LMK.JAVAIO is a JAVA GPIO library which supports LeMaker Guitar board. If we want to use it in your Android system, we need copy the library code to android source code tree and compile it .

Download the Guitar Android source code into your workspace:

cd your_workspace/
git clone https://github.com/LeMaker/android-actions.git ` 

Download the Guitar JAVA GPIO library into your workspace:

git clone https://github.com/LeMaker/LMK.JAVAIO.git

cd android-actions/android/
source build/envsetup.sh
lunch 

Copy the JAVA GPIO library code into android source code (in android-actions/android/system/ directory)

cp -rf ../../LMK.JAVAIO/hardware  system/

Compile the JAVA GPIO library:

cd system/hardware/
mm -j8  
cd system/hardware/jni/
mm -j8  

After that we will make out lmkhardwarejni.so in android-actions/android/out/target/product/lemaker_guitar_bbb/system/lib/ directory, then we can use adb tool to push it to Guitar on-board Android system directory /system/lib/.