Problem

The ExpansionTile widget currently relies on SemanticsService.sendAnnouncement to communicate its expanded state. However, this method is deprecated on Android as of API 36.

Solution

To address this, ExpansionTile will be migrated to use a live region for state change announcements. Although a contributor recently introduced expanded flag support for Android, it is limited to API 36+ and is not backward-compatible.

Upstream Dependencies

• Add blockAccessibilityFocus flag #175551: This pull request makes use of the tristate pattern that will enable blocking the live region node from becoming accessibility focusable, which would otherwise disrupt the user experience while using TalkBack.a

Downstream Dependencies

• [A11y] Announce Expansible expansion status #174169: This pull request is a refactor and requires the migration of ExpansionTile away from semantic announcements to copy over the new and improved logic.