avoider.swift

final class KeyboardAvoider : ObservableObject {
    
    private var _rects = [Int: CGRect]() {
        didSet {
            print("Keyboard Avoider rects changed: \(_rects.count)")
        }
    }
    var rects: [Int: CGRect] {
        set {
            guard keyboardRect == .zero else {
                print("Warning: Keyboard Avoider changing rects while keyboard is visible.")
                return
            }
            _rects = newValue
        }
        get {
            _rects
        }
    }
    
    var editingField : Int = -1 {
        didSet {
            updateSlideSize()
        }
    }
    
    // MARK: - Publishers
    var slideSizePublisher = CurrentValueSubject<CGSize, Never>(.zero)
    
    // MARK: - Observable interface
    @Published var slideSize: CGSize = .zero
    @Published var isInitialized: Bool = false
    
    @Published var keyboardRect: CGRect = .zero {
        didSet {
            updateSlideSize()
        }
    }
    //private var isKeyboardHidden: Bool = true
    
    private var keyboardWillShow : Cancellable? = nil
    private var keyboardWillHide : Cancellable? = nil
    
    init() {
        print("Keyboard Avoider init")
        
        self.keyboardWillShow = NotificationCenter.default
        .publisher(for: UIResponder.keyboardWillShowNotification)
        .map { (notification) -> CGRect in
            self.isInitialized = true
            if let rect = notification.userInfo?["UIKeyboardFrameEndUserInfoKey"] as? CGRect {
                return rect
            } else {
                return .zero
            }
        }
        .receive(on: RunLoop.main)
        .assign(to: \.keyboardRect, on: self)
        
        self.keyboardWillHide = NotificationCenter.default
        .publisher(for: UIResponder.keyboardWillHideNotification)
        .map {_ -> CGRect in .zero }
        .receive(on: RunLoop.main)
        .eraseToAnyPublisher()
        .assign(to: \.keyboardRect, on: self)
    }
    
    deinit {
        print("Keyboard Avoider deinit")
        
        self.keyboardWillShow?.cancel()
        self.keyboardWillHide?.cancel()
    }
 }