How can I pull out nested JSON values in a collection in objective-C?
I've got an OData service that can return JSON values for a开发者_Go百科n object collection. I'd like to point an iPhone app at a collection of JSON objects off of that service (results shown below with one sample record).
How can I parse these nested values? When I convert the response string to JSON values, it only grabs "d" (my code for that is also below).
{
"d" : {
"results": [
{
"__metadata": {
"uri": "http://someserver/service.svc/collection(1234L)", "type": "My.Namespace.Type"
}, "Property1": "value1", "Property2": 7274, "Collection1": {
"__deferred": {
"Property3": "http://someserver/service.svc/collection(1234L)/Images"
}
}
},
...
Sample objective C code:
- (void)requestFinished:(ASIHTTPRequest *)request
{
if (request.responseStatusCode == 200)
{
NSString *responseString = [request responseString];
textView.text = responseString;
NSDictionary *responseDict = [responseString JSONValue];
NSArray *keys = [responseDict allKeys];
[self printArray:keys]; // This prints "d"
...
}
}
It seems that you have a root key "d" and all the keys are in fact subkeys, try
NSDictionary *responseDict = [[responseString JSONValue] objectForKey:@"d"];
or even
NSArray *responseArray = [[[responseString JSONValue] objectForKey:@"d"] objectForKey:@"results"];
it's an alternance of NSArray and NSDictionnary :
NSDictionary *responseDict = [[responseString JSONValue] valueForKey:@"d"];
NSArray *responseArray = [responseDict valueForKey:@"results"];
NSDictionary *dict;
for(int i=0; i< [responseArray count]; i++){
dict = [responseArray objectAtIndex:i];
NSLog(@"- %@",[responseArray objectAtIndex:i]);
}
it's always strongly dependant on your JSON generator. So I cannot tell you for sure it's always the best way of digging, but in this case it seems so. Just remember:
- [data1,data2,data3,data4] -> array
- {key1:data1,key2:data2} -> dictionary
From the looks of it, d
is the key to another dictionary that contains they key results
which contains an array with your data. Try using
NSLog(@"%@", responseDict);
to see the whole tree hierarchy.
You can use the json-framework to convert the json data to an NSDictionary
.
use this url http://mobileorchard.com/tutorial-json-over-http-on-the-iphone/
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