Update the AccessibilityPlugin::Announce method to account for the view

dev/integration_tests/new_gallery/lib/pages/backdrop.dart

@@ -264,7 +264,8 @@ class _SettingsIcon extends AnimatedWidget {
             child: InkWell(
               onTap: () {
                 toggleSettings();
-                SemanticsService.announce(
+                SemanticsService.sendAnnouncement(
+                  View.of(context).viewId,
                   _settingsSemanticLabel(isSettingsOpenNotifier.value, context),
                   GalleryOptions.of(context).resolvedTextDirection()!,
                 );

engine/src/flutter/shell/platform/windows/accessibility_plugin.cc

@@ -20,6 +20,7 @@ static constexpr char kAccessibilityChannelName[] = "flutter/accessibility";
 static constexpr char kTypeKey[] = "type";
 static constexpr char kDataKey[] = "data";
 static constexpr char kMessageKey[] = "message";
+static constexpr char kViewIdKey[] = "viewId";
 static constexpr char kAnnounceValue[] = "announce";
 
 // Handles messages like:
@@ -61,7 +62,20 @@ void HandleMessage(AccessibilityPlugin* plugin, const EncodableValue& message) {
       return;
     }
 
-    plugin->Announce(*message);
+    const auto& view_itr = data->find(EncodableValue{kViewIdKey});
+    if (view_itr == data->end()) {
+      FML_LOG(ERROR)
+          << "Accessibility message 'viewId' property must be provided.";
+      return;
+    }
+    const auto* view_id = std::get_if<FlutterViewId>(&view_itr->second);
+    if (!view_id) {
+      FML_LOG(ERROR)
+          << "Accessibility message 'viewId' property must be an int64.";
+      return;
+    }
+
+    plugin->Announce(*view_id, *message);
   } else {
     FML_LOG(WARNING) << "Accessibility message type '" << *type
                      << "' is not supported.";
@@ -89,14 +103,13 @@ void AccessibilityPlugin::SetUp(BinaryMessenger* binary_messenger,
       });
 }
 
-void AccessibilityPlugin::Announce(const std::string_view message) {
+void AccessibilityPlugin::Announce(const FlutterViewId view_id,
+                                   const std::string_view message) {
   if (!engine_->semantics_enabled()) {
     return;
   }
 
-  // TODO(loicsharma): Remove implicit view assumption.
-  // https://github.com/flutter/flutter/issues/142845
-  auto view = engine_->view(kImplicitViewId);
+  auto view = engine_->view(view_id);
   if (!view) {
     return;
   }

engine/src/flutter/shell/platform/windows/accessibility_plugin.h

@@ -12,6 +12,7 @@
 
 namespace flutter {
 
+using FlutterViewId = int64_t;
 class FlutterWindowsEngine;
 
 // Handles messages on the flutter/accessibility channel.
@@ -27,7 +28,8 @@ class AccessibilityPlugin {
                     AccessibilityPlugin* plugin);
 
   // Announce a message through the assistive technology.
-  virtual void Announce(const std::string_view message);
+  virtual void Announce(const FlutterViewId view_id,
+                        const std::string_view message);
 
  private:
   // The engine that owns this plugin.

engine/src/flutter/shell/platform/windows/fixtures/main.dart

@@ -60,9 +60,9 @@ Future<void> sendAccessibilityAnnouncement() async {
 
   // Standard message codec magic number identifiers.
   // See: https://github.com/flutter/flutter/blob/ee94fe262b63b0761e8e1f889ae52322fef068d2/packages/flutter/lib/src/services/message_codecs.dart#L262
-  const int valueMap = 13, valueString = 7;
+  const int valueMap = 13, valueString = 7, valueInt64 = 4;
 
