I am trying to get a keyboard size from userInfo using keyboard extension.
I add
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardDidShowNotification, object: nil) inside my KeyboardViewController.swift but keyboardWillShow never gets called.
First register for keyboard notifications
override func viewWillAppear(animated: Bool) { super.viewWillAppear(animated) let notificationCenter = NSNotificationCenter.defaultCenter() notificationCenter.addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil) notificationCenter.addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil) } override func viewDidDisappear(animated: Bool) { super.viewDidDisappear(animated) let notificationCenter = NSNotificationCenter.defaultCenter() notificationCenter.removeObserver(self, name: UIKeyboardWillShowNotification, object: nil) notificationCenter.removeObserver(self, name: UIKeyboardWillHideNotification, object: nil) } then
func keyboardWillShow(notification: NSNotification) { let userInfo = notification.userInfo! let keyboardHeight = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue().height } and you have your height value as a CGFloat
In viewWillAppear, have you added self.subscribeToKeyboardNotifications() ? Just a guess, is your KeyboardViewController seperate from the ViewController in which the keyboard shows up? If so, have `NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardDidShowNotification, object: nil) in a func in the actual ViewController.
use following code for Swift 3.0
override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) let notificationCenter = NotificationCenter.default notificationCenter.addObserver(self, selector: #selector(SignUpViewController.keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil) notificationCenter.addObserver(self, selector: #selector(SignUpViewController.keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil) } override func viewDidDisappear(_ animated: Bool) { super.viewDidDisappear(animated) let notificationCenter = NotificationCenter.default notificationCenter.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil) notificationCenter.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil) } @objc func keyboardWillShow(notification: NSNotification) { let userInfo = notification.userInfo! let keyboardHeight = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue.height UIView.animate(withDuration: 0.3) { self.constraintBottomBtnNext.constant = keyboardHeight; } self.view.layoutIfNeeded(); print(keyboardHeight); } @objc func keyboardWillHide(notification: NSNotification) { UIView.animate(withDuration: 0.3) { self.constraintBottomBtnNext.constant = 0; } self.view.layoutIfNeeded(); } 
