ios accessibility: started ignoring route changes when presenting modal view controllers (#18544)

shell/platform/darwin/ios/framework/Source/FlutterViewController.mm

@@ -39,6 +39,7 @@ NSNotificationName const FlutterViewControllerShowHomeIndicator =
 @interface FlutterViewController () <FlutterBinaryMessenger, UIScrollViewDelegate>
 @property(nonatomic, readwrite, getter=isDisplayingFlutterUI) BOOL displayingFlutterUI;
 @property(nonatomic, assign) BOOL isHomeIndicatorHidden;
+@property(nonatomic, assign) BOOL isPresentingViewControllerAnimating;
 @end
 
 // The following conditional compilation defines an API 13 concept on earlier API targets so that
@@ -1240,4 +1241,22 @@ static flutter::PointerData::DeviceKind DeviceKindFromTouchType(UITouch* touch)
   return [_engine.get() valuePublishedByPlugin:pluginKey];
 }
 
+- (void)presentViewController:(UIViewController*)viewControllerToPresent
+                     animated:(BOOL)flag
+                   completion:(void (^)(void))completion {
+  self.isPresentingViewControllerAnimating = YES;
+  [super presentViewController:viewControllerToPresent
+                      animated:flag
+                    completion:^{
+                      self.isPresentingViewControllerAnimating = NO;
+                      if (completion) {
+                        completion();
+                      }
+                    }];
+}
+
+- (BOOL)isPresentingViewController {
+  return self.presentedViewController != nil || self.isPresentingViewControllerAnimating;
+}
+
 @end

shell/platform/darwin/ios/framework/Source/FlutterViewController_Internal.h

@@ -23,6 +23,7 @@ extern NSNotificationName const FlutterViewControllerShowHomeIndicator;
 
 @interface FlutterViewController ()
 
+@property(nonatomic, readonly) BOOL isPresentingViewController;
 - (fml::WeakPtr<FlutterViewController>)getWeakPtr;
 - (flutter::FlutterPlatformViewsController*)platformViewsController;
 

shell/platform/darwin/ios/framework/Source/accessibility_bridge.h

@@ -36,9 +36,21 @@ class PlatformViewIOS;
  */
 class AccessibilityBridge final : public AccessibilityBridgeIos {
  public:
+  /** Delegate for handling iOS operations. */
+  class IosDelegate {
+   public:
+    virtual ~IosDelegate() = default;
+    /// Returns true when the FlutterViewController associated with the `view`
+    /// is presenting a modal view controller.
+    virtual bool IsFlutterViewControllerPresentingModalViewController(UIView* view) = 0;
+    virtual void PostAccessibilityNotification(UIAccessibilityNotifications notification,
+                                               id argument) = 0;
+  };
+
   AccessibilityBridge(UIView* view,
                       PlatformViewIOS* platform_view,
-                      FlutterPlatformViewsController* platform_views_controller);
+                      FlutterPlatformViewsController* platform_views_controller,
+                      std::unique_ptr<IosDelegate> ios_delegate = nullptr);
   ~AccessibilityBridge();
 
   void UpdateSemantics(flutter::SemanticsNodeUpdates nodes,
@@ -75,6 +87,7 @@ class AccessibilityBridge final : public AccessibilityBridgeIos {
   int32_t previous_route_id_;
   std::unordered_map<int32_t, flutter::CustomAccessibilityAction> actions_;
   std::vector<int32_t> previous_routes_;
+  std::unique_ptr<IosDelegate> ios_delegate_;
 
   FML_DISALLOW_COPY_AND_ASSIGN(AccessibilityBridge);
 };

shell/platform/darwin/ios/framework/Source/accessibility_bridge.mm

@@ -4,6 +4,7 @@
 
 #import "flutter/shell/platform/darwin/ios/framework/Source/accessibility_bridge.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterEngine_Internal.h"
+#import "flutter/shell/platform/darwin/ios/framework/Source/FlutterViewController_Internal.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/accessibility_text_entry.h"
 
 #import "flutter/shell/platform/darwin/ios/platform_view_ios.h"
@@ -13,17 +14,54 @@
 FLUTTER_ASSERT_NOT_ARC
 
 namespace flutter {
+namespace {
+
+FlutterViewController* _Nullable GetFlutterViewControllerForView(UIView* view) {
+  // There is no way to get a view's view controller in UIKit directly, this is
+  // somewhat of a hacky solution to get that.  This could be eliminated if the
+  // bridge actually kept a reference to a FlutterViewController instead of a
+  // UIView.
+  id nextResponder = [view nextResponder];
+  if ([nextResponder isKindOfClass:[FlutterViewController class]]) {
+    return nextResponder;
+  } else if ([nextResponder isKindOfClass:[UIView class]]) {
+    return GetFlutterViewControllerForView(nextResponder);
+  } else {
+    return nil;
+  }
+}
+
+class DefaultIosDelegate : public AccessibilityBridge::IosDelegate {
+ public:
+  bool IsFlutterViewControllerPresentingModalViewController(UIView* view) override {
+    FlutterViewController* viewController = GetFlutterViewControllerForView(view);
+    if (viewController) {
+      return viewController.isPresentingViewController;
+    } else {
+      return false;
+    }
+  }
+
+  void PostAccessibilityNotification(UIAccessibilityNotifications notification,
+                                     id argument) override {
+    UIAccessibilityPostNotification(notification, argument);
+  }
+};
+}  // namespace
 
