[usmanvrtx]

Description

Adds an opt-in TV behavior for TabBar: when focus is inside tab content, the first Back press returns focus to the selected tab instead of leaving the screen. A separate Back press then follows the existing navigation behavior. The option defaults to false, so existing behavior is unchanged.

Related Issue

N/A

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactoring (no functional changes)

What Has Changed

• Added the styles.tabFocusOnBack option to TabBar; it is opt-in and defaults to false.
• When enabled on TV, Back from tab content focuses the selected tab, reveals the tab strip if needed, and consumes the associated key repeats and release.
• Kept the behavior scoped to TabBar content; TabBarOnly and ScrollableTabBar are unchanged.
• Added widget tests for selected-tab focus, key event handling, scrolled-away strips, indexed content, runtime tab changes, hidden tabs, non-TV behavior, and expanded layout.
• Documented the option in the layout widgets guide.

How to Test

From modules/ensemble, run:

flutter test test/widget/tab_bar_back_focus_test.dart

On a TV device or emulator, enable styles.tabFocusOnBack: true on a TabBar. Focus an item inside the selected tab and press Back: focus should return to the selected tab without leaving the screen. Press Back again to confirm normal navigation behavior.

Screenshots / Videos

Not applicable.

Checklist

• I have run flutter analyze and addressed any new warnings
• I have run flutter test and all tests pass
• I have tested my changes on the relevant platform(s)
• I have updated documentation if needed
• My changes do not introduce new warnings or errors