build_all_android is an all-in-one build script that allows you to build, install and run native (C/C++) Android apps from the command line. This is ideal for build automation, but can also be in a developer’s compile/run loop.

In order to use this tool, all prerequisites should be installed.

Building Applications

By default build_all_android will build all Android projects under the current working directory. For example, from the command line, the following will change into the fplutil directory and build all Android projects:

cd fplutil

./bin/build_all_android -E dependencies

The application will place the build artifacts in the following locations:

APKs in fplutil/apks
Shared (.so) and Static (.a) libraries in fplutil/libs.

The following files are produced when building all Android targets in fplutil:

apks/example-release-unsigned.apk

apks/tests-release-unsigned.apk

Signing Applications

In order to install a release APK on a device it must be signed. By default build_all_android build but not sign release APKs. The -S or --sign_apk flag will enable signing of APKs.

For example, the following will build and sign all APKs with a temporary key:

cd fplutil

./bin/build_all_android -E dependencies -S

In a similar fashion to unsigned APKs, signed APKs are placed in the apks directory. Signed APK names do not end in -unsigned.apk.

apks/example-release-unsigned.apk
apks/example.apk
apks/tests-release-unsigned.apk
apks/tests.apk

Signing with Keys

The method described above generates a temporary key, which is used to sign the application. Using a temporary key is ok when debugging but should not be used when distributing your application to consumers as the application's certificate is used to validate it's origin and allow the application to be safely upgraded in future.

Firstly, a key needs to be generated using keytool which will be used to sign the application in future. The following generates a certificate referenced by the name my_alias in the keystore file my-release-key.keystore using the RSA algorithm with a lifetime of around 27.5 years (10000 days).

$ keytool -genkey -v -keystore my-release-key.keystore \

-alias my_alias -keyalg RSA -keysize 2048 -validity 10000

keytool will prompt for additional information required to generate the key and a password which is used to access the keystore file in future.

After saving the password supplied to keytool in a file (e.g mysecretpassword_file.txt), applications can be built and signed with build_all_android:

cd fplutil/examples/libfplutil_example
../../bin/build_all_android -S -k my-release-key.keystore \
                            -K my_alias
                            -P mysecretpassword_file.txt

The "Signing Your App Manually" section on Signing Your Applications describes in detail how to generate a private key using keytool and sign an application directly using jarsigner.

It is also possible to sign using a private / public key pair (pk8 / pem) using the --apk_keypk8 and --apk_keypem arguments of build_all_android. For information on how to generate pk8 / pem files see How to Sign APK Zip Files.

Installing Applications

Using the -i or --apk_install flag, build_all_android can install applications to one or more devices attached to a workstation.

For example, the following will build all Android applications in fplutil, sign the APKs and install them to an attached device:

cd fplutil

./bin/build_all_android -E dependencies -S -i

Running Applications

build_all_android will run applications on an attached Android device when the -r or --apk_run flag is specified.

For example, the following will build all Android applications in fplutil, sign the APKs, install them to an attached device and then execute them in sequence:

cd fplutil

./bin/build_all_android -E dependencies -S -i -r

Build Configuration

By default build_all_android will build all applications in release mode. It's possible to select the debug with the -T or --ant_target flag.

For example, the following will build all fplutil applications in debug mode with no native (C/C++) symbols:

cd fplutil

./bin/build_all_android -E dependencies -T debug

In order to perform symbolic debugging of native (C/C++) components with ndk-gdb NDK_DEBUG=1 must be passed to ndk-build. Arguments are passed to ndk-build using the -f or --make_flags flag.

For example:

cd fplutil

./bin/build_all_android -E dependencies -T debug -f NDK_DEBUG=1

To force optimization in debug mode, set NDK_DEBUG=0.

cd fplutil

./bin/build_all_android -E dependencies -T debug -f NDK_DEBUG=0

Cleaning Build Artifacts

Build artifacts can be cleaned using the -c or --clean flag. For example:

./bin/build_all_android -E dependencies -c

Working with Multiple Devices

By default, build_all_android will only install or run applications on one connected device. It's possible to select the set of devices using -d followed by a list of device serial numbers or @ which selects all devices attached to the workstation.

For example, the following will build all Android applications in fplutil, sign them, install and run them on all attached devices:

cd fplutil

./bin/build_all_android -E dependencies -S -i -r -d @