Working with NanoPC-T4 and build the SerialPortDemo with libfriendlyarm-hardware.so in Android Studio.

The steps:
-Create Android Studio project
-Add the library libfriendlyarm-hardware.so under /src/main/jniLibs/armeabi
-Add build.gradle:
sourceSets.main {
jniLibs.srcDir 'src/main/libs' }
- Call in OnCreate() :
devfd = HardwareControler.openSerialPort( devName, speed, dataBits, stopBits );

Error: The app crashes with error:
No implementation found for int com.test.HardwareControler.openSerialPort()

Are there any sample projects for libfriendlyarm-hardware.so in Android Studio ?