Convert float* to jfloatArray using JNI

Question

I obtain a float* in my c++ function and i need convert it in jfloatArray to return to my Java code.

How can i convert float* to jfloatArray?

Thanks

Answer 1

To convert float* to jfloatArray, you can use NewFloatArray,

You can use code below:

• Variable "data" is just simple example, so you can use your code.
• Also, modify com_your_packagename to your real packagename.
• You must change dot of your package name to underbar. (com.your.packagename --> com_your_packagename)

---

jfloatArray Java_com_your_packagename_farrayFromJNI(JNIEnv *env, jobject thiz) {
    jfloatArray result;
    result = (*env)->NewFloatArray(env, 3);

    float* data;
    data = malloc(sizeof(float) * 3);
    data[0] = 123;  data[1] = 456;  data[2] = 789;

    (*env)->SetFloatArrayRegion(env, result, 0, 3, data);
    free(data);

    return result;
}

OR

extern "C"
{
JNIEXPORT jfloatArray JNICALL Java_com_your_packagename_farrayFromJNI(JNIEnv *env, jobject thiz) {

jfloatArray result;
    result = env->NewFloatArray(3);

    float* data;
    data = malloc(sizeof(float) * 3);
    data[0] = 123;  data[1] = 456;  data[2] = 789;

    env->SetFloatArrayRegion(result, 0, 3, data);
    free(data);
    return result;
};
}