMutableSet* parcels = [ jsonObject mutableSetValueForKey:#"parcels" ];
// get array of NSDictionary*'ies
// in this example array has single NSDictionary* element with flds like "kj_number"
NSArray* array = [ parcels allObjects ];
for ( int i = 0 ; i < [ array count ] ; ++i ) {
NSObject* obj = [ array objectAtIndex: i ];
// the problem: how i get this dictionary KEY? string value of 12595884967
// how I should get it from code here?
// like: number = [ obj name ] or maybe [ obj keyName ]
if ( [ obj isKindOfClass:[ NSDictionary class ] ] ) {
// this always evaluates to true
// here we do reading attributes like kj_number, recipient etc
// and this works
}
}
}
for example in java it was:
JSONObject json = response.asJSONObject();
JSONObject parcels = json.getJSONObject( "parcels" );
#SuppressWarnings("unchecked")
Iterator<String> it = parcels.keys();
while ( it.hasNext() ) {
String key = it.next(); // value of 12595884967
Object value = parcel.getObject( key ); // JSONObject ref with data
}

Answer 1

A set doesn't store keys. You want to get a dictionary from the json.
NSDictionary* parcels = [jsonObject objectForKey:#"parcels"];
// get the keys
NSArray *keys = [parcels allKeys];
for (NSString *key in keys) {
NSDictionary *parcel = [parcels objectForKey:key];
// do something with parcel
}
Getting the keys in an array first is optional, you could iterate over the parcels dictionary directly: for (NSString *key in parcels) {.

Answer 2

I would propose to use a NSDictionary instead of NSMutableSet.
The NSDictionary has a method allKeys that will provide you with the requested data.