auto-submit · Jun 25, 2025 · May 14, 2025 · May 18, 2025 · May 19, 2025 · May 19, 2025
diff --git a/packages/flutter/lib/src/material/input_decorator.dart b/packages/flutter/lib/src/material/input_decorator.dart
@@ -400,26 +400,33 @@ class _HelperErrorState extends State<_HelperError> with SingleTickerProviderSta
 
   Widget _buildError() {
     assert(widget.error != null || widget.errorText != null);
-    return Semantics(
-      container: true,
-      child: FadeTransition(
-        opacity: _controller,
-        child: FractionalTranslation(
-          translation: Tween<Offset>(
-            begin: const Offset(0.0, -0.25),
-            end: Offset.zero,
-          ).evaluate(_controller.view),
-          child:
-              widget.error ??
-              Text(
-                widget.errorText!,
-                style: widget.errorStyle,
-                textAlign: widget.textAlign,
-                overflow: TextOverflow.ellipsis,
-                maxLines: widget.errorMaxLines,
-              ),
-        ),
-      ),
+    final Widget? capturedError = widget.error;
+    final String? capturedErrorText = widget.errorText;
+    return Builder(
+      builder: (BuildContext context) {
+        return Semantics(
+          container: true,
+          liveRegion: !MediaQuery.supportsAnnounceOf(context),
+          child: FadeTransition(
+            opacity: _controller,
+            child: FractionalTranslation(
+              translation: Tween<Offset>(
+                begin: const Offset(0.0, -0.25),
+                end: Offset.zero,
+              ).evaluate(_controller.view),
+              child:
+                  capturedError ??
+                  Text(
+                    capturedErrorText!,
+                    style: widget.errorStyle,
+                    textAlign: widget.textAlign,
+                    overflow: TextOverflow.ellipsis,
+                    maxLines: widget.errorMaxLines,
+                  ),
+            ),
+          ),
+        );
+      },
     );
   }
 
@@ -3898,6 +3905,7 @@ class InputDecoration {
     bool? alignLabelWithHint,
     BoxConstraints? constraints,
     VisualDensity? visualDensity,
+    SemanticsService? semanticsService,
   }) {
     return InputDecoration(
       icon: icon ?? this.icon,

diff --git a/packages/flutter/lib/src/semantics/semantics_service.dart b/packages/flutter/lib/src/semantics/semantics_service.dart
@@ -7,7 +7,6 @@ library;
 
 import 'dart:ui' show TextDirection;
 
-import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart' show SystemChannels;
 
 import 'semantics_event.dart' show AnnounceSemanticsEvent, Assertiveness, TooltipSemanticsEvent;
@@ -34,8 +33,8 @@ abstract final class SemanticsService {
   /// Currently, this is only supported by the web engine and has no effect on
   /// other platforms. The default mode is [Assertiveness.polite].
   ///
-  /// Not all platforms support announcements. Check to see if
-  /// [isAnnounceSupported] before calling this method.
+  /// Not all platforms support announcements. Check to see if it is supported using
+  /// [MediaQuery.supportsAnnounceOf] before calling this method.
   ///
   /// ### Android
   /// Android has [deprecated announcement events][1] due to its disruptive
@@ -66,12 +65,4 @@ abstract final class SemanticsService {
     final TooltipSemanticsEvent event = TooltipSemanticsEvent(message);
     await SystemChannels.accessibility.send(event.toMap());
   }
-
-  /// Checks if announce is supported on the given platform.
-  ///
-  /// On Android the announce method is deprecated, therefore will return false.
-  /// On other platforms, this will return true.
-  static bool isAnnounceSupported() {
-    return defaultTargetPlatform != TargetPlatform.android;
-  }
 }
diff --git a/packages/flutter/lib/src/widgets/form.dart b/packages/flutter/lib/src/widgets/form.dart
@@ -16,6 +16,7 @@ import 'binding.dart';
 import 'focus_manager.dart';
 import 'focus_scope.dart';
 import 'framework.dart';
+import 'media_query.dart';
 import 'navigator.dart';
 import 'pop_scope.dart';
 import 'restoration.dart';
@@ -369,7 +370,7 @@ class FormState extends State<Form> {
       }
     }
 