 AccessibilityBridge::AccessibilityBridge(UIView* view,
                                          PlatformViewIOS* platform_view,
-                                         FlutterPlatformViewsController* platform_views_controller)
+                                         FlutterPlatformViewsController* platform_views_controller,
+                                         std::unique_ptr<IosDelegate> ios_delegate)
     : view_(view),
       platform_view_(platform_view),
       platform_views_controller_(platform_views_controller),
       objects_([[NSMutableDictionary alloc] init]),
       weak_factory_(this),
       previous_route_id_(0),
-      previous_routes_({}) {
+      previous_routes_({}),
+      ios_delegate_(ios_delegate ? std::move(ios_delegate)
+                                 : std::make_unique<DefaultIosDelegate>()) {
   accessibility_channel_.reset([[FlutterBasicMessageChannel alloc]
          initWithName:@"flutter/accessibility"
       binaryMessenger:platform_view->GetOwnerViewController().get().engine.binaryMessenger
@@ -137,15 +175,18 @@ void AccessibilityBridge::UpdateSemantics(flutter::SemanticsNodeUpdates nodes,
 
   layoutChanged = layoutChanged || [doomed_uids count] > 0;
   if (routeChanged) {
-    NSString* routeName = [lastAdded routeName];
-    UIAccessibilityPostNotification(UIAccessibilityScreenChangedNotification, routeName);
+    if (!ios_delegate_->IsFlutterViewControllerPresentingModalViewController(view_)) {
+      NSString* routeName = [lastAdded routeName];
+      ios_delegate_->PostAccessibilityNotification(UIAccessibilityScreenChangedNotification,
+                                                   routeName);
+    }
   } else if (layoutChanged) {
     // TODO(goderbauer): figure out which node to focus next.
-    UIAccessibilityPostNotification(UIAccessibilityLayoutChangedNotification, nil);
+    ios_delegate_->PostAccessibilityNotification(UIAccessibilityLayoutChangedNotification, nil);
   }
   if (scrollOccured) {
     // TODO(tvolkert): provide meaningful string (e.g. "page 2 of 5")
-    UIAccessibilityPostNotification(UIAccessibilityPageScrolledNotification, @"");
+    ios_delegate_->PostAccessibilityNotification(UIAccessibilityPageScrolledNotification, @"");
   }
 }
 
@@ -233,7 +274,7 @@ void AccessibilityBridge::HandleEvent(NSDictionary<NSString*, id>* annotatedEven
   NSString* type = annotatedEvent[@"type"];
   if ([type isEqualToString:@"announce"]) {
     NSString* message = annotatedEvent[@"data"][@"message"];
-    UIAccessibilityPostNotification(UIAccessibilityAnnouncementNotification, message);
+    ios_delegate_->PostAccessibilityNotification(UIAccessibilityAnnouncementNotification, message);
   }
 }
 

shell/platform/darwin/ios/framework/Source/accessibility_bridge_test.mm

@@ -86,6 +86,22 @@ class MockDelegate : public PlatformView::Delegate {
   void OnPlatformViewUnregisterTexture(int64_t texture_id) override {}
   void OnPlatformViewMarkTextureFrameAvailable(int64_t texture_id) override {}
 };
+
+class MockIosDelegate : public AccessibilityBridge::IosDelegate {
+ public:
+  bool IsFlutterViewControllerPresentingModalViewController(UIView* view) override {
+    return result_IsFlutterViewControllerPresentingModalViewController_;
+  };
+
+  void PostAccessibilityNotification(UIAccessibilityNotifications notification,
+                                     id argument) override {
+    if (on_PostAccessibilityNotification_) {
+      on_PostAccessibilityNotification_(notification, argument);
+    }
+  }
+  std::function<void(UIAccessibilityNotifications, id)> on_PostAccessibilityNotification_;
+  bool result_IsFlutterViewControllerPresentingModalViewController_ = false;
+};
 }  // namespace
 }  // namespace flutter
 
@@ -238,4 +254,112 @@ fml::RefPtr<fml::TaskRunner> CreateNewThread(std::string name) {
   XCTAssertNil(gMockPlatformView);
 }
 