-  // Corresponds to: {"type": "announce", "data": {"message": "hello"}}
+  // Corresponds to: {"type": "announce", "data": {"viewId": 0, "message": "hello"}}
   // See: https://github.com/flutter/flutter/blob/b781da9b5822de1461a769c3b245075359f5464d/packages/flutter/lib/src/semantics/semantics_event.dart#L86
   final Uint8List data = Uint8List.fromList([
     // Map with 2 entries
@@ -73,8 +73,12 @@ Future<void> sendAccessibilityAnnouncement() async {
     valueString, 'announce'.length, ...'announce'.codeUnits,
     // Map key: "data"
     valueString, 'data'.length, ...'data'.codeUnits,
-    // Map value: map with 1 entry
-    valueMap, 1,
+    // Map value: map with 2 entries
+    valueMap, 2,
+    // Map key: "viewId"
+    valueString, 'viewId'.length, ...'viewId'.codeUnits,
+    // Map value: 0
+    valueInt64, 0, 0, 0, 0, 0, 0, 0, 0,
     // Map key: "message"
     valueString, 'message'.length, ...'message'.codeUnits,
     // Map value: "hello"

packages/flutter/lib/src/material/calendar_date_picker.dart

@@ -235,7 +235,8 @@ class _CalendarDatePickerState extends State<CalendarDatePicker> {
       _announcedInitialDate = true;
       final bool isToday = widget.calendarDelegate.isSameDay(widget.currentDate, _selectedDate);
       final String semanticLabelSuffix = isToday ? ', ${_localizations.currentDateLabel}' : '';
-      SemanticsService.announce(
+      SemanticsService.sendAnnouncement(
+        View.of(context).viewId,
         '${_localizations.formatFullDate(_selectedDate!)}$semanticLabelSuffix',
         _textDirection,
       );
@@ -264,7 +265,7 @@ class _CalendarDatePickerState extends State<CalendarDatePicker> {
           DatePickerMode.day => widget.calendarDelegate.formatMonthYear(selected, _localizations),
           DatePickerMode.year => widget.calendarDelegate.formatYear(selected.year, _localizations),
         };
-        SemanticsService.announce(message, _textDirection);
+        SemanticsService.sendAnnouncement(View.of(context).viewId, message, _textDirection);
       }
     });
   }
@@ -314,7 +315,8 @@ class _CalendarDatePickerState extends State<CalendarDatePicker> {
         case TargetPlatform.windows:
           final bool isToday = widget.calendarDelegate.isSameDay(widget.currentDate, _selectedDate);
           final String semanticLabelSuffix = isToday ? ', ${_localizations.currentDateLabel}' : '';
-          SemanticsService.announce(
+          SemanticsService.sendAnnouncement(
+            View.of(context).viewId,
             '${_localizations.selectedDateLabel} ${widget.calendarDelegate.formatFullDate(_selectedDate!, _localizations)}$semanticLabelSuffix',
             _textDirection,
           );
@@ -664,7 +666,8 @@ class _MonthPickerState extends State<_MonthPicker> {
           // the same day of the month.
           _focusedDay = _focusableDayForMonth(_currentMonth, _focusedDay!.day);
         }
-        SemanticsService.announce(
+        SemanticsService.sendAnnouncement(
+          View.of(context).viewId,
           widget.calendarDelegate.formatMonthYear(_currentMonth, _localizations),
           _textDirection,
         );

packages/flutter/lib/src/material/expansion_tile.dart

@@ -538,12 +538,12 @@ class _ExpansionTileState extends State<ExpansionTile> {
       // semantic announcements on iOS. https://github.com/flutter/flutter/issues/122101.
       _timer?.cancel();
       _timer = Timer(const Duration(seconds: 1), () {
-        SemanticsService.announce(stateHint, textDirection);
+        SemanticsService.sendAnnouncement(View.of(context).viewId, stateHint, textDirection);
         _timer?.cancel();
         _timer = null;
       });
     } else {
-      SemanticsService.announce(stateHint, textDirection);
+      SemanticsService.sendAnnouncement(View.of(context).viewId, stateHint, textDirection);
     }
     widget.onExpansionChanged?.call(_tileController.isExpanded);
   }

packages/flutter/lib/src/semantics/semantics_event.dart

@@ -93,13 +93,18 @@ abstract class SemanticsEvent {
 /// [1]: https://developer.android.com/reference/android/view/View#announceForAccessibility(java.lang.CharSequence)
 ///
 class AnnounceSemanticsEvent extends SemanticsEvent {
-  /// Constructs an event that triggers an announcement by the platform.
+  /// Constructs an event that triggers an announcement by the platform
+  /// on the implicit view
   const AnnounceSemanticsEvent(
     this.message,
     this.textDirection, {
     this.assertiveness = Assertiveness.polite,
+    this.viewId = 0,
   }) : super('announce');
 
