[WIP] Migration to Navigation3

[dturner]

Not ready for review yet....

[gemini-code-assist]

Summary of Changes

Hello @dturner, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This work-in-progress pull request initiates a significant migration towards a new navigation system, likely "Navigation3", by undertaking a substantial refactoring of the application's core navigation composables. The changes aim to enhance the modularity and testability of the navigation architecture by decoupling UI components from direct state management and introducing more explicit state and callback passing. This foundational work prepares the application for a more robust and flexible navigation experience across various device types.

Highlights

• Navigation System Refactoring: The core navigation components (AppWithNavigationSuiteScaffold, AppWithTopBarNavigation, AppWithSpatialNavigation) have been extensively refactored. They now accept granular state and callback parameters instead of direct AppState and NavController objects, significantly improving modularity, reusability, and testability.
• Dynamic Navigation Visibility: The Screens enum has been updated to use a dynamic shouldShowNavigation lambda. This replaces the less flexible NavigationVisibility sealed interface, allowing for more adaptive control over when navigation elements are displayed based on the NavigationComponentType.
• Dependency Updates: The compose-bom and screenshot library versions have been updated to their latest iterations, ensuring the project benefits from the newest features and bug fixes.
• Enhanced Testing Infrastructure: New @AutoPreview annotations for automotive devices and additional screenshot tests have been introduced for the refactored navigation components, bolstering the visual consistency and reliability of the UI across different platforms.

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Changelog

• AdaptiveJetStream/gradle/libs.versions.toml
  • Updated compose-bom to version 2026.01.01.
  • Updated screenshot to version 0.0.1-alpha13.
• AdaptiveJetStream/jetstream/build.gradle.kts
  • Corrected Gradle Kotlin DSL syntax for screenshotTestImplementation dependency.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/MainActivity.kt
  • Added a TODO comment regarding the use of onActivityBackPressed instead of BackHandler.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/App.kt
  • Refactored AppWithNavigationSuiteScaffold, AppWithTopBarNavigation, and AppWithSpatialNavigation to accept explicit state and callback parameters.
  • Introduced logic for hasXrSpatialFeature, global navigation screens, and top bar padding within the NavigationSuiteScaffold block.
  • Added a TODO comment about refactoring keyboard shortcuts.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/app/AppState.kt
  • Restricted direct modification of isTopBarFocused and isNavigationVisible by making their setters private.
  • Updated navigation visibility logic to use a dynamic shouldShowNavigation function from the Screens enum.
  • Changed error handling for unknown screens in updateSelectedScreen.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/app/withNavigationSuiteScaffold/AppWithNavigationSuiteScaffold.kt
  • Refactored the composable to be more generic, accepting state and callbacks as parameters instead of AppState and NavController.
  • Removed internal state management for navigation items and XR features, delegating it to the parent App composable.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/app/withNavigationSuiteScaffold/TopAppBar.kt
  • Added a TODO comment to consider refactoring the TopAppBar to accept a list of navigation items.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/app/withNavigationSuiteScaffold/TopBar.kt
  • Refactored the composable to accept explicit state and callback parameters, aligning with the new modular design.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/app/withNavigationSuiteScaffold/navigationSuiteItems.kt
  • Simplified RequestFullSpaceModeItem by removing the hasXrSpatialFeature check, making its display conditional on the parent.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/app/withSpatialNavigation/AppWithSpatialNavigation.kt
  • Refactored the composable to accept explicit state and callback parameters, removing internal state management for containerColor and navigation destination listeners.
  • Added a TODO comment about repeated code for global navigation screens.
  • Included a preview composable for AppWithSpatialNavigation.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/app/withTopBarNavigation/AppWithTopBarNavigation.kt
  • Refactored the composable to accept explicit state and callback parameters, simplifying its internal logic.
  • Added TODO comments to clarify complex back button handling.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/app/withTopBarNavigation/TopBar.kt
  • Added a TODO comment about a potential bug with top navigation item clicks on TV emulators.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/components/JetStreamPreview.kt
  • Introduced @AutoPreview annotation for automotive device previews.
  • Updated LargeScreensPreview to include @AutoPreview.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/screens/Screens.kt
  • Replaced the NavigationVisibility sealed interface with a dynamic shouldShowNavigation lambda in the Screens enum.
  • Updated MovieDetails and VideoPlayer screen definitions to use the new dynamic navigation visibility logic.
  • Added Javadoc comments for the Screens enum.
• AdaptiveJetStream/jetstream/src/main/java/com/google/jetstream/presentation/theme/Theme.kt
  • Added a TODO comment to consider refactoring the CompositionLocalProvider block.
• AdaptiveJetStream/jetstream/src/screenshotTest/kotlin/com/google/jetstream/presentation/components/ComponentScreenshotTests.kt
  • Added new screenshot test previews for TopBar, TopAppBar, and RequestFullSpaceModeItem.
• AdaptiveJetStream/jetstream/src/screenshotTest/kotlin/com/google/jetstream/presentation/screens/ScreenScreenshotTests.kt
  • Added new screenshot test previews for AppWithNavigationSuiteScaffold and AppWithTopBarNavigation.

Activity

• The pull request is currently marked as 'Work In Progress' (WIP) by the author, dturner.
• The description indicates that the changes are 'Not ready for review yet....', suggesting active development is ongoing.
• No formal review comments or approvals have been recorded at this stage.

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Code Review

This pull request represents a significant and positive refactoring of the application's navigation architecture. The move towards more stateless, composable UI components by lifting state is a great improvement for maintainability and testability. The overall direction is excellent. I've added a few specific comments regarding a potential bug with a missing modifier, a compilation error in a preview, a code style issue, and a suggestion to further improve decoupling of screen-specific logic. Keep up the great work on this refactoring.