The following steps work on Ubuntu 16.04.

1. Get source from https://github.com/guardianproject/Orfox.git

2. Install Android SDK 23, SDK Build-tools 23.0.1, Android Support Repository

3. Export ANDROID_HOME, ANDROID_NDK_HOME

4. In root folder, execute (note: if need to build modified code, first comment out the git part)

./make_build_release

5. If error “Could not find autoconf 2.13”, install autoconf-2.13 from source. e.g. on Ubuntu 16.04:

wget http://ftp.gnu.org/gnu/autoconf/autoconf-2.13.tar.gz
tar -xvzf autoconf-2.13.tar.gz
cd autoconf-2.13/
./configure --program-suffix=2.13
make
sudo make install'

6. If error “ccache not found”,

apt-get install ccache

1. https://git.torproject.org/orbot.git
(In Eclipse, Import Projects from Git -> select “Clone submodules” -> Import as general project)

2. Install automake, libtool

3. Export ANDOIR_NDK_HOME and ANDROID_HOME, then

export PATH=$ANDROID_HOME/tools:$PATH

4. In Android SDK manager, install SDK Platform API 23 Rev.3, and Extras -> Android Support Repository

5. In orbotservices/src/main, run

ndk-build

Otherwise there is error: “orbotservices/src/main/libs/armeabi/pdnsd” not found

6. In Orbot root directory, run

make -C external

7. Verify tor and polipo binaries

file external/bin/tor external/bin/polipo

8. In Orbot root diretory, build a debug APK (assuming target is Android 6.0)

android update project --name Orbot --target android-23 --path .
./gradlew assembleDebug

the APK is in app/build/outputs/apk/