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iOS

Posted by Mathieu Delarue
Mathieu Delarue
5,633 Points

Concurrency

Here is my code:

// // ViewController.swift // Stormy // // Created by Mathieu Delarue on 3/24/15. // Copyright (c) 2015 Mordel. All rights reserved. //

import UIKit

class ViewController: UIViewController {

//Replace the string below with your API Key.
private let apiKey = "4de5319c1c8991a1ff2985013795b0b3"

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    let baseURL = NSURL(string: "https://api.forecast.io/forecast/\(apiKey)/")
    let forecastURL = NSURL(string: "37.8267,-122.423", relativeToURL: baseURL)


    let sharedSession = NSURLSession.sharedSession()

// Below is the error
let downloadTask: NSURLSessionDownloadTask = sharedSession.downloadTaskWithURL(forecastURL, completionHandler: { (location: NSURL!, response: NSURLResponse!, error: NSError!) -> Void in

        if (error == nil) {
            let dataObject = NSData(contentsOfURL: location)
            let weatherDictionary: NSDictionary = NSJSONSerialization.JSONObjectWithData(dataObject, options: nil, error: nil) as NSDictionary
            println(weatherDictionary)
        }

    })

    downloadTask.resume()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}

at the let downloadTask there is an error that says that NSURL is not unwrapped. WHY???

1 Answer

Iulian Popescu
Iulian Popescu
1,363 Points
Iulian Popescu
Iulian Popescu
1,363 Points

Apple documentation says that "An NSURL object initialized with URLString and baseURL. If URLString was malformed, returns nil." when the initializer is called, so the type of your forecastURL is NSURL? and the method downloadWithTask takes value of type NSURL. So this is why it have to be wrapped.