Android Build Systems This skill covers building Android apps via Gradle CLI and building custom ROMs via AOSP/LineageOS. App Building (Gradle CLI) Essential Commands ./gradlew tasks

List available tasks

./gradlew assembleDebug

Build debug APK

./gradlew assembleRelease

Build release APK

./gradlew installDebug

Build + install to device

./gradlew bundleRelease

Build AAB (App Bundle)

APK output location

app/build/outputs/apk/debug/app-debug.apk

app/build/outputs/apk/release/app-release.apk

Build Variants ./gradlew assembleFreeDebug

Flavor + build type

./gradlew assemblePaidRelease ./gradlew assembleDebug --info

Verbose output

./gradlew assembleRelease -x test

Skip tests

Testing ./gradlew test

Unit tests

./gradlew testDebugUnitTest

Debug unit tests only

./gradlew connectedAndroidTest

Instrumented tests

./gradlew connectedCheck

All connected tests

Run specific test

./gradlew test --tests "*.MyTestClass" Linting & Analysis ./gradlew lint

Run lint

./gradlew lintDebug

Debug only (faster)

./gradlew ktlintCheck

Kotlin style (if configured)

./gradlew detekt

Detekt analysis (if configured)

Clean & Refresh ./gradlew clean

Clean build

./gradlew clean assembleDebug

Clean + build

./gradlew --refresh-dependencies

Force dependency refresh

./gradlew --stop

Stop Gradle daemon

Dependencies ./gradlew dependencies

All dependencies

./gradlew app:dependencies

Module dependencies

./gradlew dependencyInsight --dependency < name

Signing Debug keystore location: Linux: ~/.android/debug.keystore macOS: ~/.android/debug.keystore Windows: C:\Users\.android\debug.keystore Password: android , Alias: androiddebugkey

Create release keystore

keytool -genkey -v -keystore release.keystore \ -alias my-key-alias -keyalg RSA -keysize 2048 -validity 10000 Performance ./gradlew assembleDebug --parallel

Parallel builds

./gradlew assembleDebug --build-cache

Use cache

./gradlew assembleDebug --offline

Offline mode

./gradlew --scan

Build scan (uploads data)

./gradlew --profile

Local profile report

gradle.properties Optimization org.gradle.jvmargs = -Xmx4g -XX:+HeapDumpOnOutOfMemoryError org.gradle.parallel = true org.gradle.caching = true org.gradle.configuration-cache = true android.useAndroidX = true SDK Management sdkmanager sdkmanager --list

List available packages

sdkmanager --list | grep system

Filter system images

sdkmanager "platform-tools"

Install package

sdkmanager "platforms;android-34"

Install platform

sdkmanager "system-images;android-34;google_apis;x86_64" sdkmanager --update

Update all

sdkmanager --licenses

Accept licenses

avdmanager avdmanager list device

List device profiles

avdmanager list avd

List created AVDs

Create AVD

avdmanager create avd -n my_avd \ -k "system-images;android-34;google_apis;x86_64" \ -d pixel_6 avdmanager delete avd -n my_avd Emulator CLI emulator -list-avds

List AVDs

emulator @my_avd

Start AVD

emulator @my_avd -no-snapshot

Fresh boot

emulator @my_avd -no-window

Headless

emulator @my_avd -wipe-data

Factory reset

ROM Building (AOSP/LineageOS) Environment Setup

Install repo tool

mkdir -p ~/.bin curl https://storage.googleapis.com/git-repo-downloads/repo

~/.bin/repo chmod a+x ~/.bin/repo export PATH = " $HOME /.bin: $PATH "

Initialize repo

mkdir android && cd android repo init -u https://github.com/LineageOS/android.git -b lineage-21.0

Or AOSP: repo init -u https://android.googlesource.com/platform/manifest

Sync source

repo sync -c -j $( nproc ) --force-sync --no-tags --no-clone-bundle Build Commands

