jutils

Shared toolbox for native java libraries.

Android CMake Integration

The following will explain how to integrate the jutils library into your native android code.

CMake Integration

The easiest approach is to simply add the jutils folder with the CMake command add_subdirectory.

add_subdirectory("/path/to/jutils" jutils)
target_link_libraries(<my_target> steinwurf::jutils)

Where <my_target> is replaced by your target.

Doing so will make Android Studio/Gradle build jutils which means when a new platform is added or remove this change will automatically be mitigated.

The downside of this is that your build may end up taking longer - this can be a problem if you find yourself rebuilding your application frequently.

As a Pre-built Static Library

If the above approach doesn't fit your use case, an alternative is to pre-build the jutils library and depend on that in your application.

Note

This guide is written using Linux command-line tools and with the assumption that your android studio has been setup for native development.

To do so, first you need to build the jutils library for the desired platforms.

Here we'll assume you need the following ABIs:

• arm64-v8a
• armeabi-v7a
• x86
• x86_64

git clone git@github.com:steinwurf/jutils.git

cd jutils

Download CMake using Android Studio, and use it to build the various version of the library:

mkdir cmake_build && cd cmake_build

# arm64-v8a
~/Android/Sdk/cmake/3.18.1/bin/cmake -DCMAKE_TOOLCHAIN_FILE=~/Android/Sdk/ndk-bundle/build/cmake/android.toolchain.cmake -DANDROID_ABI="arm64-v8a" ../
~/Android/Sdk/cmake/3.18.1/bin/cmake --build . && cd ..
cp libjutils.a /path/to/your/android_app/app/src/main/cpp/libs/arm64-v8a

# armeabi-v7a
~/Android/Sdk/cmake/3.18.1/bin/cmake -DCMAKE_TOOLCHAIN_FILE=~/Android/Sdk/ndk-bundle/build/cmake/android.toolchain.cmake -DANDROID_ABI="armeabi-v7a" ../
~/Android/Sdk/cmake/3.18.1/bin/cmake --build . && cd ..
cp libjutils.a /path/to/your/android_app/app/src/main/cpp/libs/armeabi-v7a

# x86
~/Android/Sdk/cmake/3.18.1/bin/cmake -DCMAKE_TOOLCHAIN_FILE=~/Android/Sdk/ndk-bundle/build/cmake/android.toolchain.cmake -DANDROID_ABI="x86" ../
~/Android/Sdk/cmake/3.18.1/bin/cmake --build . && cd ..
cp libjutils.a /path/to/your/android_app/app/src/main/cpp/libs/x86

# x86_64
~/Android/Sdk/cmake/3.18.1/bin/cmake -DCMAKE_TOOLCHAIN_FILE=~/Android/Sdk/ndk-bundle/build/cmake/android.toolchain.cmake -DANDROID_ABI="x86" ../
~/Android/Sdk/cmake/3.18.1/bin/cmake --build . && cd ..
cp libjutils.a /path/to/your/android_app/app/src/main/cpp/libs/x86_64

cd ..

Copy the jutils public headers:

cp src/jutils/*.hpp /path/to/your/android_app/app/src/main/cpp/libs/include/jutils/

And finally here's how to set it up your CMakeLists.txt file in Android Studio:

add_library(jutils STATIC IMPORTED)
set_property(TARGET jutils PROPERTY IMPORTED_LOCATION
${CMAKE_SOURCE_DIR}/libs/${ANDROID_ABI}/libjutils.a)

include_directories(${CMAKE_SOURCE_DIR}/libs/include)

target_link_libraries(<your_target> jutils)

You should now be able to use jutils in your native code.

Running Unit Tests

Follow the step in the previous section for the platform where you wish to run the tests.

Now copy over the unit test executable with adb:

adb push /path/to/built/unit/test/jutils_test /data/local/tmp

Run the test:

adb shell /data/local/tmp/jutils_test