349 lines
17 KiB
Swift
349 lines
17 KiB
Swift
//
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// AccessibilityHandler.swift
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// MVMCoreUI
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//
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// Created by Bandaru, Krishna Kishore on 30/06/23.
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// Copyright © 2023 Verizon Wireless. All rights reserved.
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//
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import Foundation
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import Combine
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import MVMCore
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import WebKit
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public class AccessbilityOperation: MVMCoreOperation {
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private let argument: Any?
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private let notificationType: UIAccessibility.Notification
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public init(notificationType: UIAccessibility.Notification, argument: Any?) {
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self.notificationType = notificationType
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self.argument = argument
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}
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public override func main() {
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guard UIAccessibility.isVoiceOverRunning, !checkAndHandleForCancellation() else {
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stop()
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return
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}
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Task { @MainActor [weak self] in
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guard let self = self, !self.isCancelled else {
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self?.stop()
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return
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}
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UIAccessibility.post(notification: self.notificationType, argument: self.argument)
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if self.notificationType == .announcement {
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NotificationCenter.default.addObserver(forName: UIAccessibility.announcementDidFinishNotification, object: nil, queue: .main) { _ in
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self.markAsFinished()
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}
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} else {
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self.markAsFinished()
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}
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}
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}
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public func stop() {
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guard isCancelled else { return }
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markAsFinished()
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}
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}
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open class AccessibilityHandler {
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enum RotorType: String, CaseIterable {
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case button = "Buttons"
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case header = "Header"
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var trait: UIAccessibilityTraits {
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switch self {
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case .button:
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return .button
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case .header:
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return .header
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}
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}
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func getUIAccessibilityCustomRotor(itemSearch: @escaping UIAccessibilityCustomRotor.Search) -> UIAccessibilityCustomRotor? {
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var accessibilityCustomRotor: UIAccessibilityCustomRotor?
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switch self {
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case .header:
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accessibilityCustomRotor = UIAccessibilityCustomRotor(systemType: .heading, itemSearch: itemSearch)
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default:
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accessibilityCustomRotor = UIAccessibilityCustomRotor(name: rawValue, itemSearch: itemSearch)
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}
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return accessibilityCustomRotor
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}
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}
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public static func shared() -> Self? {
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guard let shared = CoreUIObject.sharedInstance()?.accessibilityHandler else { return nil }
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return MVMCoreActionUtility.fatalClassCheck(object: shared)
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}
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public var accessibilityId: String?
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public var previousAccessiblityElement: Any?
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public var anyCancellable: Set<AnyCancellable> = []
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public weak var delegate: MVMCoreViewControllerProtocol?
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private var rotorIndexes: [RotorType: Int] = [:]
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private var hasTopNotificationInPage: Bool { NotificationHandler.shared()?.isNotificationShowing() ?? false }
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private let accessibilityOperationQueue: OperationQueue = {
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let queue = OperationQueue()
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queue.maxConcurrentOperationCount = 1
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return queue
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}()
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public init() {
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registerForFocusChanges()
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}
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// MARK: - Accessibility Handler operation events
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open func capturePreviousFocusElement() {
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previousAccessiblityElement = UIAccessibility.focusedElement(using: .notificationVoiceOver)
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}
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open func postAccessbilityToPrevElement() {
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post(notification: .layoutChanged, argument: previousAccessiblityElement)
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previousAccessiblityElement = nil
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}
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public func post(notification type: UIAccessibility.Notification, argument: Any? = nil) {
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guard UIAccessibility.isVoiceOverRunning else { return }
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let accessbilityOperation = AccessbilityOperation(notificationType: type, argument: argument)
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accessibilityOperationQueue.addOperation(accessbilityOperation)
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}
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//To get first focus element on the screen
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open func getFirstFocusedElementOnScreen() -> Any? {
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(delegate as? UIViewController)?.navigationController?.navigationBar
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}
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//Subclass can decide to trigger Accessibility notification on screen change.
