Hannah Jin ed19f47bec
Add blockAccessibilityFocus flag (#175551)
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"
ecbb115ae3/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.




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2025-11-03 22:18:33 +00:00
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