1
我想編寫一個本地方法，它可以從套接字接收數據，然後寫回到從Java輸入參數的ByteArray。因爲我在Java端分配ByteArray，並將它傳遞給本地方法，所以我知道應該使用GetPrimitiveArrayCritical（）來獲取此ByteArray的指針。我使用一個名爲socket_loop_native_data的結構體的jbyteArray變量來記住這個輸入的ByteArray，並使用pthread_create（）以這個結構體作爲輸入參數啓動一個新的線程。Android JNI原生C++代碼GetPrimitiveArrayCritical（）問題
最後，在線程的主體代碼，我用GetPrimitiveArrayCritical（）來獲取先前的ByteArray的指針，但是失敗了......
錯誤日誌是：
14:09:32.350 Warning dalvikvm 2780 JNI WARNING: 0x4077ab48 is not a valid JNI reference
14:09:32.350 Warning dalvikvm 2780 in Ldalvik/system/NativeStart;.run()V (GetPrimitiveArrayCritical)
這件作品的我的本地代碼是像
struct socket_loop_native_data {
pthread_mutex_t thread_mutex;
pthread_t thread;
struct pollfd *pollData;
JavaVM *vm;
int envVer;
jobject me;
jbyteArray javaBuffer;
int bufferSize;
jbyte *nativeBuffer;
char *beginOfBuffer;
char *endOfBuffer;
int decodedDataSize;
bool running;
};
typedef socket_loop_native_data native_data_t;
static jfieldID field_mNativeDataSocket;
static inline native_data_t *get_native_data(JNIEnv *env, jobject object) {
return (native_data_t *)(env->GetIntField(object, field_mNativeDataSocket));
}
native_data_t *get_SocketLoop_native_data(JNIEnv *env, jobject object) {
return get_native_data(env, object);
}
JNIEXPORT void JNICALL Java_android_classInitNativeSocket(JNIEnv* env, jclass clazz) {
field_mNativeDataSocket = env->GetFieldID(clazz, "mNativeDataSocket", "I");
}
JNIEXPORT void JNICALL Java_android_initializeNativeDataNativeSocket(JNIEnv* env, jobject object) {
native_data_t *nat = (native_data_t *)calloc(1, sizeof(native_data_t));
if (NULL == nat) {
LOGD("%s: out of memory!", __FUNCTION__);
return;
}
memset(nat, 0, sizeof(native_data_t));
pthread_mutex_init(&(nat->thread_mutex), NULL);
env->SetIntField(object, field_mNativeDataSocket, (jint)nat);
}
JNIEXPORT jboolean JNICALL Java_android_startSocketLoopNative(JNIEnv *env, jobject object, jint sock, jbyteArray buffer, jint size) {
jboolean result = JNI_FALSE;
socket_loop_native_data *nat = get_native_data(env, object);
pthread_mutex_lock(&(nat->thread_mutex));
nat->running = false;
if (nat->pollData) {
LOGD("trying to start SocketLoop a second time!");
pthread_mutex_unlock(&(nat->thread_mutex));
return JNI_FALSE;
}
nat->pollData = (struct pollfd *)malloc(sizeof(struct pollfd));
if (!nat->pollData) {
LOGD("out of memory error starting SocketLoop!");
goto done;
}
memset(nat->pollData, 0, sizeof(struct pollfd));
nat->pollData[0].fd = sock;
nat->pollData[0].events = POLLIN;
env->GetJavaVM(&(nat->vm));
nat->envVer = env->GetVersion();
nat->me = env->NewGlobalRef(object);
nat->javaBuffer = buffer;
nat->bufferSize = (int)size;
nat->decodedDataSize = 0;
pthread_create(&(nat->thread), NULL, socketLoopMain, nat);
result = JNI_TRUE;
done:
if (JNI_FALSE == result) {
if (nat->me) env->DeleteGlobalRef(nat->me);
nat->me = NULL;
if (nat->pollData) free(nat->pollData);
nat->pollData = NULL;
}
pthread_mutex_unlock(&(nat->thread_mutex));
return result;
}
static void *socketLoopMain(void *ptr) {
native_data_t *nat = (native_data_t *)ptr;
JNIEnv *env;
JavaVMAttachArgs args;
char name[] = "SocketLoop";
args.version = nat->envVer;
args.name = name;
args.group = NULL;
nat->vm->AttachCurrentThread(&env, &args);
...
nat->nativeBuffer = (jbyte *)(env->GetPrimitiveArrayCritical((nat->javaBuffer), NULL));
nat->beginOfBuffer = (char *)(&(nat->nativeBuffer[0]));
nat->endOfBuffer = (char *)(&(nat->nativeBuffer[0])) + (nat->bufferSize);
...
}
的VM中止後，執行該語句
nat->nativeBuffer = (jbyte *)(env->GetPrimitiveArrayCritical((nat->javaBuffer), NULL));
因此...劑量這意味着我可以/不應該使用jbyteArray變量來記住輸入ByteArray並在另一個地方調用GetPrimitiveArrayCritical（）？
或者，我忘了做什麼？
任何建議將不勝感激！
解決方案：我應該使用NewGlobalRef（）。 –