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open func canPostAccessbilityNotification(for viewController: UIViewController) -> Bool { true }
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func getPreDefinedFocusedElementIfAny() -> UIView? {
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guard let accessibilityId, let view = (delegate as? UIViewController)?.view else { return nil }
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return MVMCoreUIUtility.findViews(by: MoleculeViewProtocol.self, views: [view]).first {
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$0.model?.id == accessibilityId
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}
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}
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}
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extension AccessibilityHandler {
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public func onPageNew(rootMolecules: [MoleculeModelProtocol], _ delegateObject: MVMCoreUIDelegateObject?) {
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rotorIndexes = [:]
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previousAccessiblityElement = nil
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guard let loadObject = (delegateObject?.loadDelegate as? MVMCoreViewControllerProtocol)?.loadObject else { return }
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accessibilityId = loadObject?.pageJSON?.optionalStringForKey("accessibilityId")
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if let announcementText = loadObject?.pageJSON?.optionalStringForKey("announcementText") {
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post(notification: .announcement, argument: announcementText)
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}
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delegate = delegateObject?.moleculeDelegate as? MVMCoreViewControllerProtocol
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}
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//MARK: - PageVisibiltyBehaviour
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public func willShowPage(_ delegateObject: MVMCoreUIDelegateObject?) {
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updateAccessibilityViews(delegateObject)
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guard let controller = delegateObject?.moleculeDelegate as? UIViewController,
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canPostAccessbilityNotification(for: controller),
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accessibilityId == nil else { return }
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if hasTopNotificationInPage {
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previousAccessiblityElement = getFirstFocusedElementOnScreen()
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} else {
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post(notification: .layoutChanged, argument: getFirstFocusedElementOnScreen())
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}
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}
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///We need to shift focus to any element mentioned in server response i.e to retain focus of the element in new page, from where action is triggered.
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///https://oneconfluence.verizon.com/display/MFD/Accessibility+-+Focus+Retain
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public func onPageShown(_ delegateObject: MVMCoreUIDelegateObject?) {
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identifyAndPrepareRotors(delegateObject)
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DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
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(delegateObject?.moleculeDelegate as? UIViewController)?.view.accessibilityElements = nil
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}
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guard let accessibilityElement = getPreDefinedFocusedElementIfAny() else { return }
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accessibilityId = nil
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if hasTopNotificationInPage {
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previousAccessiblityElement = accessibilityElement
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} else {
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post(notification: .layoutChanged, argument: accessibilityElement)
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}
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}
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//MARK: - Accessibility Methods
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private func updateAccessibilityViews(_ delegateObject: MVMCoreUIDelegateObject?) {
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var currentController = delegateObject?.moleculeDelegate as? UIViewController
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var accessibilityElements: [Any?] = [MVMCoreUISplitViewController.main()?.topAlertView, MVMCoreUISplitViewController.main()?.navigationController]
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if let manager = ((delegateObject?.moleculeDelegate as? MVMCoreViewManagerViewControllerProtocol)?.manager as? MVMCoreViewManagerProtocol & UIViewController),
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let managerAccessibilityElements = manager.getAccessibilityElements() {
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accessibilityElements.append(contentsOf: managerAccessibilityElements)
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accessibilityElements.append(contentsOf: manager.view.subviews)
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currentController = manager
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} else {
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accessibilityElements.append(contentsOf: currentController?.view.subviews ?? [])
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}
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accessibilityElements.append(MVMCoreUISplitViewController.main()?.tabBar)
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currentController?.view.accessibilityElements = accessibilityElements.compactMap { $0 }
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}
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//MARK: - Rotor Methods
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private func identifyAndPrepareRotors(_ delegateObject: MVMCoreUIDelegateObject?) {
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var rotorElements: [UIAccessibilityCustomRotor] = []
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let currentViewController = ((delegateObject?.moleculeDelegate as? MVMCoreViewManagerViewControllerProtocol)?.manager as? SubNavManagerController) ?? (delegateObject?.moleculeDelegate as? ViewController)
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for type in RotorType.allCases {
