Accessibility updates

Display/ActionSheetController.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-open class ActionSheetController: ViewController {
+open class ActionSheetController: ViewController, PresentableController {
     private var actionSheetNode: ActionSheetControllerNode {
         return self.displayNode as! ActionSheetControllerNode
     }
@@ -23,6 +23,8 @@ open class ActionSheetController: ViewController {
         self.theme = theme
         
         super.init(navigationBarPresentationData: nil)
+        
+        self.blocksBackgroundWhenInOverlay = true
     }
     
     required public init(coder aDecoder: NSCoder) {
@@ -54,10 +56,14 @@ open class ActionSheetController: ViewController {
         self.actionSheetNode.containerLayoutUpdated(layout, transition: transition)
     }
     
-    open override func viewWillAppear(_ animated: Bool) {
+    open override func viewDidAppear(_ animated: Bool) {
-        super.viewWillAppear(animated)
+        super.viewDidAppear(animated)
         
-        self.actionSheetNode.animateIn()
+        self.viewDidAppear(completion: {})
+    }
+    
+    public func viewDidAppear(completion: @escaping () -> Void) {
+        self.actionSheetNode.animateIn(completion: completion)
     }
     
     public func setItemGroups(_ groups: [ActionSheetItemGroup]) {

Display/ActionSheetControllerNode.swift

@@ -110,7 +110,7 @@ final class ActionSheetControllerNode: ASDisplayNode, UIScrollViewDelegate {
         self.updateScrollDimViews(size: layout.size, insets: insets)
     }
     
-    func animateIn() {
+    func animateIn(completion: @escaping () -> Void) {
         let tempDimView = UIView()
         tempDimView.backgroundColor = self.theme.dimColor
         tempDimView.frame = self.bounds.offsetBy(dx: 0.0, dy: -self.bounds.size.height)
@@ -124,6 +124,7 @@ final class ActionSheetControllerNode: ASDisplayNode, UIScrollViewDelegate {
         
         self.layer.animateBounds(from: self.bounds.offsetBy(dx: 0.0, dy: -self.bounds.size.height), to: self.bounds, duration: 0.5, timingFunction: kCAMediaTimingFunctionSpring, completion: { [weak tempDimView] _ in
             tempDimView?.removeFromSuperview()
+            completion()
         })
     }
     

Display/ContainableController.swift

@@ -2,6 +2,10 @@ import UIKit
 import AsyncDisplayKit
 import SwiftSignalKit
 
+public protocol PresentableController: class {
+    func viewDidAppear(completion: @escaping () -> Void)
+}
+
 public protocol ContainableController: class {
     var view: UIView! { get }
     var displayNode: ASDisplayNode { get }

Display/PresentationContext.swift

@@ -189,7 +189,14 @@ final class PresentationContext {
                         (controller as? UIViewController)?.setIgnoreAppearanceMethodInvocations(false)
                         view.layer.invalidateUpTheTree()
                         controller.viewWillAppear(false)
-                        controller.viewDidAppear(false)
+                        if let controller = controller as? PresentableController {
+                            controller.viewDidAppear(completion: { [weak self] in
+                                self?.notifyAccessibilityScreenChanged()
+                            })
+                        } else {
+                            controller.viewDidAppear(false)
+                            strongSelf.notifyAccessibilityScreenChanged()
+                        }
                     }
                     strongSelf.updateViews()
                 }
@@ -246,7 +253,14 @@ final class PresentationContext {
                 }
                 controller.view.frame = CGRect(origin: CGPoint(), size: layout.size)
                 controller.containerLayoutUpdated(layout, transition: .immediate)
-                controller.viewDidAppear(false)
+                if let controller = controller as? PresentableController {
+                    controller.viewDidAppear(completion: { [weak self] in
+                        self?.notifyAccessibilityScreenChanged()
+                    })
+                } else {
+                    controller.viewDidAppear(false)
+                    self.notifyAccessibilityScreenChanged()
+                }
             }
             self.updateViews()
         }
@@ -261,7 +275,7 @@ final class PresentationContext {
     }
     
     private func updateViews() {
-        self.hasOpaqueOverlay = self.isCurrentlyOpaque
+        self.hasOpaqueOverlay = self.currentlyBlocksBackgroundWhenInOverlay
         var topHasOpaque = false
         for (controller, _) in self.controllers.reversed() {
             if topHasOpaque {
@@ -275,6 +289,10 @@ final class PresentationContext {
         }
     }
     
+    private func notifyAccessibilityScreenChanged() {
+        UIAccessibilityPostNotification(UIAccessibilityScreenChangedNotification, nil)
+    }
+    
     func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
         for (controller, _) in self.controllers.reversed() {
             if controller.isViewLoaded {

Display/ViewController.swift

@@ -321,6 +321,10 @@ open class ViewControllerPresentationArguments {
             layer.setTraceableInfo(CATracingLayerInfo(shouldBeAdjustedToInverseTransform: false, userData: self.displayNode.layer, tracingTag: WindowTracingTags.keyboard, disableChildrenTracingTags: 0))
         }
         self.updateScrollToTopView()
+        if let backgroundColor = self.displayNode.backgroundColor, backgroundColor.alpha.isEqual(to: 1.0) {
+            self.blocksBackgroundWhenInOverlay = true
+            self.isOpaqueWhenInOverlay = true
+        }
     }
     
     public func requestLayout(transition: ContainedViewLayoutTransition) {