+  /// The id of the view that this announcement is on.
+  final int viewId;
+
   /// The message to announce.
   final String message;
 
@@ -117,6 +122,7 @@ class AnnounceSemanticsEvent extends SemanticsEvent {
   @override
   Map<String, dynamic> getDataMap() {
     return <String, dynamic>{
+      'viewId': viewId,
       'message': message,
       'textDirection': textDirection.index,
       if (assertiveness != Assertiveness.polite) 'assertiveness': assertiveness.index,

packages/flutter/lib/src/semantics/semantics_service.dart

@@ -22,7 +22,10 @@ export 'dart:ui' show TextDirection;
 /// trigger announcements over using this event.
 abstract final class SemanticsService {
   /// Sends a semantic announcement.
+  /// 
+  /// This method is deprecated. Prefer using [sendAnnouncement] instead.
   ///
+  /// {@template flutter.semantics.service.announce}
   /// This should be used for announcement that are not seamlessly announced by
   /// the system as a result of a UI state change.
   ///
@@ -43,7 +46,9 @@ abstract final class SemanticsService {
   /// trigger announcements.
   ///
   /// [1]: https://developer.android.com/reference/android/view/View#announceForAccessibility(java.lang.CharSequence)
+  /// {@endtemplate}
   ///
+  @Deprecated('Use sendAnnouncement instead.')
   static Future<void> announce(
     String message,
     TextDirection textDirection, {
@@ -57,6 +62,26 @@ abstract final class SemanticsService {
     await SystemChannels.accessibility.send(event.toMap());
   }
 
+
+  /// Sends a semantic announcement for a particular view.
+  ///
+  /// {@macro flutter.semantics.service.announce}
+  ///
+  static Future<void> sendAnnouncement(
+    int viewId,
+    String message,
+    TextDirection textDirection, {
+    Assertiveness assertiveness = Assertiveness.polite,
+  }) async {
+    final AnnounceSemanticsEvent event = AnnounceSemanticsEvent(
+      message,
+      textDirection,
+      assertiveness: assertiveness,
+      viewId: viewId
+    );
+    await SystemChannels.accessibility.send(event.toMap());
+  }
+
   /// Sends a semantic announcement of a tooltip.
   ///
   /// Currently only honored on Android. The contents of [message] will be

packages/flutter/lib/src/widgets/form.dart

@@ -22,6 +22,7 @@ import 'pop_scope.dart';
 import 'restoration.dart';
 import 'restoration_properties.dart';
 import 'routes.dart';
+import 'view.dart';
 import 'will_pop_scope.dart';
 
 // Duration for delay before announcement in IOS so that the announcement won't be interrupted.
@@ -271,10 +272,10 @@ class FormState extends State<Form> {
   Widget build(BuildContext context) {
     switch (widget.autovalidateMode) {
       case AutovalidateMode.always:
-        _validate();
+        _validate(View.of(context).viewId);
       case AutovalidateMode.onUserInteraction:
         if (_hasInteractedByUser) {
-          _validate();
+          _validate(View.of(context).viewId);
         }
       case AutovalidateMode.onUnfocus:
       case AutovalidateMode.disabled:
@@ -335,7 +336,7 @@ class FormState extends State<Form> {
   bool validate() {
     _hasInteractedByUser = true;
     _forceRebuild();
-    return _validate();
+    return _validate(View.of(context).viewId);
   }
 
   /// Validates every [FormField] that is a descendant of this [Form], and
@@ -352,11 +353,11 @@ class FormState extends State<Form> {
     final Set<FormFieldState<Object?>> invalidFields = <FormFieldState<Object?>>{};
     _hasInteractedByUser = true;
     _forceRebuild();
-    _validate(invalidFields);
+    _validate(View.of(context).viewId, invalidFields);
     return invalidFields;
   }
 
