Add blockAccessibilityFocus flag #175551

hannah-hyj · 2025-09-17T22:15:05Z

Add a new flag for a11y focusable

Accessibility focus, which is the focus used by screen readers like TalkBack and VoiceOver, is different from input focus.
Our current logic use some existing flags to decide if a node is accessibilty focusable. like "if it's a slider / has a check state / has keyboard focus/..., then it's a11y focusable"

flutter/engine/src/flutter/shell/platform/android/io/flutter/view/AccessibilityBridge.java

Line 98 in ecbb115

private static final int FOCUSABLE_FLAGS =
but we lack the ability to explicitly set a node to be unfocusable in a11y!
This flag can be used to explicitly set some semantics nodes to be unfocusable in a11y mode. if it is false, we fall back to the logic "if it's a slider / has a check state / has keyboard focus/..., then it's a11y focusable"

future use case 1:
user can set live region to be not focusable, so when content changes, it will still announce, but the content can't be focused by swiping.
future use case 2:
when pushing a new route like a dialog, setting the semantics nodes in old pages to be un focusable.

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

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flutter-dashboard · 2025-09-17T22:15:07Z

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Code Review

This pull request introduces a new isA11yFocusable flag to SemanticsFlags to control accessibility focus. The changes span across Dart UI, web UI, and native engine code for Android and the embedder API. My review has identified a critical syntax error in packages/flutter/lib/src/semantics/semantics.dart that needs to be fixed. Additionally, for the feature to work on Android, corresponding changes are required in AccessibilityBridge.java to recognize the new semantics flags, which appear to be missing from this PR.

...tter/shell/platform/android/platform_view_android_delegate/platform_view_android_delegate.cc

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

hannah-hyj · 2025-09-17T22:49:31Z

still a draft

justinmc · 2025-09-23T22:20:15Z

@hannah-hyj FYI it still says "draft" in the title of this PR, if it is indeed no longer a draft.

chunhtai · 2025-09-30T23:06:46Z

engine/src/flutter/lib/ui/semantics/semantics_flags.cc

    int isExpanded,
    int isRequired,
    int isFocused,
+    int isA11yFocusable,


our style guide suggest avoid abbreviation. we should use the full name isAccessibilityFocusable

chunhtai · 2025-10-30T18:30:12Z

engine/src/flutter/lib/ui/semantics.dart

  bool hasRepeatedFlags(SemanticsFlags other) {
+    // isAccessibilityFocusBlocked is not checked in `hasRepeatedFlags` because
+    // two semantics nodes both with `isAccessibilityFocusBlocked` set to true is
+    // still compatible and not conflicting.


In this case, the method name no longer correct. Consider rename to something more descriptive

This should be renamed to hasConflictingFlags, but it will be a breaking change.

we should create a new method and deprecate this one.

i will add a breaking change doc

chunhtai · 2025-10-30T21:27:39Z

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

    if (_flags.hasRepeatedFlags(other._flags)) {
      return false;
    }
+    if (_flags.isAccessibilityFocusBlocked != other._flags.isAccessibilityFocusBlocked) {


if one is BlockSubTree another one is BlockCurrent, I think they can merge to be BlockSubTree

and in this case we would need to implement absorb

added to the absorb

chunhtai

LGTM

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

chunhtai · 2025-10-30T22:41:41Z

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

+  blockNode;
+
+  /// The AccessiblityFocusBlockType when two node get merged.
+  AccessiblityFocusBlockType merge(AccessiblityFocusBlockType other) {


should this be private?

