Drew Olbrich
74 lines
2.8 KiB
Swift
74 lines
2.8 KiB
Swift
//
|
|
// KeyboardNotificationManager.swift
|
|
// ScrollingContentViewController
|
|
//
|
|
// Created by Drew Olbrich on 1/19/19.
|
|
// Copyright 2019 Oath Inc.
|
|
//
|
|
// Licensed under the terms of the MIT License. See the file LICENSE for the full terms.
|
|
//
|
|
|
|
import UIKit
|
|
|
|
/// A singleton that responds to `keyboardWillShow` and `keyboardWillHide`
|
|
/// notification events and forwards them to observers.
|
|
///
|
|
/// Through its `lastNotification` property, this class also exposes the last
|
|
/// received keyboard event, so that view controllers pushed by a navigation
|
|
/// controller can query the current frame of the keyboard, which would be
|
|
/// otherwise inaccessible to them, since it was determined before they were
|
|
/// created.
|
|
internal class KeyboardNotificationManager: NSObject {
|
|
|
|
static let shared = KeyboardNotificationManager()
|
|
|
|
private override init() {
|
|
super.init()
|
|
|
|
let notificationCenter = NotificationCenter.default
|
|
notificationCenter.addObserver(self, selector: #selector(notifyObservers(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
|
|
notificationCenter.addObserver(self, selector: #selector(notifyObservers(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
|
|
}
|
|
|
|
deinit {
|
|
let notificationCenter = NotificationCenter.default
|
|
notificationCenter.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
|
|
notificationCenter.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
|
|
}
|
|
|
|
private struct Observer {
|
|
weak var observing: KeyboardNotificationObserving?
|
|
}
|
|
|
|
private var observers: [Observer] = []
|
|
|
|
/// The last received keyboard notification.
|
|
private(set) var lastNotification: Notification?
|
|
|
|
/// Adds a keyboard notification observer.
|
|
///
|
|
/// - Parameter observing: The observer to notify when a keyboard notification is
|
|
/// received.
|
|
func addKeyboardNotificationObserver(_ observing: KeyboardNotificationObserving) {
|
|
observers.append(Observer(observing: observing))
|
|
}
|
|
|
|
/// Removes a keyboard notification observer.
|
|
///
|
|
/// - Parameter observing: The observer to remove from the list of observers to
|
|
/// notify when a keyboard notification is received.
|
|
func removeKeyboardNotificationObserver(_ observing: KeyboardNotificationObserving) {
|
|
observers.removeAll { $0.observing === observing }
|
|
}
|
|
|
|
/// Notifies all observers about a keyboard notification.
|
|
///
|
|
/// - Parameter notification: The notification to pass to the observers.
|
|
@objc private func notifyObservers(notification: Notification) {
|
|
lastNotification = notification
|
|
|
|
observers.forEach { $0.observing?.didReceiveKeyboardNotification(notification) }
|
|
}
|
|
|
|
}
|