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if let elements = getTraitMappedElements(currentViewController, type: type),
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let rotor = createRotor(elements, for: type) {
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rotorElements.append(rotor)
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}
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}
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currentViewController?.navigationController?.accessibilityCustomRotors = rotorElements
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}
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private func getTraitMappedElements(_ template: ViewController?, type: RotorType) -> [Any]? {
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var accessibilityElements: [Any?] = []
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switch type {
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case .button:
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accessibilityElements.append(contentsOf: template?.navigationItem.leftBarButtonItems ?? [])
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accessibilityElements.append(contentsOf: template?.navigationItem.rightBarButtonItems ?? [])
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case .header:
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accessibilityElements.append(template?.navigationItem.titleView)
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}
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if let tabs = (template as? SubNavManagerController)?.tabs {
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accessibilityElements.append(contentsOf: tabs.subviews.filter {
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$0.accessibilityTraits.contains(type.trait)
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})
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}
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if let rotorElements = getRotorElementsFrom(template: template, type: type) {
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accessibilityElements.append(contentsOf: rotorElements)
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}
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if let tabBarHidden = (template as? TabPageModelProtocol)?.tabBarHidden, !tabBarHidden {
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accessibilityElements.append(contentsOf: (MVMCoreUISplitViewController.main()?.tabBar?.subviews ?? []).filter {
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$0.accessibilityTraits.contains(type.trait)
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})
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}
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return accessibilityElements.compactMap { $0 }
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}
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private func getRotorElementsFrom(template: ViewController?, type: RotorType) -> [Any]? {
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if let currentViewController = template as? MoleculeListTemplate,
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let templateModel = currentViewController.templateModel,
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let tableView = currentViewController.tableView { //List templates
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var rotorElements: [(model: MoleculeModelProtocol, indexPath: IndexPath)] = [] ///Identifying the trait mapped elements models
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var currentIndexPath: IndexPath?
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rotorElements = templateModel.reduceDepthFirstTraverse(options: .parentFirst, depth: 0, initialResult: rotorElements, nextPartialResult: { result, model, depth in
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if let listModel = model as? (ListItemModelProtocol & MoleculeModelProtocol), let indexPath = currentViewController.getIndexPath(for: listModel) {
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currentIndexPath = indexPath
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}
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var result = result
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if (model.accessibilityTraits?.contains(type.trait) ?? false), let currentIndexPath {
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result.append((model, currentIndexPath))
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}
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return result
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})
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let headerViewElements = MVMCoreUIUtility.findViews(by: MoleculeViewProtocol.self, views: [currentViewController.tableView.tableHeaderView].compactMap { $0 }).filter { $0.accessibilityTraits.contains(type.trait) } as [Any]
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let footerViewElements = MVMCoreUIUtility.findViews(by: MoleculeViewProtocol.self, views: [currentViewController.tableView.tableFooterView].compactMap { $0 }).filter { $0.accessibilityTraits.contains(type.trait) } as [Any]
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let otherInteractiveElements = MVMCoreUIUtility.findViews(by: MoleculeViewProtocol.self, views: [currentViewController.view].compactMap { $0 }, excludedViews: [tableView, tableView.tableFooterView, tableView.tableHeaderView].compactMap { $0 }).filter { $0.accessibilityTraits.contains(type.trait) } as [Any]
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return headerViewElements + otherInteractiveElements + (rotorElements as [Any]) + footerViewElements
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} else if let currentViewController = template as? MoleculeStackTemplate { //Stack templates
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return MVMCoreUIUtility.findViews(by: MoleculeViewProtocol.self, views: [currentViewController.view].compactMap { $0 }).filter { $0.accessibilityTraits.contains(type.trait) } as [Any]
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}
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return nil
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}
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private func createRotor(_ elements: [Any], for type: RotorType) -> UIAccessibilityCustomRotor? {
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guard !elements.isEmpty else { return nil }
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return type.getUIAccessibilityCustomRotor { [weak self] predicate in
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guard let self else { return UIAccessibilityCustomRotorItemResult() }
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var rotorIndex = self.rotorIndexes[type] ?? 0
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if predicate.searchDirection == .next {
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rotorIndex += 1
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if rotorIndex > elements.count {
