<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent" ><TextViewandroid:id="@+id/activity_main_textview_hello"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_centerHorizontal="true"android:layout_centerVertical="true"tools:context=".MainActivity" /></RelativeLayout>

package com.example.hellojni;import android.os.Bundle;
import android.app.Activity;
import android.widget.TextView;public class MainActivity extends Activity {private TextView helloTextView;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);helloTextView = (TextView) findViewById(R.id.activity_main_textview_hello);}}

public native String hello();

static {System.loadLibrary("mylib");
}

helloTextView.setText(hello());

package com.example.hellojni;import android.os.Bundle;
import android.app.Activity;
import android.widget.TextView;public class MainActivity extends Activity {static {System.loadLibrary("mylib");}private TextView helloTextView;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);helloTextView = (TextView) findViewById(R.id.activity_main_textview_hello);helloTextView.setText(hello());}public native String hello();
}

javah -d http://www.cnblogs.com/jni/ -jni com.example.hellojni.MainActivity

#include "com_example_hellojni_MainActivity.h"JNIEXPORT jstring JNICALL Java_com_example_hellojni_MainActivity_hello(JNIEnv *env, jobject thiz) {return (*env) -> NewStringUTF(env, "Hello JNI!");
}

LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)LOCAL_MODULE := mylib
LOCAL_SRC_FILES := com_example_hellojni_MainActivity.cinclude $(BUILD_SHARED_LIBRARY)