Car App Library
A Jetpack library introduced by Google that uses a templated framework and a host-client model to provide compliant interface rendering for driving-optimized applications. It automatically adapts to the input methods, screen sizes, and aspect ratios of different vehicle hardware.
Timeline (last 90 days)
Android Auto categories are Google's feature admission model for the car scenario; each category corresponds to a templated UI, developers cannot freely draw the interface, and the category is declared when submitting in Play Console and checked against the Car App Library declaration in the Manifest.
The Car App Library (CAL) is a Jetpack library that uses a templated framework to provide driving-optimized user interfaces while automatically adapting to the various differences in vehicle hardware (input methods, screen sizes, aspect ratios).
CAL's architecture uses a host-client model: the host app is the system renderer and ultimately controls what is displayed on the screen; developers do not draw pixels directly but instead feed structured data and state to CAL templates, which the host renders in a safe, compliant, distraction-optimized layout.
CAL's class structure is divided into three layers: Car App Service is the entry point for communication between the host and the client and is responsible for creating Sessions; a Service has a one-to-many relationship with Sessions, for example a navigation app can create one Session for the main display and one for the instrument cluster; within a Session, a stack of Screen instances is managed, and each Screen is represented by a template class and has its own lifecycle.
Media apps (audio only) have two build paths: the simpler Media Browser Service provides only metadata, and the car's infotainment interface renders the playback UI in a car-optimized way; or building with CAL gives more control over styling and presentation.
All Facts (5)
Android Auto categories are Google's feature admission model for the car scenario; each category corresponds to a templated UI, developers cannot freely draw the interface, and the category is declared when submitting in Play Console and checked against the Car App Library declaration in the Manifest.
50%UnverifiedThe Car App Library (CAL) is a Jetpack library that uses a templated framework to provide driving-optimized user interfaces while automatically adapting to the various differences in vehicle hardware (input methods, screen sizes, aspect ratios).
50%UnverifiedCAL's architecture uses a host-client model: the host app is the system renderer and ultimately controls what is displayed on the screen; developers do not draw pixels directly but instead feed structured data and state to CAL templates, which the host renders in a safe, compliant, distraction-optimized layout.
50%UnverifiedCAL's class structure is divided into three layers: Car App Service is the entry point for communication between the host and the client and is responsible for creating Sessions; a Service has a one-to-many relationship with Sessions, for example a navigation app can create one Session for the main display and one for the instrument cluster; within a Session, a stack of Screen instances is managed, and each Screen is represented by a template class and has its own lifecycle.
50%UnverifiedMedia apps (audio only) have two build paths: the simpler Media Browser Service provides only metadata, and the car's infotainment interface renders the playback UI in a car-optimized way; or building with CAL gives more control over styling and presentation.
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