Roll Flutter from 027f2e410241 to e5d5c01850f2 (73 revisions) flutter/flutter@027f2e4...e5d5c01 2025-11-04 [email protected] [web] Upgrade Chrome to 141 (for engine tests) (flutter/flutter#177743) 2025-11-04 [email protected] Replace deprecated withOpacity in `chip_animation_style.0.dart‎` example (flutter/flutter#177834) 2025-11-04 [email protected] Roll Skia from 03612114a36d to c89b6118266b (1 revision) (flutter/flutter#177991) 2025-11-04 [email protected] [web] Delete unused futurize util (flutter/flutter#177861) 2025-11-04 [email protected] Roll Skia from 1a179581af75 to 03612114a36d (1 revision) (flutter/flutter#177984) 2025-11-04 [email protected] Roll Skia from 150f844e83fb to 1a179581af75 (3 revisions) (flutter/flutter#177979) 2025-11-04 [email protected] Roll Dart SDK from 6f1bd8d05b1d to 156bf665dba4 (2 revisions) (flutter/flutter#177976) 2025-11-04 [email protected] Roll Skia from 3990fc40acdf to 150f844e83fb (1 revision) (flutter/flutter#177964) 2025-11-04 [email protected] Roll Skia from 85adfd3b8e75 to 3990fc40acdf (1 revision) (flutter/flutter#177962) 2025-11-04 [email protected] Fix `isHeif` crash (flutter/flutter#177944) 2025-11-04 [email protected] Roll Dart SDK from ac065fcd782e to 6f1bd8d05b1d (1 revision) (flutter/flutter#177955) 2025-11-04 [email protected] Roll Skia from 001516d132f0 to 85adfd3b8e75 (4 revisions) (flutter/flutter#177958) 2025-11-04 [email protected] [ Widget Preview ] Add analytic event that's reported when the previewer is opened (flutter/flutter#177949) 2025-11-04 [email protected] Marks Linux_pixel_7pro dynamic_path_stroke_tessellation_perf__timeline_summary to be unflaky (flutter/flutter#171144) 2025-11-03 [email protected] Roll Skia from da9b8fb01101 to 001516d132f0 (6 revisions) (flutter/flutter#177951) 2025-11-03 [email protected] Add FAQ entry about our attempts to remove Skia image codecs. 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Add a new flag for a11y focusable - Accessibility focus, which is the focus used by screen readers like TalkBack and VoiceOver, is different from input focus. - Our current logic use some existing flags to decide if a node is accessibilty focusable. like "if it's a slider / has a check state / has keyboard focus/..., then it's a11y focusable" https://github.com/flutter/flutter/blob/ecbb115ae3a8cba2977ecab9f52086df860cfb1a/engine/src/flutter/shell/platform/android/io/flutter/view/AccessibilityBridge.java#L98 - but we lack the ability to explicitly set a node to be unfocusable in a11y! - This flag can be used to explicitly set some semantics nodes to be unfocusable in a11y mode. if it is false, we fall back to the logic "if it's a slider / has a check state / has keyboard focus/..., then it's a11y focusable" future use case 1: user can set live region to be not focusable, so when content changes, it will still announce, but the content can't be focused by swiping. future use case 2: when pushing a new route like a dialog, setting the semantics nodes in old pages to be un focusable. ## Pre-launch Checklist - [ ] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [ ] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [ ] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [ ] I signed the [CLA]. - [ ] I listed at least one issue that this PR fixes in the description above. - [ ] I updated/added relevant documentation (doc comments with `///`). - [ ] I added new tests to check the change I am making, or this PR is [test-exempt]. - [ ] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [ ] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.  [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

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Add unfocusable semantic property to force non-focus on widgets #165857

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Remove ExpansionTile usage of Semantic Announcements #177785

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Update semantics_test.dart

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hannah-hyj added 2 commits October 30, 2025 15:28

Update semantics.dart

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rename hasRepeatedFlags to hasConflictingFlags

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hannah-hyj added 5 commits October 30, 2025 15:54

resolve comments

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Merge branch 'master' into add-a11y-focusable-flag

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Merge branch 'master' into add-a11y-focusable-flag

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Add blockAccessibilityFocus flag #175551

Add blockAccessibilityFocus flag #175551

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hannah-hyj commented Sep 17, 2025 •

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