How to create a json file in iOS?

Question

I have some data and need to create a json file with this structure :

{"eventData":{"eventDate":"Jun 13, 2012 12:00:00 AM","eventLocation":{"latitude":43.93838383,"longitude":-3.46},"text":"hjhj","imageData":"raw data","imageFormat":"JPEG","expirationTime":1339538400000},"type":"ELDIARIOMONTANES","title":"accIDENTE"}

Can Please someone give me some code how to to put my data in a json file with this structure or at least an example on how u make json structures?

EDIT

Ok so i wrote some code :

NSString *jsonString = @"[{\"eventData\":{\"eventDate\":\"Jun 13, 2012 12:00:00 AM\",\"eventLocation\":{\"latitude\":43.93838383,\"longitude\":-3.46},\"text\":\"hjhj\",\"imageData\":\"raw data\",\"imageFormat\":\"JPEG\",\"expirationTime\":1339538400000},\"type\":\"ELDIARIOMONTANES\",\"title\":\"accIDENTE\"}]";

    NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
    NSError *e;
    NSMutableArray *jsonList = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&e];
    NSLog(@"jsonList: %@", jsonList);

jsonList is a json file now ??? And is it in the correct format?? Cause when i print it the output is :

jsonList: (
        {
        eventData =         {
            eventDate = "Jun 13, 2012 12:00:00 AM";
            eventLocation =             {
                latitude = "43.93838383";
                longitude = "-3.46";
            };
            expirationTime = 1339538400000;
            imageData = "raw data";
            imageFormat = JPEG;
            text = hjhj;
        };
        title = accIDENTE;
        type = ELDIARIOMONTANES;
    }
)

Solution 1

Have you looked at Apple's "NSJSONSerialization" class yet? It became available as of iOS 5.0.

You can use it to convert an Objective C object into a JSON data stream that you can ship up to your web service.

If you want to support OS's older than 5.0, there are other possibilities available (take a look at this related question).

Solution 2

If you only need to support iOS5 and higher, you can use Apple's NSJSONSerialization as Michael said. For earlier iOS versions, you will need to use a third party json parsing library (I recommend JSONKit, it's the fastest).

Ultimately what you're going to be doing is creating an NSDictionary with the key/value structure you want your JSON data to have, and using one of these methods to convert it.

Solution 3

Edited the answer:

Please use NSJSONSerialization to create a JSON object. To create JSON object please don't use string. Use something like dictionaryWithObjectsAndKeys: and the convert it into JSON object

NSDictionary *PostParams = [NSDictionary dictionaryWithObjectsAndKeys:
                             [value], [key], nil];

If you are using iOS 6 and Xcode 4.3 then

NSDictionary *PostParams = @{value, key};