Fix #173302: Announce selected state for AM/PM buttons on iOS

[JulioJ11]

On iOS, VoiceOver did not announce the selected state for the AM/PM buttons in the TimePicker. This change makes sure the selected semantic property is set based on the current platform, allowing VoiceOver to correctly announce the state.

Fixes #173302

Pre-launch Checklist

• [ x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• [x ] I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• [x ] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement].
• [x ] I signed the [CLA].
• [x ] I listed at least one issue that this PR fixes in the description above.
• [x ] I updated/added relevant documentation (doc comments with ///).
• [x ] I added new tests to check the change I am making, or this PR is [test-exempt].
• [x ] I followed the [breaking change policy] and added [Data Driven Fixes] where supported.
• [x ] All existing and new tests are passing.

[gemini-code-assist]

Code Review

This pull request addresses an accessibility issue on iOS where the selected state of AM/PM buttons in the TimePicker was not announced by VoiceOver. The fix correctly uses the selected semantic property on iOS and checked on other platforms. The implementation is straightforward and effective. A new widget test is added to verify the fix on iOS. My review includes a suggestion to improve the test's robustness by using addTearDown for cleanup, ensuring that platform overrides do not leak into other tests.

[gemini-code-assist]

To ensure that debugDefaultTargetPlatformOverride is always reset to its original value, even if the test fails, it's better to use addTearDown. This prevents side effects that could cause subsequent tests to fail.¹

Using addTearDown is the idiomatic way to handle cleanup in Flutter tests. It's also good practice to restore the original platform value instead of assuming it was null.

  final TargetPlatform? originalPlatform = debugDefaultTargetPlatformOverride;
  debugDefaultTargetPlatformOverride = TargetPlatform.iOS;
  addTearDown(() {
    debugDefaultTargetPlatformOverride = originalPlatform;
  });

  await tester.pumpWidget(
    MaterialApp(
      home: Builder(
        builder: (BuildContext context) {
          return TextButton(
            onPressed: () {
              showTimePicker(
                context: context,
                initialTime: const TimeOfDay(hour: 14, minute: 0),
              );
            },
            child: const Text('Open Picker'),
          );
        },
      ),
    ),
  );

  await tester.tap(find.text('Open Picker'));
  await tester.pumpAndSettle();

  final Finder pmButtonSemantics = find.descendant(
    of: find.widgetWithText(InkWell, 'PM'),
    matching: find.byWidgetPredicate(
      (Widget widget) => widget is Semantics && widget.properties.selected == true,
    ),
  );

  final Finder amButtonSemantics = find.descendant(
    of: find.widgetWithText(InkWell, 'AM'),
    matching: find.byWidgetPredicate(
      (Widget widget) => widget is Semantics && widget.properties.selected == false,
    ),
  );

  expect(pmButtonSemantics, findsOneWidget, reason: 'The selected PM button should have Semantics with selected: true');
  expect(amButtonSemantics, findsOneWidget, reason: 'The unselected AM button should have Semantics with selected: false');

Style Guide References

Footnotes

1. Tests should follow best practices for writing effective tests, which includes proper setup and teardown to avoid side-effects between tests. (link) ↩

[chunhtai]

we should check defaultTargetPlatform instead of from the theme, if for some reason someone wants android feels and look on an iOS, the voice over will still be broken

[chunhtai]

you can do testWidget(variant) to test a certain platform

[flutter-dashboard]

This pull request executed golden file tests, but it has not been updated in a while (20+ days). Test results from Gold expire after as many days, so this pull request will need to be updated with a fresh commit in order to get results from Gold.

For more guidance, visit Writing a golden file test for package:flutter.

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

[dkwingsmt]

Hi @JulioJ11 have you had an opportunity to check out the comments above? (from triage)

[Piinks]

Since we have not heard back in quite a while, I am going to close this PR. I am resolving the merge conflicts and applying the feedback from code review to re-land in another PR as we have users waiting on this fix. Thanks for contributing!

[Piinks]

This should be in the library test files as well, not in the sample code test.