-    if (errorMessage.isNotEmpty) {
+    if (errorMessage.isNotEmpty && MediaQuery.supportsAnnounceOf(context)) {
       final TextDirection directionality = Directionality.of(context);
       if (defaultTargetPlatform == TargetPlatform.iOS) {
         unawaited(

diff --git a/packages/flutter/lib/src/widgets/media_query.dart b/packages/flutter/lib/src/widgets/media_query.dart
@@ -103,6 +103,9 @@ enum _MediaQueryAspect {
   /// Specifies the aspect corresponding to [MediaQueryData.boldText].
   boldText,
 
+  /// Specifies the aspect corresponding to [MediaQueryData.supportsAnnounce].
+  supportsAnnounce,
+
   /// Specifies the aspect corresponding to [MediaQueryData.navigationMode].
   navigationMode,
 
@@ -210,6 +213,7 @@ class MediaQueryData {
     this.onOffSwitchLabels = false,
     this.disableAnimations = false,
     this.boldText = false,
+    this.supportsAnnounce = false,
     this.navigationMode = NavigationMode.traditional,
     this.gestureSettings = const DeviceGestureSettings(touchSlop: kTouchSlop),
     this.displayFeatures = const <ui.DisplayFeature>[],
@@ -295,6 +299,9 @@ class MediaQueryData {
           platformData?.disableAnimations ??
           view.platformDispatcher.accessibilityFeatures.disableAnimations,
       boldText = platformData?.boldText ?? view.platformDispatcher.accessibilityFeatures.boldText,
+      supportsAnnounce =
+          platformData?.supportsAnnounce ??
+          view.platformDispatcher.accessibilityFeatures.supportsAnnounce,
       highContrast =
           platformData?.highContrast ?? view.platformDispatcher.accessibilityFeatures.highContrast,
       onOffSwitchLabels =
@@ -584,6 +591,21 @@ class MediaQueryData {
   ///    originates.
   final bool boldText;
 
+  /// Whether accessibility announcements (like [SemanticsService.announce])
+  /// are supported on the current platform.
+  ///
+  /// Returns `false` on platforms where announcements are deprecated or
+  /// unsupported by the underlying platform.
+  ///
+  /// Returns `true` on platforms where such announcements are
+  /// generally supported without discouragement. (iOS, web etc)
+  ///
+  /// See also:
+  ///
+  ///  * [dart:ui.PlatformDispatcher.accessibilityFeatures], where the setting
+  ///    originates.
+  final bool supportsAnnounce;
+
   /// Describes the navigation mode requested by the platform.
   ///
   /// Some user interfaces are better navigated using a directional pad (DPAD)
@@ -665,6 +687,7 @@ class MediaQueryData {
     bool? invertColors,
     bool? accessibleNavigation,
     bool? boldText,
+    bool? supportsAnnounce,
     NavigationMode? navigationMode,
     DeviceGestureSettings? gestureSettings,
     List<ui.DisplayFeature>? displayFeatures,
@@ -690,6 +713,7 @@ class MediaQueryData {
       disableAnimations: disableAnimations ?? this.disableAnimations,
       accessibleNavigation: accessibleNavigation ?? this.accessibleNavigation,
       boldText: boldText ?? this.boldText,
+      supportsAnnounce: supportsAnnounce ?? this.supportsAnnounce,
       navigationMode: navigationMode ?? this.navigationMode,
       gestureSettings: gestureSettings ?? this.gestureSettings,
       displayFeatures: displayFeatures ?? this.displayFeatures,
@@ -892,6 +916,7 @@ class MediaQueryData {
         other.invertColors == invertColors &&
         other.accessibleNavigation == accessibleNavigation &&
         other.boldText == boldText &&
+        other.supportsAnnounce == supportsAnnounce &&
         other.navigationMode == navigationMode &&
         other.gestureSettings == gestureSettings &&
         listEquals(other.displayFeatures, displayFeatures) &&
@@ -1713,6 +1738,30 @@ class MediaQuery extends InheritedModel<_MediaQueryAspect> {
   static bool? maybeBoldTextOf(BuildContext context) =>
       _maybeOf(context, _MediaQueryAspect.boldText)?.boldText;
 
