无法识别的选择器发送到实例Swift NSNotification

Question

I watched this video on a Messaging App for Swift and copied it word for word. Yet, there have been some updates to Xcode recently so I am not sure if that is the problem or I typed something in wrong. I also looked at other questions similar to mine and still can't find the issue.

The code I putting in the viewDidLoad() deals with the showing the keyboard:

    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWasShown", name: UIKeyboardDidShowNotification, object: nil)

Then I call the keyboardWasShow function here:

 func keyboardWasShown(notification: NSNotification) {

    let dict : NSDictionary = notification.userInfo!
    let s : NSValue = dict.valueForKey(UIKeyboardFrameEndUserInfoKey) as! NSValue
    let rect : CGRect = s.CGRectValue()

    UIView.animateWithDuration(0.3, delay: 0, options: .CurveLinear, animations: {

        self.resultsScrollView.frame.origin.y = self.scrollViewOriginalY - rect.height
        self.frameMessageView.frame.origin.y = self.frameMessageOriginalY - rect.height

        var bottomOffset : CGPoint = CGPointMake(0, self.resultsScrollView.contentSize.height - self.resultsScrollView.bounds.size.height)

        self.resultsScrollView.setContentOffset(bottomOffset, animated: false)

        }, completion: {
            (finished: Bool) in

            //

    })

}

The reason why I think it's the keyboardWasShown function because output showed keyboardWasShown]: unrecognized selector sent to instance 0x7f848c12be40

Any help would be appreciated!

Answer 1

The method you implemented takes an argument so you need to add a colon to the end of the selector name.

 let center = NSNotificationCenter.defaultCenter()
 center.addObserver(self, 
                    selector: "keyboardWasShown:",
                    name: UIKeyboardDidShowNotification,
                    object: nil)