How do I fetch data from URL, using xcode 4.3.1 with NSJSONSerialization Class Reference

Question

I am trying to get my head around the NSJSONSerialization Class Reference. In the lack of a code-example at the developer.apple.com website, I´m lost. There are millions of examples all around the web with other json libaries, but I haven´t been able to get any of them to work with the latest build of xcode. (I´m running: Version 4.3.1 (4E1019) and testing on iPhone 5.0.1)

I want to fetch the data from the json file into my iphone using a button.

Lets say I get my data from the URL: http://companyurl/jsonfile.json (standard JSON-format)

The jsonfile.json looks somthing like this…;

{
  "companylist":   
[
      {
        "company":"Companyname 1",
        "telephone":"1234567890",
        "url":"http:\/\/www.companyname1.com\/",
        "category":"category 1",
        "position":"1",
      },
      {
        "company":"Companyname 2",
        "telephone":"2345678901",
        "url":"http:\/\/www.companyname2.com\/",
        "category":"category 2",
        "position":"2",
      },
      {
        "company":"Companyname 3",
        "telephone":"3456789012",
        "url":"http:\/\/www.companyname3.com\/",
        "category":"category 3",
        "position":"3",
      }
]
}

What do I write in my .h, and my .m file?

Thanks for any help! :)

Answer 1

NSData *data=[NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://your_web_server/your_file...."]];
NSError *error=nil;
id response=[NSJSONSerialization JSONObjectWithData:data options:
                                NSJSONReadingMutableContainers error:&error]; 

NSLog(@"Your JSON Object: %@ Or Error is: %@", response, error);

NOTE: This code works on Xcode 4.2 with iOS 5.01 on simulator and 5.1 on iPad device at the moment

Answer 2

Thanks guys. I figured it out. (...and here is what I did:)

In my .m file I added this code:

    - (IBAction)getDataFromJson:(id)sender {
        NSURL *url = [NSURL URLWithString:@"http://yourwebsite.com/jsonfile.json"];

        NSData *jsonData = [NSData dataWithContentsOfURL:url];


        if(jsonData != nil)
        {
            NSError *error = nil;
            id result = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&error];
            if (error == nil)
                NSLog(@"%@", result);
}
}

In my .h file, I added this code:

@interface ViewController : UIViewController
- (IBAction)getDataFromJson:(id)sender;