+  /// Returns the [MediaQueryData.supportsAnnounce] accessibility setting for the
+  /// nearest [MediaQuery] ancestor or false, if no such ancestor exists.
+  ///
+  /// Use of this method will cause the given [context] to rebuild any time that
+  /// the [MediaQueryData.supportsAnnounce] property of the ancestor [MediaQuery]
+  /// changes. This is especially important for supportsAnnounce because supportsAnnounce has a
+  /// low frequency change rate. The performance difference between rebuilding
+  /// for all media query data changes and only rebuilding for supportsAnnounce is a
+  /// dramatic difference.
+  ///
+  /// {@macro flutter.widgets.media_query.MediaQuery.dontUseOf}
+  static bool supportsAnnounceOf(BuildContext context) => maybeSupportsAnnounceOf(context) ?? false;
+
+  /// Returns the [MediaQueryData.supportsAnnounce] accessibility setting for the
+  /// nearest [MediaQuery] ancestor or null, if no such ancestor exists.
+  ///
+  /// Use of this method will cause the given [context] to rebuild any time that
+  /// the [MediaQueryData.supportsAnnounce] property of the ancestor [MediaQuery]
+  /// changes.
+  ///
+  /// {@macro flutter.widgets.media_query.MediaQuery.dontUseMaybeOf}
+  static bool? maybeSupportsAnnounceOf(BuildContext context) =>
+      _maybeOf(context, _MediaQueryAspect.supportsAnnounce)?.supportsAnnounce;
+
   /// Returns [MediaQueryData.navigationMode] for the nearest [MediaQuery]
   /// ancestor or throws an exception, if no such ancestor exists.
   ///
@@ -1843,6 +1892,8 @@ class MediaQuery extends InheritedModel<_MediaQueryAspect> {
             _MediaQueryAspect.disableAnimations =>
               data.disableAnimations != oldWidget.data.disableAnimations,
             _MediaQueryAspect.boldText => data.boldText != oldWidget.data.boldText,
+            _MediaQueryAspect.supportsAnnounce =>
+              data.supportsAnnounce != oldWidget.data.supportsAnnounce,
             _MediaQueryAspect.navigationMode =>
               data.navigationMode != oldWidget.data.navigationMode,
             _MediaQueryAspect.gestureSettings =>

diff --git a/packages/flutter/test/material/input_decorator_test.dart b/packages/flutter/test/material/input_decorator_test.dart
@@ -14899,4 +14899,41 @@ void main() {
     final RenderBox box = tester.renderObject(find.byType(InputDecorator));
     expect(box, isNot(paints..drrect()));
   });
+
+  testWidgets(
+    'InputDecorator _buildError with errorText correctly updates on BuildContext updates',
+    (WidgetTester tester) async {
+      final ValueNotifier<String?> errorTextNotifier = ValueNotifier<String?>('initial error');
+      const String helperTextValue = 'helper text';
+
+      addTearDown(errorTextNotifier.dispose);
+
+      await tester.pumpWidget(
+        MaterialApp(
+          home: Scaffold(
+            body: ValueListenableBuilder<String?>(
+              key: const Key('value_listenable_builder_parent'),
+              valueListenable: errorTextNotifier,
+              builder: (BuildContext context, String? value, Widget? child) {
+                return buildInputDecorator(
+                  decoration: InputDecoration(errorText: value, helperText: helperTextValue),
+                );
+              },
+            ),
+          ),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.text('initial error'), findsOneWidget);
+      expect(find.text(helperTextValue), findsNothing);
+
+      errorTextNotifier.value = null;
+
+      await tester.pumpAndSettle();
+
+      expect(find.text('initial error'), findsNothing);
+      expect(find.text(helperTextValue), findsOneWidget);
+    },
+  );
 }
diff --git a/packages/flutter/test/material/text_field_test.dart b/packages/flutter/test/material/text_field_test.dart
@@ -9247,55 +9247,67 @@ void main() {
     semantics.dispose();
   });
 