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rotorIndex = 1
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}
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} else {
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rotorIndex -= 1
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if rotorIndex <= 0 {
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rotorIndex = elements.count
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}
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}
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var rotorElement = elements[rotorIndex - 1]
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if let tableView = (self.delegate as? MoleculeListTemplate)?.tableView,
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let element = rotorElement as? (model: MoleculeModelProtocol, indexPath: IndexPath) { //for List templates
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tableView.scrollToRow(at: element.indexPath, at: .middle, animated: false)
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rotorElement = MVMCoreUIUtility.findViews(by: MoleculeViewProtocol.self, views: [tableView.cellForRow(at: element.indexPath)].compactMap { $0 }).filter { $0.accessibilityTraits.contains(type.trait) && $0.model?.id == element.model.id }.first as Any
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}
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self.rotorIndexes[type] = rotorIndex
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post(notification: .layoutChanged, argument: rotorElement)
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return UIAccessibilityCustomRotorItemResult(targetElement: rotorElement as! NSObjectProtocol, targetRange: nil)
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}
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}
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}
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@objc extension AccessibilityHandler {
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// MARK: - Register with Accessibility Handler listeners
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private func registerForFocusChanges() {
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//Since focus shifted to other elements cancelling existing focus shift notifications if any
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NotificationCenter.default.publisher(for: UIAccessibility.elementFocusedNotification)
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.sink { [weak self] _ in
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self?.accessibilityOperationQueue.cancelAllOperations()
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}.store(in: &anyCancellable)
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}
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func registerForTopNotificationsChanges() {
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NotificationHandler.shared()?.onNotificationWillShow
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.sink { [weak self] (_, model) in
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if self?.previousAccessiblityElement == nil {
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self?.capturePreviousFocusElement()
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}
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}.store(in: &anyCancellable)
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NotificationHandler.shared()?.onNotificationShown
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.sink { [weak self] (view, model) in
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self?.post(notification: .layoutChanged, argument: view)
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}.store(in: &anyCancellable)
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NotificationHandler.shared()?.onNotificationWillDismiss
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.sink { [weak self] (view, model) in
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self?.post(notification: .announcement, argument: MVMCoreUIUtility.hardcodedString(withKey: "AccTopAlertClosed"), priority: .veryHigh)
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}.store(in: &anyCancellable)
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NotificationHandler.shared()?.onNotificationDismissed
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.sink { [weak self] (view, model) in
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self?.postAccessbilityToPrevElement()
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}.store(in: &anyCancellable)
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}
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}
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// MARK: - Accessibility Handler Behaviour
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///Accessibility Handler Behaviour to detect page shown and post notification to first interactive element on screen or the pre-defined focused element.
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open class AccessibilityHandlerBehavior: PageVisibilityBehavior, PageMoleculeTransformationBehavior {
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public let accessibilityHandler: AccessibilityHandler?
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public init(accessibilityHandler: AccessibilityHandler?) {
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self.accessibilityHandler = accessibilityHandler
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}
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required public init(model: PageBehaviorModelProtocol, delegateObject: MVMCoreUIDelegateObject?) {
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accessibilityHandler = AccessibilityHandler.shared() //Protocol Mandatory init method.
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}
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//MARK: - PageMoleculeTransformationBehavior
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public func onPageNew(rootMolecules: [MoleculeModelProtocol], _ delegateObject: MVMCoreUIDelegateObject?) {
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accessibilityHandler?.onPageNew(rootMolecules: rootMolecules, delegateObject)
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}
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//MARK: - PageVisibiltyBehaviour
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open func willShowPage(_ delegateObject: MVMCoreUIDelegateObject?) {
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accessibilityHandler?.willShowPage(delegateObject)
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}
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open func onPageShown(_ delegateObject: MVMCoreUIDelegateObject?) {
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accessibilityHandler?.onPageShown(delegateObject)
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}
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}
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