下載後把壓縮包解壓出來，例如：D:\ndk，目錄下的ndk-build.cmd就是用來編譯的批處理命令。 這裡以D:\ndk\samples\hello-jni為例，開啟D:\ndk\samples\hello-jni\jni\hello-jni.c檢視程式碼：

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 
 
*/
#include <string.h>
#include <jni.h>

/* This is a trivial JNI example where we use a native method
 * to return a new VM String. See the corresponding Java source
 * file located at:
 *
 *   apps/samples/hello-jni/project/src/com/example/hellojni/HelloJni.java
 */
jstring
Java_com_example_hellojni_HelloJni_stringFromJNI( JNIEnv* env,
                                                  jobject thiz )
{
    return
 
 (*env)->NewStringUTF(env, "Hello from JNI !");
}

因為我們是拿這個c原始碼檔案來使用，如果遷就Java_com_example_hellojni_HelloJni_stringFromJNI 函式名的話，在我們的android工程中java類的宣告就要是：com/example/hellojni/HelloJni.java。 反之，如果我們的android工程已經建立好，並且包名是com.example.hellojni，stringFromJNI函式我們寫在了MainActivity.java類裡， 那麼這裡的c函式就要修改為：Java_com_example_hellojni_MainActivity_stringFromJNI，否則在尋找函式時會找不到。 然後執行命令：D:\ndk\ndk-build.cmd（如果設定過環境變數則直接使用ndk-build.cmd）來編譯hello-jni，如果沒有錯誤會輸出： Gdbserver      : [arm-linux-androideabi-4.6] libs/armeabi/gdbserver Gdbsetup       : libs/armeabi/gdb.setup
"Compile thumb : hello-jni <= hello-jni.c
SharedLibrary  : libhello-jni.so
Install        : libhello-jni.so => libs/armeabi/libhello-jni.so
編譯成功會在D:\ndk\samples\hello-jni\libs\armeabi目錄下生成libhello-jni.so檔案。 三、建立android應用程式並使用so檔案 開啟eclipse建立一個android應用程式HelloJni，預設的com.example.hellojni包下面有一個MainActivity.java， 在此包下新增一個HelloJni.java，

package com.example.hellojni;

public class HelloJni {
    public native String  stringFromJNI();    
    /* This is another native method declaration that is *not*     
     * implemented by 'hello-jni'. This is simply to show that     
     * you can declare as many native methods in your Java code     
     * as you want, their implementation is searched in the     
     * currently loaded native libraries only the first time     
     * you call them.     
     *     
     * Trying to call this function will result in a     
     * java.lang.UnsatisfiedLinkError exception !     */  
}

MainActivity.java修改為：

package com.example.hellojni;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.TextView;
import android.util.Log;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.activity_main);        
        HelloJni jni = new HelloJni();
        TextView  tv = new TextView(this); 
        String str = jni.stringFromJNI();
        Log.d("HelloJni", str);
        tv.setText(str);  
        setContentView(tv);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    static {  
        System.loadLibrary("hello-jni");           
    }
}

把編譯生成的libhello-jni.so檔案複製到F:\eclipse_workspace\HelloJni\libs\armeabi目錄下（armeabi如果不存在則手動建立之），然後編譯執行，效果圖如下：
參考資料：