Setup environment

source build/envsetup.sh

Select device

lunch < device

-userdebug

AOSP

breakfast < device

LineageOS

Build

m

Full build

mka bacon

LineageOS (with flashable zip)

mka bootimage

Just boot.img

mka systemimage

Just system

Parallel build

m -j $( nproc ) Build Variants Variant Purpose user Production, no root, limited debugging userdebug Like user + root + debugging eng Development, all debug tools Common Targets m bootimage

Kernel + ramdisk

m systemimage

System partition

m vendorimage

Vendor partition

m otapackage

OTA zip

mka bacon

LineageOS flashable zip

Module-specific

m Settings

Just Settings app

mm

Build current directory

mmm packages/apps/Settings

Build specific path

LineageOS Specifics breakfast < device

Setup + sync device deps

brunch < device

breakfast + mka bacon

Cherry-pick from Gerrit

repopick < change_number

repopick -t < topic

Sync specific project

repo sync packages/apps/Settings Build Output out/target/product// ├── boot.img # Kernel + ramdisk ├── system.img # System partition ├── vendor.img # Vendor partition ├── lineage-*.zip # Flashable zip (LineageOS) └── recovery.img # Recovery (non-A/B) Device Trees Structure device/// ├── AndroidProducts.mk # Product makefiles list ├── BoardConfig.mk # Board configuration ├── device.mk # Device makefile ├── lineage_.mk # LineageOS product ├── extract-files.sh # Vendor blob extraction ├── proprietary-files.txt # Blob list ├── sepolicy/ # SELinux policies └── overlay/ # Resource overlays Key Files BoardConfig.mk - Hardware configuration: TARGET_ARCH := arm64 TARGET_BOARD_PLATFORM := TARGET_BOOTLOADER_BOARD_NAME := BOARD_KERNEL_CMDLINE := ... BOARD_BOOT_HEADER_VERSION := 4 device.mk - Device packages: PRODUCT_PACKAGES += \ android.hardware.audio @ 7.0-impl \ audio.primary. $ ( TARGET_BOARD_PLATFORM ) PRODUCT_COPY_FILES += \ $ (LOCAL_PATH)/configs/audio_policy.conf : ... Kernel Building Standalone

Setup

export ARCH = arm64 export CROSS_COMPILE = aarch64-linux-gnu-

Or for Clang:

export CC = clang export CLANG_TRIPLE = aarch64-linux-gnu-

Configure

make < device

_defconfig

Build

make -j $( nproc )

Output

arch/arm64/boot/Image.gz In AOSP Tree

In BoardConfig.mk

TARGET_KERNEL_SOURCE := kernel// TARGET_KERNEL_CONFIG := _defconfig TARGET_KERNEL_CLANG_COMPILE := true Troubleshooting Common Gradle Issues

OOM

export GRADLE_OPTS = "-Xmx4g"

Daemon issues

./gradlew --stop rm -rf ~/.gradle/daemon

Cache issues

./gradlew clean --refresh-dependencies Common AOSP Issues

Ninja error - usually dependency issue

m clean && m

Jack server (old builds)

./prebuilts/sdk/tools/jack-admin kill-server ./prebuilts/sdk/tools/jack-admin start-server

SELinux issues

audit2allow -i audit.log Build Logs

Gradle

./gradlew assembleDebug --stacktrace ./gradlew assembleDebug --info

AOSP

m 2

&1 | tee build.log Quick Reference Gradle Task Command Build debug ./gradlew assembleDebug Build release ./gradlew assembleRelease Install ./gradlew installDebug Test ./gradlew test Lint ./gradlew lint Clean ./gradlew clean Dependencies ./gradlew dependencies AOSP/LineageOS Task Command Setup env source build/envsetup.sh Select device lunch -userdebug Full build m LineageOS zip mka bacon Just boot mka bootimage Sync repo sync -c -j$(nproc)