ViewController+KeyboardWillResize.swift

import UIKit

class ViewController: UIViewController {
  
  override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillResize(_:)), name: UIResponder.keyboardWillChangeFrameNotification, object: nil)
  }

  override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    NotificationCenter.default.removeObserver(self)
  }
  
  @objc func keyboardWillResize(_ notification: Notification) {
    guard let frame = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else { return }
    let height = frame.intersection(self.view.safeAreaLayoutGuide.layoutFrame).height
    UIView.animate(withDuration: 0.24, animations: {
      self.additionalSafeAreaInsets.bottom = max(height, 0)
    })
  }
}