package com.thisway.hardlibrary;

public class HardControl {

    public static native int ledCtrl(int which, int status);

    public static native int ledOpen();

    public static native void ledClose();

    static {

        try {

            System.loadLibrary("hardcontrol");

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}

sourceSets {

        main {

            jniLibs.srcDirs = ['libs']

        }

    }

#include <jni.h>    /* /usr/lib/jvm/java-1.7.0-openjdk-amd64/include/ */

#include <stdio.h>

#include <stdlib.h>

#include <android/log.h>  /* android log*/

#if 0

 typedef struct {

    char *name;          /* Java里调用的函数名 */

    char *signature;    /* JNI字段描述符, 用来表示Java里调用的函数的参数和返回值类型 */

    void *fnPtr;          /* C语言实现的本地函数 */

} JNINativeMethod;

#endif

jint ledOpen(JNIEnv *env, jclass cls)

{   __android_log_print(ANDROID_LOG_DEBUG, "JNIDemo", "native add ...");

    __android_log_print(ANDROID_LOG_DEBUG, "LEDDemo", "native ledOpen......");

    return ;

}

void ledClose(JNIEnv *env, jclass cls)

{

    __android_log_print(ANDROID_LOG_DEBUG, "LEDDemo", "native ledClose......");

}

jint ledCtrl(JNIEnv *env, jclass cls,jint which, jint status)

{

    __android_log_print(ANDROID_LOG_DEBUG, "LEDDemo", "native ledCtrl: %d,  %d",which, status);

    return ;

}

static const JNINativeMethod methods[] = {

    {"ledOpen", "()I", (void *)ledOpen},

    {"ledClose", "()V", (void *)ledClose},

    {"ledCtrl", "(II)I", (void *)ledCtrl},

};

/* System.loadLibrary */

JNIEXPORT jint JNICALL

JNI_OnLoad(JavaVM *jvm, void *reserved)

{

    JNIEnv *env;

    jclass cls;

    if ((*jvm)->GetEnv(jvm, (void **)&env, JNI_VERSION_1_4)) {

        return JNI_ERR; /* JNI version not supported */

    }

    cls = (*env)->FindClass(env, "com/thisway/hardlibrary/HardControl");

    if (cls == NULL) {

        return JNI_ERR;

    }

    /* 2. map hello java<-->c c_hello */

    if((*env)->RegisterNatives(env, cls, methods, sizeof(methods) / sizeof(methods[])) < )

        return JNI_ERR;

    return JNI_VERSION_1_4;

}

arm-linux-gcc -fPIC -shared hardcontrol.c -o libhardcontrol.so 
-I /usr/lib/jvm/java-1.7.0-openjdk-amd64/include/  
-nostdlib /work/android-5.0.2/prebuilts/ndk/9/platforms/android-19/arch-arm/usr/lib/libc.so 
-I /work/android-5.0.2/prebuilts/ndk/9/platforms/android-19/arch-arm/usr/include 
/work/android-5.0.2/prebuilts/ndk/9/platforms/android-19/arch-arm/usr/lib/liblog.so