NDK 的helloworld步奏

1. helloworld.c

#include <string.h>

#include <jni.h>





/*

 * Class:     com_example_ndk_NativeHelloworld

 * Method:    hello

 * Signature: ()Ljava/lang/String;

 */

jstring JNICALL Java_com_example_ndk_NativeHelloworld_hello(JNIEnv * env, jclass thiz) {

    return (*env)->NewStringUTF(env, "HelloWorld! I am from JNI !");

}

 

2.Android.mk

LOCAL_PATH := $(call my-dir)  

  

include $(CLEAR_VARS)  

#LOCAL_MODULE

LOCAL_MODULE    := hello  

LOCAL_SRC_FILES := helloworld.c  

  

include $(BUILD_SHARED_LIBRARY) 

3.NativeHelloworld.java

package com.example.ndk;

import android.util.Log;

public class NativeHelloworld {
    public static native String hello();
    
    static {  
        Log.i("NativeClass","before load library");  
        System.loadLibrary("hello");//注意这里为自己指定的.so文件，无lib前缀，亦无后缀  
        Log.i("NativeClass","after load library");    
    }  
}

4.用ndk在项目目录里面编译出hello.so

本人是在linux系统下编译，放到eclipse的libs/armeabi下

5.调用方法，运行