Snackbar a11y fix #173686

nancyflutter · 2025-08-13T06:11:00Z

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google-cla · 2025-08-13T06:11:04Z

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Code Review

This pull request introduces an accessibility improvement for SnackBars by explicitly announcing their content using SemanticsService.announce. This is achieved by wrapping the showSnackBar logic in a new showAccessibleSnackBar helper method. The changes also include updates to the corresponding tests.

My review identifies a few areas for improvement:

The use of Future.delayed for the semantics announcement could be fragile. I've suggested a more robust alternative.
The test file contains duplicate imports that should be cleaned up.
A useful assertion was removed from a test, and I recommend re-adding it to improve test robustness.

Overall, this is a good step towards better accessibility. Addressing the feedback will make the implementation more solid.

gemini-code-assist · 2025-08-13T06:12:12Z

dev/a11y_assessments/lib/use_cases/snack_bar.dart

+    Future<void>.delayed(const Duration(milliseconds: 100), () {
+      debugPrint('Announcing: $message');
+      SemanticsService.announce(message, TextDirection.ltr);
+    });


The use of Future.delayed with a fixed duration can be fragile. The announcement might occur before the SnackBar is fully visible, especially on slower devices or if animations are disabled. For more robustness, consider using WidgetsBinding.instance.addPostFrameCallback to schedule the announcement after the current frame has been rendered. This ensures the SnackBar is on screen when the announcement is made.

WidgetsBinding.instance.addPostFrameCallback((_) { debugPrint('Announcing: $message'); SemanticsService.announce(message, TextDirection.ltr); });

gemini-code-assist · 2025-08-13T06:12:12Z

dev/a11y_assessments/test/snack_bar_test.dart

+import 'package:a11y_assessments/use_cases/snack_bar.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'test_utils.dart';


This file contains duplicate import statements. Please remove the redundant imports on lines 10-13 to improve code clarity and maintainability.

gemini-code-assist · 2025-08-13T06:12:12Z

dev/a11y_assessments/test/snack_bar_test.dart

+import 'package:flutter_test/flutter_test.dart';
+
+import 'test_utils.dart';
+
 void main() {
  testWidgets('snack bar can run', (WidgetTester tester) async {
    await pumpsUseCase(tester, SnackBarUseCase());
    const String snackBarText = 'Awesome Snackbar!';
    expect(find.text(snackBarText), findsNothing);
    await tester.tap(find.text('Show Snackbar'));


The assertion expect(find.text(snackBarText), findsNothing); was removed from this test. This check is valuable because it verifies that the SnackBar is not visible immediately after the tap event and before tester.pump() is called. Restoring this assertion would make the test more thorough by explicitly checking the state transition.

await tester.tap(find.text('Show Snackbar')); expect(find.text(snackBarText), findsNothing);

chunhtai · 2025-08-13T18:21:43Z

dev/a11y_assessments/lib/use_cases/snack_bar.dart

+    );
+
+    Future<void>.delayed(const Duration(milliseconds: 100), () {
+      debugPrint('Announcing: $message');


let's remove print statement

chunhtai · 2025-08-13T18:22:13Z

dev/a11y_assessments/lib/use_cases/snack_bar.dart

+      ),
+    );
+
+    Future<void>.delayed(const Duration(milliseconds: 100), () {


we should only do this for MediaQueryData.supportsAnnounce is true, you can get this from MediaQuery.of(context).

chunhtai · 2025-08-13T18:26:56Z

dev/a11y_assessments/test/snack_bar_test.dart

    await tester.pumpAndSettle();
+    final Finder findHeadingLevelOnes = find.bySemanticsLabel('SnackBar Demo');


Can you add a expect that the message is announced? See this file for example
https://github.com/flutter/flutter/blob/master/packages/flutter/test/semantics/semantics_service_test.dart

…et tests to verify Snackbar visibility and announcement.

chunhtai · 2025-08-15T16:22:40Z

dev/a11y_assessments/pubspec.yaml

@@ -5,8 +5,6 @@ version: 5.0.0+5
 environment:
  sdk: ^3.8.0-0

-resolution: workspace


why this change?