-  bool _validate([Set<FormFieldState<Object?>>? invalidFields]) {
+  bool _validate(int viewId, [Set<FormFieldState<Object?>>? invalidFields]) {
     bool hasError = false;
     String errorMessage = '';
     final bool validateOnFocusChange = widget.autovalidateMode == AutovalidateMode.onUnfocus;
@@ -383,15 +384,17 @@ class FormState extends State<Form> {
         unawaited(
           Future<void>(() async {
             await Future<void>.delayed(_kIOSAnnouncementDelayDuration);
-            SemanticsService.announce(
+            SemanticsService.sendAnnouncement(
+              viewId,
               errorMessage,
               directionality,
               assertiveness: Assertiveness.assertive,
             );
           }),
         );
       } else {
-        SemanticsService.announce(
+        SemanticsService.sendAnnouncement(
+          viewId,
           errorMessage,
           directionality,
           assertiveness: Assertiveness.assertive,

packages/flutter/test/semantics/semantics_service_test.dart

@@ -20,8 +20,9 @@ void main() {
     TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
         .setMockDecodedMessageHandler<dynamic>(SystemChannels.accessibility, handleMessage);
 
-    await SemanticsService.announce('announcement 1', TextDirection.ltr);
-    await SemanticsService.announce(
+    await SemanticsService.sendAnnouncement(1, 'announcement 1', TextDirection.ltr);
+    await SemanticsService.sendAnnouncement(
+      2,
       'announcement 2',
       TextDirection.rtl,
       assertiveness: Assertiveness.assertive,
@@ -31,11 +32,12 @@ void main() {
       equals(<Map<String, dynamic>>[
         <String, dynamic>{
           'type': 'announce',
-          'data': <String, dynamic>{'message': 'announcement 1', 'textDirection': 1},
+          'data': <String, dynamic>{'viewId': 1, 'message': 'announcement 1', 'textDirection': 1},
         },
         <String, dynamic>{
           'type': 'announce',
           'data': <String, dynamic>{
+            'viewId': 2,
             'message': 'announcement 2',
             'textDirection': 0,
             'assertiveness': 1,

packages/flutter_test/test/widget_tester_test.dart

@@ -701,26 +701,30 @@ void main() {
         isFalse,
       );
 
-      await SemanticsService.announce('announcement 1', TextDirection.ltr);
-      await SemanticsService.announce(
+      await SemanticsService.sendAnnouncement(0, 'announcement 1', TextDirection.ltr);
+      await SemanticsService.sendAnnouncement(
+        0,
         'announcement 2',
         TextDirection.rtl,
         assertiveness: Assertiveness.assertive,
       );
-      await SemanticsService.announce('announcement 3', TextDirection.rtl);
+      await SemanticsService.sendAnnouncement(0, 'announcement 3', TextDirection.rtl);
 
       final List<CapturedAccessibilityAnnouncement> list = tester.takeAnnouncements();
       expect(list, hasLength(3));
       final CapturedAccessibilityAnnouncement first = list[0];
+      expect(first.viewId, 0);
       expect(first.message, 'announcement 1');
       expect(first.textDirection, TextDirection.ltr);
 
       final CapturedAccessibilityAnnouncement second = list[1];
+      expect(second.viewId, 0);
       expect(second.message, 'announcement 2');
       expect(second.textDirection, TextDirection.rtl);
       expect(second.assertiveness, Assertiveness.assertive);
 
       final CapturedAccessibilityAnnouncement third = list[2];
+      expect(third.viewId, 0);
       expect(third.message, 'announcement 3');
       expect(third.textDirection, TextDirection.rtl);
       expect(third.assertiveness, Assertiveness.polite);
@@ -740,7 +744,8 @@ void main() {
       TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
           .setMockDecodedMessageHandler<dynamic>(SystemChannels.accessibility, handleMessage);
 
-      await SemanticsService.announce(
+      await SemanticsService.sendAnnouncement(
+        0,
         'announcement 1',
         TextDirection.rtl,
         assertiveness: Assertiveness.assertive,
@@ -751,6 +756,7 @@ void main() {
           <String, dynamic>{
             'type': 'announce',
             'data': <String, dynamic>{
+              'viewId': 0,
               'message': 'announcement 1',
               'textDirection': 0,
               'assertiveness': 1,