roller for little vGL

static void roller_event_handler(lv_obj_t* obj, lv_event_t event)
{
    if (event == LV_EVENT_VALUE_CHANGED)
    {
        char buf[32];
        lv_roller_get_selected_str(obj, buf, sizeof(buf));
        printf("Selected month:%s\n", buf);
    }
}

void roller_demo(void)
{
    lv_obj_t* roller1 = lv_roller_create(lv_scr_act(), NULL);
    lv_roller_set_options(roller1,
        "Jan\n"
        "Feb\n"
        "Mar\n"
        "Apr\n"
        "May\n"
        "Jun\n"
        "Jul\n"
        "Aug\n"
        "Sep\n"
        "Oct\n"
        "Nov\n"
        "December",
        LV_ROLLER_MODE_INIFINITE
        );
    lv_roller_set_visible_row_count(roller1, 3);
    lv_obj_align(roller1, NULL, LV_ALIGN_CENTER, 0, 0);
    lv_obj_set_event_cb(roller1, roller_event_handler);
}