See Compiling for Android and Exporting for Android official documentation for details.
export ANDROID_HOME=/path/to/android-sdk
export ANDROID_NDK_ROOT=/path/to/android-ndk
# Release templates
scons platform=android target=release tools=no android_arch=armv7
scons platform=android target=release tools=no android_arch=arm64v8
cd platform/android/java
./gradlew build
# apk located at bin/android_release.apk
# Debug templates
scons platform=android target=release_debug android_arch=armv7
scons platform=android target=release_debug android_arch=arm64v8
cd platform/android/java
./gradlew build
# apk located at bin/android_debug.apk