This line was removed because it was not required for this package to work correctly, and it was causing resolution issues during local development. Let me know if you'd prefer to keep it.

chunhtai · 2025-08-15T16:24:13Z

dev/a11y_assessments/lib/use_cases/snack_bar.dart

@@ -1,8 +1,8 @@
 // Copyright 2014 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.


can we revert this?

chunhtai · 2025-08-15T16:24:22Z

dev/a11y_assessments/test/snack_bar_test.dart

@@ -1,27 +1,78 @@
 // Copyright 2014 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.


chunhtai · 2025-08-15T16:26:24Z

dev/a11y_assessments/test/snack_bar_test.dart

+
+      // Verify the message was announced for accessibility
+      await tester.pumpAndSettle();
+      // Note: In test environment, SemanticsService.announce may not work the same way


In test environment the entire widgets binding are mocked, and we should have api to catch any calls to SystemChannel.accessibility, which is where the announcement is sent to

Thanks for pointing that out! I've updated the test to intercept SystemChannels.accessibility and verify that the correct announcement message is sent. Let me know if you have any suggestions on improving the implementation.

This seems not addressed. Do you forget to push the change?

Hi @chunhtai, thanks for the review! I just pushed the update that intercepts SystemChannels.accessibility and verifies the announcement message in the latest commit. Could you please check if the change is now visible on your end? Let me know if anything else needs to be addressed. Thanks!

chunhtai · 2025-08-18T18:25:58Z

dev/a11y_assessments/lib/use_cases/snack_bar.dart

@@ -29,6 +29,25 @@ class MainWidget extends StatefulWidget {
 class MainWidgetState extends State<MainWidget> {
  String pageTitle = getUseCaseName(SnackBarUseCase());

+  /// Shows a SnackBar with accessibility announcement support.
+  /// This method checks if the device supports announcements and announces


Suggested change

/// This method checks if the device supports announcements and announces

///

/// This method checks if the device supports announcements and announces

a new line after the first paragraph

chunhtai · 2025-08-18T18:33:44Z

dev/a11y_assessments/test/snack_bar_test.dart

+
+      // Verify the message was announced for accessibility
+      await tester.pumpAndSettle();
+      // Note: In test environment, SemanticsService.announce may not work the same way


This seems not addressed. Do you forget to push the change?

dev/a11y_assessments/test/snack_bar_test.dart

chunhtai

LGTM

dev/a11y_assessments/lib/use_cases/snack_bar.dart

loic-sharma · 2025-08-20T17:06:29Z

@nancyflutter Could you sign the CLA?

chunhtai · 2025-08-20T17:07:04Z

also, looks like you forgot to sign the cla

Co-authored-by: Loïc Sharma <737941+loic-sharma@users.noreply.github.com>

nancyflutter added 2 commits August 13, 2025 11:36

Fix: Announce Snackbar message for accessibility compliance

d392e4b

Fix: Announce Snackbar message for accessibility compliance

1d71e51

gemini-code-assist bot reviewed Aug 13, 2025

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nancyflutter mentioned this pull request Aug 13, 2025

[VPAT][A11y] snackbar must announce status when opened #173065

Open

chunhtai self-requested a review August 13, 2025 16:32

chunhtai reviewed Aug 13, 2025

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Fix: Announce Snackbar message for accessibility and Implemented widg…

09a40a3

…et tests to verify Snackbar visibility and announcement.

chunhtai reviewed Aug 15, 2025

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chunhtai self-requested a review August 18, 2025 18:05

chunhtai reviewed Aug 18, 2025

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Fix: Add accessibility announcement when showing a SnackBar.

a5181f0

nancyflutter requested a review from chunhtai August 20, 2025 12:59

chunhtai reviewed Aug 20, 2025

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dev/a11y_assessments/test/snack_bar_test.dart Outdated Show resolved Hide resolved

Update dev/a11y_assessments/test/snack_bar_test.dart

d7e27f0

chunhtai approved these changes Aug 20, 2025

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Merge branch 'master' into snackbar_a11y_fix

5862647

loic-sharma reviewed Aug 20, 2025

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dev/a11y_assessments/lib/use_cases/snack_bar.dart Outdated Show resolved Hide resolved

Update dev/a11y_assessments/lib/use_cases/snack_bar.dart

bb9c8ef

Co-authored-by: Loïc Sharma <737941+loic-sharma@users.noreply.github.com>

nancyflutter requested a review from loic-sharma August 21, 2025 08:20

		await tester.pumpAndSettle();
		final Finder findHeadingLevelOnes = find.bySemanticsLabel('SnackBar Demo');

	/// This method checks if the device supports announcements and announces
	///
	/// This method checks if the device supports announcements and announces

Snackbar a11y fix #173686

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Snackbar a11y fix #173686

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nancyflutter commented Aug 13, 2025 •

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