NDK configuration, default folders and paths

build.gradle

import org.apache.tools.ant.taskdefs.condition.Os

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:0.13.0'
    }
}
apply plugin: 'com.android.application'

repositories {
    jcenter()
}

android {
    compileSdkVersion 21
    buildToolsVersion "21.1.1"

    defaultConfig {
        applicationId "com.example.myappgradle.app"
        minSdkVersion 9
        targetSdkVersion 19
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            runProguard false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    sourceSets {
        main{
            jniLibs.srcDir 'src/main/libs'
            //jniLibs
            //jni.srcDirs 'src/main/jni'
        }
    }
}

task ndkBuild(type: Exec,description: 'Compile JNI source via NDK'){
    println('executing ndkBuild')
    //read local.properties file
    def ndkBuildPath = project.plugins.findPlugin('com.android.application').getNdkFolder().absolutePath + File.separator
//or com.android.library
    if (Os.isFamily(Os.FAMILY_WINDOWS)) {
        ndkBuildPath +='ndk-build.cmd'
    } else {
        ndkBuildPath +='ndk-build'
    }

    commandLine ndkBuildPath, '-C', file('src/main/jni').absolutePath
    //'NDK_PROJECT_PATH=build','APP_BUILD_SCRIPT=src/main/jni/Android.mk'//force using appropriate Makefile

}
tasks.withType(JavaCompile){
    compileTask -> compileTask.dependsOn ndkBuild
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:21.0.3'
}