static void event_cb(lv_event_t * e)
{
lv_obj_t * obj = lv_event_get_target(e);
uint32_t id = lv_btnmatrix_get_selected_btn(obj);
bool prev = id == 0 ? true : false;
bool next = id == 6 ? true : false;
if(prev || next) {
/Find the checked button/
uint32_t i;
for(i = 1; i < 7; i++) {
if(lv_btnmatrix_has_btn_ctrl(obj, i, LV_BTNMATRIX_CTRL_CHECKED)) break;
}

    if(prev && i > 1) i--;
    else if(next && i < 5) i++;

    lv_btnmatrix_set_btn_ctrl(obj, i, LV_BTNMATRIX_CTRL_CHECKED);
}

}

/**

• Make a button group (pagination)
  */
  void lv_example_btnmatrix_3(void)
  {
  static lv_style_t style_bg;
  lv_style_init(&style_bg);
  lv_style_set_pad_all(&style_bg, 0);
  lv_style_set_pad_gap(&style_bg, 0);
  lv_style_set_clip_corner(&style_bg, true);
  lv_style_set_radius(&style_bg, LV_RADIUS_CIRCLE);
  lv_style_set_border_width(&style_bg, 0);

  static lv_style_t style_btn;
  lv_style_init(&style_btn);
  lv_style_set_radius(&style_btn, 0);
  lv_style_set_border_width(&style_btn, 1);
  lv_style_set_border_opa(&style_btn, LV_OPA_50);
  lv_style_set_border_color(&style_btn, lv_palette_main(LV_PALETTE_GREY));
  lv_style_set_border_side(&style_btn, LV_BORDER_SIDE_INTERNAL);
  lv_style_set_radius(&style_btn, 0);

  static const char * map[] = {LV_SYMBOL_LEFT, “1”, “2”, “3”, “4”, “5”, LV_SYMBOL_RIGHT, “”};

  lv_obj_t * btnm = lv_btnmatrix_create(lv_scr_act());
  lv_btnmatrix_set_map(btnm, map);
  lv_obj_add_style(btnm, &style_bg, 0);
  lv_obj_add_style(btnm, &style_btn, LV_PART_ITEMS);
  lv_obj_add_event_cb(btnm, event_cb, LV_EVENT_VALUE_CHANGED, NULL);
  lv_obj_set_size(btnm, 225, 35);

  /Allow selecting on one number at time/
  lv_btnmatrix_set_btn_ctrl_all(btnm, LV_BTNMATRIX_CTRL_CHECKABLE);
  lv_btnmatrix_clear_btn_ctrl(btnm, 0, LV_BTNMATRIX_CTRL_CHECKABLE);
  lv_btnmatrix_clear_btn_ctrl(btnm, 6, LV_BTNMATRIX_CTRL_CHECKABLE);

  lv_btnmatrix_set_one_checked(btnm, true);
  lv_btnmatrix_set_btn_ctrl(btnm, 1, LV_BTNMATRIX_CTRL_CHECKED);

  lv_obj_center(btnm);

}