下载后把压缩包解压出来，例如：D:\ndk，目录下的ndk-build.cmd就是用来编译的批处理命令。

这里以D:\ndk\samples\hello-jni为例，打开D:\ndk\samples\hello-jni\jni\hello-jni.c查看代码：

/** 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

#include

/*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 !");

}

因为我们是拿这个c源码文件来使用，如果迁就Java_com_example_hellojni_HelloJni_stringFromJNI

函数名的话，在我们的android工程中java类的声明就要是：com/example/hellojni/HelloJni.java。

反之，如果我们的android工程已经创建好，并且包名是com.example.hellojni，stringFromJNI函数我们写在了MainActivity.java类里，

那么这里的c函数就要修改为：Java_com_example_hellojni_MainActivity_stringFromJNI，否则在寻找函数时会找不到。

然后执行命令：D:\ndk\ndk-build.cmd(如果设置过环境变量则直接使用ndk-build.cmd)来编译hello-jni，如果没有错误会输出：

Gdbserver      : [arm-linux-androideabi-4.6] libs/armeabi/gdbserver

Gdbsetup       : libs/armeabi/gdb.setup"Compile thumb : hello-jni <= hello-jni.cSharedLibrary  : libhello-jni.soInstall        : libhello-jni.so => libs/armeabi/libhello-jni.so

编译成功会在D:\ndk\samples\hello-jni\libs\armeabi目录下生成libhello-jni.so文件。

三、创建android应用程序并使用so文件

打开eclipse创建一个android应用程序HelloJni，默认的com.example.hellojni包下面有一个MainActivity.java，

在此包下添加一个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修改为：

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");

}

}

把编译生成的libhello-jni.so文件复制到F:\eclipse_workspace\HelloJni\libs\armeabi目录下(armeabi如果不存在则手动创建之)，然后编译运行，效果图如下：

参考资料：