c++回调java方法

static JavaVM* g_JavaVM = NULL;
static jobject g_InterfaceObject = 0;
static const char *g_JavaClassName = "xxx/xxx/xxxx/Provider";

static void GetInterfaceObject(JNIEnv *env, const char *path, jobject *objptr)
{
    jclass cls = env->FindClass(path);
    if (!cls)
    {
        return;
    }
    jmethodID constr = env->GetMethodID(cls, "<init>", "()V");
    if (!constr)
    {
        return;
    }
    jobject obj = env->NewObject(cls, constr);
    if (!obj)
    {
        return;
    }
    (*objptr) = env->NewGlobalRef(obj);
}

jint JNI_OnLoad(JavaVM *vm, void *reserved)
{
    g_JavaVM = vm;

    JNIEnv *env;
    if (vm->GetEnv((void**) &env, JNI_VERSION_1_6) != JNI_OK)
    {
        return -1;
    }

    GetInterfaceObject(env, g_JavaClassName, &g_InterfaceObject);

    return JNI_VERSION_1_6;

}

static jobject getInstance(JNIEnv *env, jclass obj_class)
{
    jmethodID  c_id = env->GetMethodID(obj_class, "<init>", "()V");
    jobject obj = env->NewObject(obj_class, c_id);
    return obj;
}

void ConnectSuccessNotice(const int nWidth, const int nHeight, const int nFps)
{
    if (g_JavaVM == NULL)
    {
        return;
    }
    int status;
    JNIEnv *env = NULL;
    bool isAttached = false;

    status = g_JavaVM->GetEnv((void**) &env, JNI_VERSION_1_6);

    if (status < 0)  //
   {
        status = g_JavaVM->AttachCurrentThread(&env, NULL);
        if (status < 0)
        {
            return;
        }
        isAttached = true;
    }

    if (isAttached)  // 
    {
        jclass cls = env->GetObjectClass(g_InterfaceObject);
        if (cls != 0)
        {
            jmethodID mid = env->GetStaticMethodID(cls, "ConnectSuccessNoticeJavaThread", "(III)V");
            if (mid != 0)
            {
                env->CallStaticVoidMethod(cls, mid, nWidth, nHeight, nFps);
            }
        }
        g_JavaVM->DetachCurrentThread();
    }
    else  // 
    {
        jclass cls = env->FindClass(g_JavaClassName);
        if (cls != 0)
        {

            jobject obj = getInstance(env, cls);
            jmethodID mid = env->GetMethodID(cls, "ConnectSuccessNoticeJava", "(III)V");
            if (mid != 0)
            {
                env->CallVoidMethod(obj, mid, nWidth, nHeight, nFps);
            }
        }
    }

}


void OnDisconnectedNotice()
{
    if (g_JavaVM == NULL)
    {
        return;
    }
    int status;
    JNIEnv *env = NULL;
    bool isAttached = false;

    status = g_JavaVM->GetEnv((void**) &env, JNI_VERSION_1_6);


    if (status < 0)
   {
        status = g_JavaVM->AttachCurrentThread(&env, NULL);
        if (status < 0)
        {
            return;
        }
        isAttached = true;
    }

    if (isAttached)  // 
    {
        jclass cls = env->GetObjectClass(g_InterfaceObject);
        if (cls != 0)
        {
            jmethodID mid = env->GetStaticMethodID(cls, "OnDisconnectedJavaThread", "()V");
            if (mid != 0)
            {
                env->CallStaticVoidMethod(cls, mid);
            }
        }
        g_JavaVM->DetachCurrentThread();
    }
    else  // 
    {
        jclass cls = env->FindClass(g_JavaClassName);
        if (cls != 0)
        {

            jobject obj = getInstance(env, cls);
            jmethodID mid = env->GetMethodID(cls, "OnDisconnectedJava", "()V");
            if (mid != 0)
            {
                env->CallVoidMethod(obj, mid);
            }
        }
    }

}

void ReceiveDataCallback(const char *nbuff,const int nLength,const int nKey, const int nTimeStamp, string sDeviceID)
{

    if (g_JavaVM == NULL)
    {
        return;
    }
    int status;
    JNIEnv *env = NULL;
    bool isAttached = false;

    status = g_JavaVM->GetEnv((void**) &env, JNI_VERSION_1_6);

    if (status < 0)  //
   {
        status = g_JavaVM->AttachCurrentThread(&env, NULL);
        if (status < 0)
        {
            return;
        }
        isAttached = true;
    }

    if (isAttached)  
    {

        jclass cls = env->GetObjectClass(g_InterfaceObject);
        if (cls != 0)
        {
            jmethodID mid = env->GetStaticMethodID(cls, "ReceiveDataCallbackJavaThread", "(Ljava/lang/String;III[B)V");
            if (mid != 0)
            {
                jbyteArray jBufferArray = env->NewByteArray(nLength);
                jbyte *jby =env->GetByteArrayElements(jBufferArray, 0);

                memcpy(jby, nbuff, nLength);

                env->SetByteArrayRegion(jBufferArray, 0, nLength, jby);

                jstring jsDeviceID = env->NewStringUTF(sDeviceID.c_str());

                env->CallStaticVoidMethod(cls, mid,jsDeviceID, nLength, nKey, nTimeStamp,jBufferArray);

                env->ReleaseByteArrayElements(jBufferArray,jby,0);

                env->DeleteLocalRef(jBufferArray);
            }
        }
        g_JavaVM->DetachCurrentThread();
    }
    else  // PrintNdkLog不是在线程中被调用, 调用Java类成员API
    {

        jclass cls = env->FindClass(g_JavaClassName);
        if (cls != 0)
        {

            jobject obj = getInstance(env, cls);
            jmethodID mid = env->GetMethodID(cls, "ReceiveDataCallbackJava", "(Ljava/lang/String;III[B)V");
            if (mid != 0)
            {
                jbyteArray jBufferArray = env->NewByteArray(nLength);

                jbyte *jby =env->GetByteArrayElements(jBufferArray, 0);

                memcpy(jby, nbuff, nLength);

                env->SetByteArrayRegion(jBufferArray, 0, nLength, jby);

                jstring jsDeviceID = env->NewStringUTF(sDeviceID.c_str());

                env->CallVoidMethod(obj, mid,jsDeviceID, nLength, nKey, nTimeStamp,jBufferArray);

                env->ReleaseByteArrayElements(jBufferArray,jby,0);

                env->DeleteLocalRef(jBufferArray);
            }
        }
    }
}