Building C++ in Android Studio

externalNativeBuild.gradle

externalNativeBuild{
   cmake{
        path "CMakeLists.txt"
    }
}

defaultConfig {
  externalNativeBuild {
    cmake {
      targets "target1", "target2"
      arguments "-DANDROID_TOOLCHAIN=clang"
      cFlags "-DTEST_C_FLAG1", "-DTEST_C_FLAG2"
      cppFlags "-DTEST_CPP_FLAG2", "-DTEST_CPP_FLAG2"
      abiFilters "armeabi-v7a", "armeabi"
    } 
  }
}

or

externalNativeBuild{
   ndkBuild{
        path "Android.mk"
    }
}

defaultConfig {
  externalNativeBuild {
    ndkBuild {
      targets "target1", "target2"
      arguments "NDK_APPLICATION_MK:=Application.mk"
      cFlags "-DTEST_C_FLAG1", "-DTEST_C_FLAG2"
      cppFlags "-DTEST_CPP_FLAG2", "-DTEST_CPP_FLAG2"
      abiFilters "armeabi-v7a", "armeabi"
    } 
  }
}