KeyboardResponder.swift

//https://stackoverflow.com/questions/56491881/move-textfield-up-when-the-keyboard-has-appeared-in-swiftui
import SwiftUI

final class KeyboardResponder: ObservableObject {
    private var notificationCenter: NotificationCenter
    @Published private(set) var currentHeight: CGFloat = 0

    init(center: NotificationCenter = .default) {
        notificationCenter = center
        notificationCenter.addObserver(self, selector: #selector(keyBoardWillShow(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
        notificationCenter.addObserver(self, selector: #selector(keyBoardWillHide(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
    }

    deinit {
        notificationCenter.removeObserver(self)
    }

    @objc func keyBoardWillShow(notification: Notification) {
        if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
            currentHeight = keyboardSize.height
        }
    }

    @objc func keyBoardWillHide(notification: Notification) {
        currentHeight = 0
    }
}