-  testWidgets('InputDecoration errorText semantics', (WidgetTester tester) async {
-    final SemanticsTester semantics = SemanticsTester(tester);
-    final TextEditingController controller = _textEditingController();
-    final Key key = UniqueKey();
+  for (final bool supportsAnnounce in <bool>[true, false]) {
+    testWidgets('InputDecoration errorText semantics (supportsAnnounce=$supportsAnnounce)', (
+      WidgetTester tester,
+    ) async {
+      final SemanticsTester semantics = SemanticsTester(tester);
+      final TextEditingController controller = _textEditingController();
+      final Key key = UniqueKey();
 
-    await tester.pumpWidget(
-      overlay(
-        child: TextField(
-          key: key,
-          controller: controller,
-          decoration: const InputDecoration(
-            labelText: 'label',
-            hintText: 'hint',
-            errorText: 'oh no!',
+      await tester.pumpWidget(
+        overlay(
+          child: MediaQuery(
+            data: MediaQueryData(supportsAnnounce: supportsAnnounce),
+            child: TextField(
+              key: key,
+              controller: controller,
+              decoration: const InputDecoration(
+                labelText: 'label',
+                hintText: 'hint',
+                errorText: 'oh no!',
+              ),
+            ),
           ),
         ),
-      ),
-    );
+      );
 
-    expect(
-      semantics,
-      hasSemantics(
-        TestSemantics.root(
-          children: <TestSemantics>[
-            TestSemantics.rootChild(
-              label: 'label',
-              textDirection: TextDirection.ltr,
-              actions: <SemanticsAction>[SemanticsAction.tap, SemanticsAction.focus],
-              flags: <SemanticsFlag>[
-                SemanticsFlag.isTextField,
-                SemanticsFlag.hasEnabledState,
-                SemanticsFlag.isEnabled,
-              ],
-              inputType: ui.SemanticsInputType.text,
-              currentValueLength: 0,
-              children: <TestSemantics>[
-                TestSemantics(label: 'oh no!', textDirection: TextDirection.ltr),
-              ],
-            ),
-          ],
+      expect(
+        semantics,
+        hasSemantics(
+          TestSemantics.root(
+            children: <TestSemantics>[
+              TestSemantics.rootChild(
+                label: 'label',
+                textDirection: TextDirection.ltr,
+                actions: <SemanticsAction>[SemanticsAction.tap, SemanticsAction.focus],
+                flags: <SemanticsFlag>[
+                  SemanticsFlag.isTextField,
+                  SemanticsFlag.hasEnabledState,
+                  SemanticsFlag.isEnabled,
+                ],
+                inputType: ui.SemanticsInputType.text,
+                currentValueLength: 0,
+                children: <TestSemantics>[
+                  TestSemantics(
+                    label: 'oh no!',
+                    textDirection: TextDirection.ltr,
+                    flags: <SemanticsFlag>[if (!supportsAnnounce) SemanticsFlag.isLiveRegion],
+                  ),
+                ],
+              ),
+            ],
+          ),
+          ignoreTransform: true,
+          ignoreRect: true,
+          ignoreId: true,
         ),
-        ignoreTransform: true,
-        ignoreRect: true,
-        ignoreId: true,
-      ),
-    );
+      );
 
-    semantics.dispose();
-  });
+      semantics.dispose();
+      debugDefaultTargetPlatformOverride = null;
+    });
+  }
 
   testWidgets('floating label does not overlap with value at large textScaleFactors', (
     WidgetTester tester,