Android Car Automotive Development - Learn the Android Build System

Master the Android Build System for Android Car Automotive Development.

Learn to create and build Stable AIDL, native C/C++ & Java components, apps, and services within the AOSP Automotive Environment from the ground up focusing on the newest versions of Android 14 and 15.

This book has a total of 6 main chapters and many subchapters designed to help you master the AOSP Automotive Build System from the basics to the interesting and complex details.

Includes a step-by-step guide to setting up the AOSP Car Emulator environment for running the provided example code.

Includes example code which is ready to be run in the AOSP Car Emulator.

A Discord link is included so I can directly assist you with any issues you might encounter.

Chapter Overview

1. AIDL interfaces

Understand Stable AIDL, a crucial variant of Android's Interface Definition Language, designed to guarantee backward compatibility for APIs/ABIs. It primarily facilitates reliable communication between independently updated system components or between the system and apps, vital for modular systems like Project Mainline. This stability is achieved through explicit interface versioning and adherence to stricter rules than standard AIDL. By using Stable AIDL, developers ensure long-term API and ABI stability across updates, enabling robust and maintainable interfaces within the complex Android ecosystem.

Learn how to create a Stable AIDL and build it using the Android Build System.

2. Native Components - Low Level

Master foundational native component development within the AOSP build system using essential low-level modules. Employ defaults to efficiently reuse common C/C++ properties and compiler flags across multiple modules, promoting consistency in your build configuration. Use library headers specifically to package and export header files, making them available for other libraries and binaries. For ultimate flexibility, leverage generation rules to define custom build steps using shell commands, perfect for generating source files or headers dynamically during the build process.

Understanding these modules is key to managing dependencies and complexity in Android native code.

3. Native Components - Mid Level

Effectively manage native library creation within the AOSP build system using versatile mid-level C/C++ components. Utilize static libraries that are directly linked into dependent modules at build time. Conversely, generate dynamic shared libraries, which are loaded at runtime, promoting code reuse across different processes. For maximum flexibility, build both static and shared library versions from a single source set, allowing consumers to choose their preferred linking strategy. Mastering these library types is essential for structuring reusable Android native code and managing dependencies efficiently.

4. Native Components - High Level

Compile native executables directly within the AOSP build system using the essential binary module. This module takes your C/C++ source files and produces a runnable executable program, unlike library modules. It seamlessly links against required C/C++ libraries (both static and shared) to incorporate needed functionality. Developers typically use binary modules to create command-line utilities, test programs, or native daemons intended to run on the Android target.

Understanding binary modules is fundamental for building and deploying functional native code applications within the Android Open Source Project.

5. Java Components - Mid Level

Develop modular Java libraries within the AOSP build system using dedicated mid-level components. Employ java static libraries to create Java archives whose compiled bytecode is specifically marked for direct inclusion into the DEX files of dependent modules, such as Android apps. The versatile java library module also compiles Java sources into Java archive files, serving as the standard way to define reusable libraries, often bundled into apps or used for Android platform code. Both facilitate robust Java code reuse and structured dependency management across projects.

Understanding these modules is key to efficiently building sophisticated Java components within the Android ecosystem.

6. Java Components - High Level

Develop high-level Java components, including crucial Android applications and services, within the AOSP build system. Use the primary android app module to compile Java/Kotlin code, process resources, and package everything needed to build a complete Android app. This module type is the standard for creating installable Android system apps or user applications directly from the platform source. Core Android system services, while not having a single dedicated module type, are typically built using android app modules and integrated deeply into the platform's runtime.

Mastering these high-level constructs is essential for building the functional user-facing and background components that define the Android system image.