JNI c/cpp call java function or get value

Call JNI int func(void):
jobject getIden = env->GetMethodID(surfaceClass, "getIdentity", "()I");
jint iden = env->CallIntMethod(surface, getIden);
LOGD("jianwang --------getSurface identity =%d\n", (int)iden);

Get string:

jfieldID jfd = env->GetFieldID(surfaceClass, "mName", "Ljava/lang/String;");
jstring jstr = (jstring)env->GetObjectField(surface, jfd);
if (jstr) {
const char* icount = env->GetStringUTFChars(jstr, 0);
LOGD("jianwang --------getSurface icount=%s\n", icount);
env->ReleaseStringUTFChars(jstr, icount);
} else
LOGD("jianwang -------- jstr == NULL \n");


Get static int:

gSurfaceJavaGlue.count = env->GetStaticFieldID(surfaceClass, "GPU", "I");
jint icount = env->GetStaticIntField(surfaceClass, gSurfaceJavaGlue.count);