+- (void)testAnnouncesRouteChanges {
+  flutter::MockDelegate mock_delegate;
+  auto thread_task_runner = CreateNewThread("AccessibilityBridgeTest");
+  flutter::TaskRunners runners(/*label=*/self.name.UTF8String,
+                               /*platform=*/thread_task_runner,
+                               /*raster=*/thread_task_runner,
+                               /*ui=*/thread_task_runner,
+                               /*io=*/thread_task_runner);
+  auto platform_view = std::make_unique<flutter::PlatformViewIOS>(
+      /*delegate=*/mock_delegate,
+      /*rendering_api=*/flutter::IOSRenderingAPI::kSoftware,
+      /*task_runners=*/runners);
+  id mockFlutterView = OCMClassMock([FlutterView class]);
+  std::string label = "some label";
+
+  NSMutableArray<NSDictionary<NSString*, id>*>* accessibility_notifications =
+      [[[NSMutableArray alloc] init] autorelease];
+  auto ios_delegate = std::make_unique<flutter::MockIosDelegate>();
+  ios_delegate->on_PostAccessibilityNotification_ =
+      [accessibility_notifications](UIAccessibilityNotifications notification, id argument) {
+        [accessibility_notifications addObject:@{
+          @"notification" : @(notification),
+          @"argument" : argument ? argument : [NSNull null],
+        }];
+      };
+  __block auto bridge =
+      std::make_unique<flutter::AccessibilityBridge>(/*view=*/mockFlutterView,
+                                                     /*platform_view=*/platform_view.get(),
+                                                     /*platform_views_controller=*/nil,
+                                                     /*ios_delegate=*/std::move(ios_delegate));
+
+  flutter::CustomAccessibilityActionUpdates actions;
+  flutter::SemanticsNodeUpdates nodes;
+
+  flutter::SemanticsNode route_node;
+  route_node.id = 1;
+  route_node.label = label;
+  route_node.flags = static_cast<int32_t>(flutter::SemanticsFlags::kScopesRoute) |
+                     static_cast<int32_t>(flutter::SemanticsFlags::kNamesRoute);
+  route_node.label = "route";
+  nodes[route_node.id] = route_node;
+  flutter::SemanticsNode root_node;
+  root_node.id = kRootNodeId;
+  root_node.label = label;
+  root_node.childrenInTraversalOrder = {1};
+  root_node.childrenInHitTestOrder = {1};
+  nodes[root_node.id] = root_node;
+  bridge->UpdateSemantics(/*nodes=*/nodes, /*actions=*/actions);
+
+  XCTAssertEqual([accessibility_notifications count], 1ul);
+  XCTAssertEqualObjects(accessibility_notifications[0][@"argument"], @"route");
+  XCTAssertEqual([accessibility_notifications[0][@"notification"] unsignedIntValue],
+                 UIAccessibilityScreenChangedNotification);
+}
+
+- (void)testAnnouncesIgnoresRouteChangesWhenModal {
+  flutter::MockDelegate mock_delegate;
+  auto thread_task_runner = CreateNewThread("AccessibilityBridgeTest");
+  flutter::TaskRunners runners(/*label=*/self.name.UTF8String,
+                               /*platform=*/thread_task_runner,
+                               /*raster=*/thread_task_runner,
+                               /*ui=*/thread_task_runner,
+                               /*io=*/thread_task_runner);
+  auto platform_view = std::make_unique<flutter::PlatformViewIOS>(
+      /*delegate=*/mock_delegate,
+      /*rendering_api=*/flutter::IOSRenderingAPI::kSoftware,
+      /*task_runners=*/runners);
+  id mockFlutterView = OCMClassMock([FlutterView class]);
+  std::string label = "some label";
+
+  NSMutableArray<NSDictionary<NSString*, id>*>* accessibility_notifications =
+      [[[NSMutableArray alloc] init] autorelease];
+  auto ios_delegate = std::make_unique<flutter::MockIosDelegate>();
+  ios_delegate->on_PostAccessibilityNotification_ =
+      [accessibility_notifications](UIAccessibilityNotifications notification, id argument) {
+        [accessibility_notifications addObject:@{
+          @"notification" : @(notification),
+          @"argument" : argument ? argument : [NSNull null],
+        }];
+      };
+  ios_delegate->result_IsFlutterViewControllerPresentingModalViewController_ = true;
+  __block auto bridge =
+      std::make_unique<flutter::AccessibilityBridge>(/*view=*/mockFlutterView,
+                                                     /*platform_view=*/platform_view.get(),
+                                                     /*platform_views_controller=*/nil,
+                                                     /*ios_delegate=*/std::move(ios_delegate));
+
+  flutter::CustomAccessibilityActionUpdates actions;
+  flutter::SemanticsNodeUpdates nodes;
+
+  flutter::SemanticsNode route_node;
+  route_node.id = 1;
+  route_node.label = label;
+  route_node.flags = static_cast<int32_t>(flutter::SemanticsFlags::kScopesRoute) |
+                     static_cast<int32_t>(flutter::SemanticsFlags::kNamesRoute);
+  route_node.label = "route";
+  nodes[route_node.id] = route_node;
+  flutter::SemanticsNode root_node;
+  root_node.id = kRootNodeId;
+  root_node.label = label;
+  root_node.childrenInTraversalOrder = {1};
+  root_node.childrenInHitTestOrder = {1};
+  nodes[root_node.id] = root_node;
+  bridge->UpdateSemantics(/*nodes=*/nodes, /*actions=*/actions);
+
+  XCTAssertEqual([accessibility_notifications count], 0ul);
+}
+
 @end