Convert twitter api example from objective-c to swift

Question

I am new to objective C and swift , and have chosen the swift route . I am trying to convert this objective C example to swift and am failing.

Can someone tell me where I am going wrong?

//obj-c

- (void)didTapButton {
    [[Digits sharedInstance] authenticateWithCompletion:^
    (DGTSession* session, NSError *error) {
    if (session) {
    // Inspect session/error objects
}

//swift

@IBAction func loginTouched(sender: AnyObject) {
    var dg = Digits.sharedInstance()
    dg.authenticateWithCompletion { (session: DGTSession!, error: NSError!) in
      //code
    }
}

I am doing something totally wrong, and would appreciate any help. Here's the error.

2014-10-28 00:29:11.754 testign[49947:1809207] -[testign.ViewController loginTouched]: unrecognized selector sent to instance 0x7fba9a542190
2014-10-28 00:29:11.757 testign[49947:1809207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[testign.ViewController loginTouched]: unrecognized selector sent to instance 0x7fba9a542190'

Answer 1

try this

@IBAction func loginTouched(sender: AnyObject) {
    var dg = Digits.sharedInstance()
    dg.authenticateWithCompletion({ (session: DGTSession!, error: NSError!) -> Void in
        //code
    })
}

Answer 2

import UIKit
import TwitterKit

class ViewController: UIViewController {
    var dg = Digits.sharedInstance()
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    //login to digits.
    @IBAction func loginTouched(sender: AnyObject) {
        dg.authenticateWithCompletion { (session: DGTSession!, error: NSError!) in
            if session != nil {
                println("Logged in with session:" + session.authToken)
            } else {
                println("Session object is nil")
            }

        }
    }
    //logout of digits.
    @IBAction func logoutTouched(sender: AnyObject) {
        dg.logOut()
    }

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