No Method declared with Objective-C Selector for Notification UIKeyboardWillShowNotification and UIKeyboardWillHideNotification

Question

After the recent update of Xcode, this code that used to work no longer works. Most of the Selector(":") has an auto correction with the exception for this code:

override func viewDidLoad() {
    super.viewDidLoad()

    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: nil);
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: nil);
}

which flags an error:

No method declared with Objective C selector 'keyboardWillSHow:'

This image show different attempts which have all failed.

What is the new syntax for this code?

Answer 1

Assign the Selector as below:

NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(YourClassName.keyboardWillShow(_:)), name:UIKeyboardWillShowNotification, object: nil);

And the method to update what you want:

func keyboardWillShow(notification: NSNotification) {

     //Update UI or Do Something

}

Same way you can do for UIKeyboardWillHideNotification.

Answer 2

Swift 3 example:

NotificationCenter.default.addObserver(self, selector: #selector(YourClass.keyboardWillShow(notification:)), name:NSNotification.Name.UIKeyboardWillShow, object: nil);
NotificationCenter.default.addObserver(self, selector: #selector(YourClass.keyboardWillHide(notification:)), name:NSNotification.Name.UIKeyboardWillHide, object: nil);

// MARK: - Actions

@objc private func keyboardWillShow(notification: Notification) {
    print("keyboardWillShow called")
}

@objc private func keyboardWillHide(notification: Notification) {
    print("keyboardWillHide called")
}