Document accessibility service APIs and integration guide
epic-screen-reader-support-core-services-task-018 — Write developer documentation covering the public APIs of all five components: AccessibilityTestHarness matcher reference and usage examples, FocusManagementService integration guide with route and dialog patterns, AccessibilityAuditService report schema and how to consume violation data, LiveRegionAnnouncer announcement API with BLoC mixin usage, and SensitiveFieldWarningDialog integration checklist. Include a quick-start section for onboarding the Blindeforbundet pilot blind tester.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 7 - 84 tasks
Can start after Tier 6 completes
Implementation Notes
Structure the documentation as five separate Markdown files (one per component) plus a quick-start guide, stored under docs/accessibility/. Cross-link between files where components interact (e.g. LiveRegionAnnouncer doc links to FocusManagementService doc for the BLoC mixin pattern). The quick-start guide for the Blindeforbundet pilot tester should be written in plain language with minimal technical jargon — this person is testing as a blind user, not as a developer.
Include a troubleshooting section in the quick-start guide covering common VoiceOver gestures needed for the activity registration flow. Reference the baseline accessibility audit report from task-017 in the AccessibilityAuditService section so future developers know where to find the debt backlog.
Testing Requirements
Run flutter analyze on all Dart code snippets embedded in the documentation to verify they are syntactically valid. Perform a peer review pass to confirm all integration guide patterns are consistent with the actual implementations delivered in tasks 002–017. The Blindeforbundet quick-start guide should be reviewed by a team member who is not the author to ensure it is understandable to a non-developer blind tester.
Flutter's build pipeline and SemanticsService.announce() operate asynchronously. Announcements triggered too early (before the semantic tree settles) may be swallowed silently on both platforms, causing acceptance criteria around the 500ms window to fail intermittently in CI and on device, which would block pilot launch.
Mitigation & Contingency
Mitigation: Implement the LiveRegionAnnouncer with a post-frame callback delay and an internal timing guard. Write integration tests using WidgetTester.pump() sequences that verify announcement delivery across multiple frame boundaries. Validate on physical devices at each sprint boundary, not only in CI.
Contingency: If consistent announcement timing cannot be achieved within Flutter's semantic pipeline, switch to a platform channel approach that calls native UIAccessibility.post (iOS) and AccessibilityManager.announce (Android) directly, bypassing Flutter's intermediary.
Flutter does not natively emit a focus-gain event to Dart code when VoiceOver or TalkBack moves focus to a specific widget. If the intercept mechanism for the SensitiveFieldWarningDialog relies on an unsupported or undocumented hook in the semantics tree, it may miss focus events for some field types or in some navigation contexts, leaving sensitive data unprotected.
Mitigation & Contingency
Mitigation: Prototype the focus-intercept mechanism during the first sprint of this epic, before building the dialog UI. Evaluate Flutter's SemanticsBinding.instance callbacks and custom SemanticsActions as intercept points. Document the chosen mechanism with platform compatibility notes.
Contingency: If no reliable focus-intercept is available, implement an alternative where sensitive fields show a static 'Screen reader active — tap to reveal' overlay instead of an OS dialog, which is less seamless but achieves equivalent privacy protection without relying on an unreliable event hook.
The AccessibilityTestHarness depends on internal flutter_test semantic tree APIs that can change between Flutter minor versions. If the project upgrades Flutter during this epic, the harness may break silently, causing CI accessibility tests to pass while actually skipping assertions.
Mitigation & Contingency
Mitigation: Pin the Flutter SDK version in pubspec.yaml for the duration of this epic. Document which flutter_test APIs are used and their stability tier. Add a canary test that explicitly fails if the semantic tree API surface changes.
Contingency: If a forced Flutter upgrade breaks the harness, prioritise patching the harness as a blocking task before any other epic work continues, using the canary test failure as the trigger.