class MyViewController: UIViewController {
// This constraint ties an element at zero points from the bottom layout guide
@IBOutlet var keyboardHeightLayoutConstraint: NSLayoutConstraint?
override func viewDidLoad() {
super.viewDidLoad()
// Note that SO highlighting makes the new selector Syntax (#selector()) look
// like a comment but it isn't one
NotificationCenter.default.addobserver(self,selector: #selector(self.keyboardNotification(notification:)),name: NSNotification.Name.UIKeyboardWillChangeFrame,object: nil)
}
deinit {
NotificationCenter.default.removeObserver(self)
}
@objc func keyboardNotification(notification: NSNotification) {
if let userInfo = notification.userInfo {
let endFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
let duration:TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIViewAnimationoptions.curveEaseInOut.rawValue
let animationCurve:UIViewAnimationoptions = UIViewAnimationoptions(rawValue: animationCurveRaw)
if (endFrame?.origin.y)! >= UIScreen.main.bounds.size.height {
self.keyboardHeightLayoutConstraint?.constant = 0.0
} else {
self.keyboardHeightLayoutConstraint?.constant = endFrame?.size.height ?? 0.0
}
UIView.animate(withDuration: duration,delay: TimeInterval(0),options: animationCurve,animations: { self.view.layoutIfNeeded() },completion: nil)
}
}