Adding native C++ code to your application

#include <stdlib.h>
#include <jni.h>
#include <android/log.h>
#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, "App2", __VA_ARGS__))

extern "C"
{
  JNIEXPORT void JNICALL
Java_com_packtpub_ndkcookbook_app2_App2Activity_onCreateNative( JNIEnv* env, jobject obj )
    {
      LOGI( "Hello World!" );
    }
}

package com.packtpub.ndkcookbook.app2;

import android.app.Activity;
import android.os.Bundle;

public class App2Activity extends Activity
{
    static
    {

      System.loadLibrary( "App2" );
    }
    @Override protected void onCreate( Bundle icicle )
    {
      super.onCreate( icicle );
      onCreateNative();
    }
    public static native void onCreateNative();
};

TARGET_PLATFORM := android-7
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_ARM_MODE := arm
LOCAL_MODULE     := App2
LOCAL_SRC_FILES += Wrappers.cpp
LOCAL_ARM_MODE := arm
COMMON_CFLAGS := -Werror -DANDROID -DDISABLE_IMPORTGL \
-isystem $(SYSROOT)/usr/include/
ifeq ($(TARGET_ARCH),x86)
	LOCAL_CFLAGS   := $(COMMON_CFLAGS)
  else
	LOCAL_CFLAGS   := -mfpu=vfp -mfloat-abi=softfp \
  -fno-short-enums $(COMMON_CFLAGS)
endif
LOCAL_LDLIBS     := -llog -lGLESv2 -Wl,-s
LOCAL_CPPFLAGS += -std=gnu++0x
include $(BUILD_SHARED_LIBRARY)

APP_OPTIM := release
APP_PLATFORM := android-7
APP_STL := gnustl_static
APP_CPPFLAGS += -frtti 
APP_CPPFLAGS += -fexceptions
APP_CPPFLAGS += -DANDROID
APP_ABI := armeabi-v7a
APP_MODULES := App2
NDK_TOOLCHAIN_VERSION := clang

>ndk-build

Compile++ arm: App2 <= Wrappers.cpp
SharedLibrary: libApp2.so
Install      : libApp2.so => libs/armeabi-v7a/libApp2.so

>ant debug