Swift JSON parsing with Dictionary with Array of Dictionaries

Question

I am a beginner in iOS development with Swift language. I have a JSON file contains the data as below.

{
    \"success\": true,
    \"data\": [
                      


        

Answer 1

You can not return for an asynchronous task. You have to use a callback instead.

Add a callback like this one:

completion: (dictionary: NSDictionary) -> Void

to your parser method signature:

func jsonParserForDataUsage(urlForData: String, completion: (dictionary: NSDictionary) -> Void)

and call the completion where the data you want to "return" is available:

func jsonParserForDataUsage(urlForData: String, completion: (dictionary: NSDictionary) -> Void) {
    print("json parser activated")
    let urlPath = urlForData
    guard let endpoint = NSURL(string: urlPath) else {
        return
    }
    let request = NSMutableURLRequest(URL:endpoint)
    NSURLSession.sharedSession().dataTaskWithRequest(request) { (data, response, error) -> Void in
        do {

            guard let dat = data else {
                throw JSONError.NoData
            }
            guard let dictionary = try NSJSONSerialization.JSONObjectWithData(dat, options:.AllowFragments) as? NSDictionary else {
                throw JSONError.ConversionFailed
            }

            completion(dictionary: dictionary)

        } catch let error as JSONError {
            print(error.rawValue)
        } catch let error as NSError {
            print(error.debugDescription)
        }
    }.resume()

}

Now you can use this method with a trailing closure to get the "returned" value:

jsonParserForDataUsage("http...") { (dictionary) in
    print(dictionary)
}