Swift: Subclassing ViewController and with add target? - ios

Question

I am creating an app with swift and I subclassed a view controller in which I add a tap gesture recognizer and an NSNotification that listens for the keyboard appearing. I put the selector for the keyboardWillShow in a function in my base view controller. When I subclassed my view controller, however, and I had the keyboard show, my app terminated with an NSException that said that it could not find the selector. Can anyone explain why this happened and how I can fix it?
Here is the functionality in my base view controller:
override func viewDidLoad() {
super.viewDidLoad()
setNotificationListers()
setTapGestureRecognizer()
}
deinit {
NSNotificationCenter.defaultCenter().removeObserver(self)
}
func setNotificationListers() {
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)
}
func setTapGestureRecognizer() {
let tapped = UITapGestureRecognizer(target: self, action: "closeKeyboard")
tapped.numberOfTapsRequired = 1
self.view.addGestureRecognizer(tapped)
}
func closeKeyboard() {
self.view.endEditing(true)
}
func keyboardWillShow() {
self.view.frame.origin.y += CGFloat(keyboardHeight)
}
func keyboardWillHide() {
self.view.frame.origin.y -= CGFloat(keyboardHeight)
}
I did not override anything in my subclass. What will be inherited and what will not?
Thanks in advance for any help!

Answer 1

Your selector declaration require a parameter, but your function does not require a parameter.
Either remove : from your selector declaration
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow"), name: UIKeyboardWillShowNotification, object: nil)
or change your function
func keyboardWillShow(notification: NSNotification) {
self.view.frame.origin.y += CGFloat(keyboardHeight)
}
and do the same for keyboardWillHide.

Answer 2

Note that the Selector method have a :, that means your method need have a parameter.
So, you should change two your methods to this:
func keyboardWillShow(notification: NSNotification) {
self.view.frame.origin.y += CGFloat(keyboardHeight)
}
func keyboardWillHide(notification: NSNotification) {
self.view.frame.origin.y -= CGFloat(keyboardHeight)
}
Anyway, xCode 7.3 has change the way to implement selector. And you can use this great lib https://github.com/hackiftekhar/IQKeyboardManager to handle the keyboard pushing up. Very simple to use.