roller for little vGL

• 滾動選擇回調

  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);
      }
  }

• roller控件實現

  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);
  }

• 調用roller_demo函數，編譯運行