Return a 2D primitive array from C to Java from JNI/NDK

Question

I have found large amounts of documentation on how to generate a 2D primitive array in JNI and returning it to Java. But these pieces of information fail to describe how to

Answer 1

I've made a simple function for conversion:

jobjectArray getJNIArray(JNIEnv *env, jobject obj, const vector >& arr) {
    jclass floatClass = env->FindClass("[F"); //
    jsize height = arr.size();

    // Create the returnable 2D array
    jobjectArray jObjarray = env->NewObjectArray(height, floatClass, NULL);

    // Go through the first dimension and add the second dimension arrays
    for (unsigned int i = 0; i < height; i++) {
        jfloatArray floatArray = env->NewFloatArray(arr[i].size());
        env->SetFloatArrayRegion(floatArray, (jsize) 0, (jsize) arr[i].size(), (jfloat*) arr[i].data());
        env->SetObjectArrayElement(jObjarray, (jsize) i, floatArray);
        env->DeleteLocalRef(floatArray);
    }

    return jObjarray;
}