How to write Keyboard notifications in Swift 3

Swift 4.2 Xcode 10 (10L213o)

The main changes compared with Swift 3 are in the UIWindow.keyboardWillShowNotification and UIWindow.keyboardWillHideNotification

let notifier = NotificationCenter.defaultnotifier.addObserver(self,                     selector: #selector(KeyboardLayoutConstraint.keyboardWillShowNotification(_:)),                     name: UIWindow.keyboardWillShowNotification,                     object: nil)notifier.addObserver(self,                     selector: #selector(KeyboardLayoutConstraint.keyboardWillHideNotification(_:)),                     name: UIWindow.keyboardWillHideNotification,                     object: nil)@objcfunc keyboardWillShowNotification(_ notification: NSNotification) {}@objcfunc keyboardWillHideNotification(_ notification: NSNotification) {}

Swift 4

override func viewDidLoad() {    super.viewDidLoad()       NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)}func keyboardWillShow(notification: NSNotification) {     print("keyboardWillShow")}func keyboardWillHide(notification: NSNotification){     print("keyboardWillHide")}deinit {     NotificationCenter.default.removeObserver(self)}

You can also get keyboard info using below code inside these methods.

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange), name: .UIKeyboardWillChangeFrame, object: nil) .      @objc func keyboardWillChange(notification: NSNotification) {     let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double     let curve = notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! UInt     let curFrame = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue     let targetFrame = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue     let deltaY = targetFrame.origin.y - curFrame.origin.y }

I fixed this issue by writing the code like this

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)