Modern Way of Building Android App From Source in AOSP Environment

This will be my first post here, I will start with the first steps one usually does in AOSP; compile an Android App in AOSP Environment as a system application. This topic is also vast, considering the large number of changes you can do with the same, the documents I share will keep evolving. For the scope of this document, I will not consider a prebuilt apk. Goals Compile an android app from source, in AOSP tree and include it as a part of the OS images, like a system app which lives in the directory like: /system/app/SampleSystemApp Similar paths like a or partitions like , , , can also be done in a similar manner. It very much depends on your requirement which partition you want to use, as long as you pass xTS - if required. /system/priv-app system_ext product odm vendor Environment: OS - AOSP Android 13 - android-13.0.0_r37 Target Product: 64 bit only Emulator - sdk_phone64_x86_64-userdebug Implementation: 1. Add the app source code to aosp tree. Here let us assume we have a sample application by the name of . Most of the apps are mostly set up under Let us assume it looks something like this: SampleSystemApp $(SRC_ROOT_DIR)\packages\apps\ packages apps SampleSystemApp And here we have the regular android application source structure inside it, like we have for a normal app from Android Studio. Make sure the has the attribute defined in tag or else aapt will fail the compilation. AndroidManifest.xml package 2. Create an Android.bp file for the build system ( ). soong References can be taken from any default AOSP app as well. Blueprint based Android.bp files will be familiar to developers who have used Bazel before. Example file for our app. This app is written in Kotlin, with compile and target sdk as 33, and min sdk as 28. It will have dependencies on certain libraries (the ones I used are already part of AOSP tree). If you want to use internal SystemAPIs then you can mention and sign this app with platform certificate by using the entry in Android.bp Android.bp platform_apis: true certificate: "platform" package { // See: http://go/android-license-faq default_applicable_licenses: ["Android-Apache-2.0"], } android_app { name: "SampleSystemApp", srcs: [ "app/src/main/java/**/*.kt", ], resource_dirs: [ "app/src/main/res", ], manifest: "app/src/main/AndroidManifest.xml", sdk_version: "33", min_sdk_version: "28", target_sdk_version: "33", static_libs: [ "com.google.android.material_material", "androidx.core_core", "androidx.preference_preference", "androidx.lifecycle_lifecycle-extensions", "androidx-constraintlayout_constraintlayout" ] } To make it a privileged app add the attribute . system/priv-app privileged: true For different partitions, you can consider different attributes like. (a.) (b.) (c.) (d.) system_ext_specific product_specific device_specific soc_specific More documentation on Soong modules and attributes can be referenced from Android CI - . here 3. Now include this module in the PRODUCT_PACKAGES. After , You can manually test the compilation via . Replace the name with the module name you defined in . Here it will be . lunch make name Android.bp SampleSystemApp To include it in the build you need to add it to . PRODUCT_PACKAGES Since we are building target, we should add it to a file under the directory. Here we will use : emulator (goldfish) .mk device/generic/goldfish emulator64_x86_64/device.mk PRODUCT_ARTIFACT_PATH_REQUIREMENT_ALLOWED_LIST += \ system/app/SampleSystemApp/% PRODUCT_PACKAGES += SampleSystemApp The flag is required for and path from Android 11 (API 30) and higher - . You don't need it if the module you are building is to be a part of , or partitions. PRODUCT_ARTIFACT_PATH_REQUIREMENT_ALLOWED_LIST system system_ext link odm vendor product 4. Verification - on build output and live emulator. A. Verify it gets added to the system image via building the entire emulator image. make -j$(nproc --all) B. Check the following paths: (a) - out/target/product/emulator64_x86_64/system/app/ (b) - out/target/product/emulator64_x86_64/installed-files.json Here you should see the files / paths for your app. C. Clean Boot your emulator with permissive SE Linux, printing verbose logs: emulator -no-snapshot-load -selinux permissive Wait for the emulator to boot to the home app, and check the app in the app drawer launcher screen. Or programmatically via where you will see your app package name. adb shell pm list packages D. Test your app and fix bugs if any.