Question

如何在多线程中使用JNI

Answer 1

JNIEnv* g_env;
jobject g_thiz;
JavaVM *g_jvm;
void* thread_get_str(void * argv) {
(g_jvm)->AttachCurrentThread(&g_env, NULL);
LOGE("log in another thread!!!!!!!!!!");
jclass clazz = (g_env)->GetObjectClass(g_thiz);
jfieldID fid = (g_env)->GetFieldID(clazz, "mInstanceName", "Ljava/lang/String;");
jstring jstr = (jstring)(g_env)->GetObjectField(g_thiz, fid);
LOGE("this message is from other thread of c++ %s", (g_env)->GetStringUTFChars(jstr, NULL));
(g_jvm)->DetachCurrentThread();
}

void threadTest(JNIEnv* env, jobject thiz) {
if (g_thiz) {
(g_env)->DeleteGlobalRef(g_thiz);
}
g_thiz = (env)->NewGlobalRef(thiz);
g_env = env;

pthread_t thread;

pthread_create(&thread, NULL, thread_get_str, NULL);

}