How can I get the JSON array data from nsstring or byte in xcode 4.2?

Question

I'm trying to get values from nsdata class and doesn't work.

here is my JSON data.

{
    "count": 3,
    "item": [{
        "id": "1",
        "latitude": "37.556811",
        "longitude": "126.922015",
        "imgUrl": "http://175.211.62.15/sample_res/1.jpg",
        "found": false
    }, {
        "id": "3",
        "latitude": "37.556203",
        "longitude": "126.922629",
        "imgUrl": "http://175.211.62.15/sample_res/3.jpg",
        "found": false
    }, {
        "id": "2",
        "latitude": "37.556985",
        "longitude": "126.92286",
        "imgUrl": "http://175.211.62.15/sample_res/2.jpg",
        "found": false
    }]
}

and here is my code

-(NSDictionary *)getDataFromItemList
{

    NSData *dataBody = [[NSData alloc] initWithBytes:buffer length:sizeof(buffer)]; 
    NSDictionary *iTem = [[NSDictionary alloc]init];
    iTem = [NSJSONSerialization JSONObjectWithData:dataBody options:NSJSONReadingMutableContainers error:nil];
    NSLog(@"id = %@",[iTem objectForKey:@"id"]);

    //for Test
    output = [[NSString alloc] initWithBytes:buffer length:rangeHeader.length encoding:NSUTF8StringEncoding];
    NSLog(@"%@",output);
    return iTem;

}

how can I access every value in the JSON? Please help me.

Solution 1

Try JSONKit for this. Is is extremely simple to use.

Solution 2

I did it by using the framework : http://stig.github.com/json-framework/

It is very powerfull and can do incredible stuff !

Here how I use it to extract an item name from an HTTP request : (where result is the JSO string)

NSString *result = request.responseString;

jsonArray = (NSArray*)[result JSONValue]; /* Convert the response into an array */

NSDictionary *jsonDict = [jsonArray objectAtIndex:0];

/* grabs information and display them in the labels*/
name = [jsonDict objectForKey:@"wine_name"];

Hope this will be helpfull

Solution 3

Looking at your JSON, you are not querying the right object in the object hierarchy. The top object, which you extract correctly, is an NSDictionary. To get at the items array, and the single items, you have to do this.

NSArray *items = [iTem objectForKey:@"item"];
NSArray *filteredArray = [items filteredArrayUsingPredicate:
   [NSPredicate predicateWithFormat:@"id = %d", 2];
if (filteredArray.count) NSDictionary *item2 = [filteredArray objectAtIndex:0];

Comments

[Mundi]

Where did you get @"wine_name" from?

[Edelweiss]

This is a key in my JSON string {"wine_name":"some wine name"}

[Mundi]

But what does that have to do with the question? He already extracted the NSDictionary correctly from the JSON... Never mind.

[Mundi]

How about the other log statements? Trace back with logs and find out what is nil. Maybe your input string? This is how you will find the error.