matkuznik

let windowSafeArea: CGFloat = windowsSafeAreaWereAdded ? 0 : viewController.view.safeAreaInsets.bottom - viewController.additionalSafeAreaInsets.bottom
viewController.additionalSafeAreaInsets.bottom += beginKeyboardBounds.origin.y - endKeyboardBounds.origin.y - windowSafeArea
windowsSafeAreaWereAdded = true

matkuznik

let duration = userInfo[UIResponder.keyboardAnimationDurationUserInfoKey]
    .flatMap { $0 as? Double } ?? 0.25
if duration > 0 {
    let curve = userInfo[UIResponder.keyboardAnimationCurveUserInfoKey]
    .flatMap { $0 as? Int }
    .flatMap { UIView.AnimationCurve(rawValue: $0) } ?? .easeInOut
    UIViewPropertyAnimator(duration: duration, curve: curve) {
        viewController.view.layoutIfNeeded()
    }
    .startAnimation()

matkuznik

import Foundation

class KeyboardAppearListener {

    private var showKeyboard: NotificationToken?
    private var hideKeyboard: NotificationToken?

    private weak var viewController: UIViewController?
    private var windowSafeArea: CGFloat = 0
    private var windowsSafeAreaWereAdded = false