Handle keyboard notification for custom transition. This implementation handles interaction with keyboard frame.

handleKeyboardNotification.swift

extension ViewController {
    @objc func handleKeyboardWillShow(notification: Notification) {
        guard notification.name == UIResponder.keyboardWillShowNotification else {
            return
        }
        guard let keyboardFrame = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else { return }
        let viewFrame = self.view.frame
        let newRect = self.view.convert(self.view.frame, to: self.view.window)
        
        print("KeyboardFrame: \(keyboardFrame)")
        print("ViewFrame: \(viewFrame)")
        print("ConvertedFrame: \(newRect)")
        
        guard newRect.intersects(keyboardFrame) else {
            return
        }
        
        guard let windowHeight = self.view.window?.frame.height else { return }
        
        UIView.animate(withDuration: 0.2) {
            self.navigationController?.view.frame.origin.y = windowHeight - keyboardFrame.height - 4 - self.view.frame.height
        }
        
    }
    
    @objc func handleKeyboardWillHide(notification: Notification) {
        guard notification.name == UIResponder.keyboardWillHideNotification else {
            return
        }
        guard let windowCenter = self.view.window?.center else { return }
        UIView.animate(withDuration: 0.3) {
            self.navigationController?.view.center.y = windowCenter.y
        }
        
    }
}