4

So I've been trying to call a java method from C++ without any luck. This is the error that I receive:

JNI ERROR (app bug): accessed stale local reference 0x5cb00019 (index 6 in a table of size 2) VM aborting Fatal signal 11 (SIGSEGV) at 0xdeadd00d (code=1)

Here is what I do in the code (java-side):

    public class Wrapper extends Activity{
        private native void initJNIBridge();
            static final String TAG = "Wrapper";

    protected void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);

            initJNIBridge(); // Calls C++ function.
    }

    public void upgradeAdFree() {
             Log.d(TAG, "Wrapper::upgradeAdFree()");
    }

And here is the C++ side:

    typedef struct JniMethodInfo_
    {
        JNIEnv *    env;
        jclass      classID;
        jmethodID   methodID;
    } JniMethodInfo;

    extern "C"
    {
static jobject javaObj;

// get env and cache it
static JNIEnv* getJNIEnv(void)
{

    JavaVM* jvm = cocos2d::JniHelper::getJavaVM();
    if (NULL == jvm) {
        LOGD("Failed to get JNIEnv. JniHelper::getJavaVM() is NULL");
        return NULL;
    }

    JNIEnv *env = NULL;
    // get jni environment
    jint ret = jvm->GetEnv((void**)&env, JNI_VERSION_1_4);

    switch (ret) {
        case JNI_OK :
            // Success!
            return env;

        case JNI_EDETACHED :
            // Thread not attached

            // TODO : If calling AttachCurrentThread() on a native thread
            // must call DetachCurrentThread() in future.
            // see: http://developer.android.com/guide/practices/design/jni.html

            if (jvm->AttachCurrentThread(&env, NULL) < 0)
            {
                LOGD("Failed to get the environment using AttachCurrentThread()");
                return NULL;
            } else {
                // Success : Attached and obtained JNIEnv!
                return env;
            }

        case JNI_EVERSION :
            // Cannot recover from this error
            LOGD("JNI interface version 1.4 not supported");
        default :
            LOGD("Failed to get the environment using GetEnv()");
            return NULL;
    }
}

// get class and make it a global reference, release it at endJni().
static jclass getClassID(JNIEnv *pEnv)
{
    jclass ret = pEnv->FindClass(CLASS_NAME);
    if (! ret)
    {
        LOGD("Failed to find class of %s", CLASS_NAME);
    }

    return ret;
}
static bool getMethodInfo(JniMethodInfo &methodinfo, const char *methodName, const char *paramCode)
{
    jmethodID methodID = 0;
    JNIEnv *pEnv = 0;
    bool bRet = false;

    do 
    {
        pEnv = getJNIEnv();
        if (! pEnv)
        {
            break;
        }

        jclass classID = getClassID(pEnv);

        methodID = pEnv->GetMethodID(classID, methodName, paramCode);
        if (! methodID)
        {
            LOGD("Failed to find method id of %s", methodName);
            break;
        }

        methodinfo.classID = classID;
        methodinfo.env = pEnv;
        methodinfo.methodID = methodID;


        bRet = true;
    } while (0);

    return bRet;
}   

JNIEXPORT void JNICALL Java_org_test_games_Wrapper_initJNIBridge(JNIEnv *, jobject jobj){
    LOGD("Java_org_test_games_Wrapper_initJNIBridge()");

    javaObj = jobj;

    return;
}

void upgradeAdFreeJNI()
{      
    LOGD("upgradeAdFreeJNI");

    JniMethodInfo methodInfo;
    if (! getMethodInfo(methodInfo, "upgradeAdFree", "()V"))
    {
        LOGD("Cannot find method!");
        return;
    }

    methodInfo.env->CallVoidMethod(javaObj, methodInfo.methodID);
}


}

Any suggestions here would be greatly appreciated as I've been stumped on this for a few days and its not the easiest task in the world to debug this.

Thanks

4

2 回答 2

4

问题是您指向作业的静态指针不再有效。您需要保护它免受任何垃圾收集器运行。这可以通过使用全局引用而不是本地引用来完成。而不是仅仅分配指针创建一个 globalRef。

JNIEXPORT void JNICALL Java_org_test_games_Wrapper_initJNIBridge(JNIEnv *, jobject jobj)
{
    LOGD("Java_org_test_games_Wrapper_initJNIBridge()");

    javaObj = env->NewGlobalRef(env, jobj);

return;
}

但请注意，您还必须释放 globafRef。

于 2013-02-12T16:27:33.913 回答
2

You must not simply store pointer to an object, as your error says. When you want to store it, you have to store local or global reference to object. See http://docs.oracle.com/javase/6/docs/technotes/guides/jni/spec/functions.html#global_local

Change to:

    JNIEXPORT void JNICALL Java_org_test_games_Wrapper_initJNIBridge(JNIEnv *env, jobject jobj){
        LOGD("Java_org_test_games_Wrapper_initJNIBridge()");

        javaObj = NewGlobalRef(env, jobj);

        return;
    }
于 2013-02-12T16:58:44.533 回答