Carplay

CarPlay

Build category-entitled, template-based CarPlay apps for the vehicle display. Scope: Swift 6.3, iOS 26+.

See references/carplay-patterns.md for extended patterns including full navigation sessions, dashboard scenes, and advanced template composition.

Scope boundary: full CarPlay framework apps use category entitlements, CPTemplateApplicationScene, CPTemplateApplicationSceneDelegate, CPInterfaceController, and system CPTemplate navigation. CarPlay-visible WidgetKit widgets and ActivityKit Live Activities are separate system experiences; route their implementation to those domains while keeping CarPlay-specific validation here.

Contents

• Workflow
• Route by Task
• Core Decisions
• Common Mistakes
• Review Checklist
• References

Workflow

1. Confirm the app category is eligible and obtain the exact CarPlay entitlement before building templates.
2. Configure the CarPlay scene role and retain the interface controller supplied by the scene delegate.
3. Build only category-allowed template hierarchies and respect tab, list, image, and interaction limits.
4. Keep navigation, audio, communication, and point-of-interest behavior behind their specific templates and completion handlers.
5. Verify reconnect, day/night appearance, multiple display sizes, driving restrictions, and physical vehicle behavior where required.

Route by Task

• Read core implementation details for entitlements, scenes, templates, navigation, audio, communication, POI, and Simulator testing.
• Read extended CarPlay patterns for dashboard/instrument-cluster scenes, complete navigation flows, and complex tab composition.

Core Decisions

• Do not draw arbitrary custom UI where CarPlay requires templates.
• Never push or present templates that Apple exposes only as shared/system surfaces.
• Use the correct scene delegate callback for the app category and display role.
• Call template completion handlers exactly once and keep handlers responsive.

Common Mistakes

DON'T: Use the wrong scene delegate method

Navigation apps must implement templateApplicationScene(_:didConnect:to:) (with CPWindow). Non-navigation apps use templateApplicationScene(_:didConnect:) (no window). Using the wrong variant produces no CarPlay UI.

DON'T: Draw custom UI in the navigation window

CPWindow is exclusively for map content. All overlays, alerts, and controls must use CarPlay templates.

DON'T: Push or present CPTabBarTemplate

CPTabBarTemplate can only be set as root. Pushing or presenting it fails. Use setRootTemplate(_:animated:completion:).

DON'T: Instantiate CPNowPlayingTemplate

Use CPNowPlayingTemplate.shared. Creating a new instance causes issues.

DON'T: Add handlers to CPMessageListItem

CPMessageListItem is Siri-managed, unlike CPListItem. Do not set message.handler; use the item configuration and userInfo for context.

DON'T: Treat widgets as CarPlay template apps

CarPlay-visible widgets and Live Activities belong to WidgetKit and ActivityKit. Use this skill for category-entitled CarPlay template app scenes and for validating those surfaces in the car context.

DON'T: Ignore vehicle display limits

Check CPSessionConfiguration.limitedUserInterfaces and respect maximumItemCount / maximumSectionCount on list templates.

DON'T: Forget to call the completion handler

CPListItem.handler must call its completion handler in every code path. Failure leaves the list in a loading state.

Review Checklist

• Correct CarPlay entitlement key in Entitlements.plist
• UIApplicationSupportsMultipleScenes set to true
• CPTemplateApplicationSceneSessionRoleApplication scene in Info.plist
• Scene delegate class name matches UISceneDelegateClassName
• Correct delegate method used (with/without CPWindow)
• Root template set in didConnect before returning
• Interface controller and window references cleared on disconnect
• CPTabBarTemplate only used as root, never pushed
• CPNowPlayingTemplate.shared used, not a new instance
• Communication rows use CPMessageListItem without custom handlers
• WidgetKit/ActivityKit surfaces routed outside CarPlay template app code
• maximumItemCount/maximumSectionCount checked before populating lists
• CPListItem.handler calls completion in every path
• Map-only content in CPWindow root view controller (navigation apps)
• App functions while iPhone is locked
• Tested at minimum, standard, and high-resolution simulator sizes
• Audio session deactivated when not actively playing

References

• Extended patterns (dashboard, instrument cluster, full nav flow, tab composition): references/carplay-patterns.md
• CarPlay framework
• CPTemplateApplicationSceneDelegate
• CPInterfaceController
• CPMapTemplate
• CPListTemplate
• CPNowPlayingTemplate
• CPPointOfInterestTemplate
• CPNavigationSession
• Requesting CarPlay Entitlements
• Displaying Content in CarPlay
• Using the CarPlay Simulator
• CarPlay HIG
• Core implementation details -- setup, API wiring, and focused implementation recipes moved out of the entrypoint.