Swfit 2 “Extra argument 'error' in call”

问题

I've been having a problem understanding what xcode wants from me when it gives me the "Extra argument 'error' in call" it keeps pointing to

if let feed = NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers, error: nil) as? NSDictionary,

I read somewhere that in swift 2 I should add do { but everytime I add it I just keep breaking more stuff. What's the correct syntax in swift 2?

This is the code:

override func viewDidLoad() {
    super.viewDidLoad()
    let request = NSURLRequest(URL: NSURL(string: feedURL)!)
    NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue()) { response, data, error in
        if let feed = NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers, error: nil) as? NSDictionary,
            title = feed.valueForKeyPath("feed.entry.im:name.label") as? String,
            artist = feed.valueForKeyPath("feed.entry.im:artist.label") as? String,
            imageURLs = feed.valueForKeyPath("feed.entry.im:image") as? [NSDictionary] {
                if let imageURL = imageURLs.last,
                    imageURLString = imageURL.valueForKeyPath("label") as? String {
                        self.loadImageFromURL(NSURL(string:imageURLString)!)
                }
            self.titleLabel.text = title
            self.titleLabel.hidden = false
            self.artistLabel.text = artist
            self.artistLabel.hidden = false

        }
    }
}

回答1:

Here is the new way of error handling in swift 2...

do {
     if let feed = try NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers) as? NSDictionary {
      // Success block...
   }
} catch {
    print(error)
}

回答2:

The way to do this in Swift 2 is

let feed = try NSJSONSerialization.JSONObjectWithData(data!, options: .MutableContainers)

来源：https://stackoverflow.com/questions/33470527/swfit-2-extra-argument-error-in-call

标签

ios

swift

swift2