using UnityEngine;  using UnityEngine.UI;  using UnityEngine.EventSystems;    public class InputNavigator : MonoBehaviour, ISelectHandler, IDeselectHandler  {      EventSystem _system;      private bool _isSelect = false;        void Start()      {          _system = EventSystem.current;      }        void Update()      {          if (Input.GetKeyDown(KeyCode.Tab) && _isSelect)          {                Selectable next = null;              if (Input.GetKey(KeyCode.LeftShift) || Input.GetKey(KeyCode.RightShift))              {                  next = _system.currentSelectedGameObject.GetComponent
     
      ().FindSelectableOnUp();              }              else              {                  next = _system.currentSelectedGameObject.GetComponent
      
       ().FindSelectableOnDown();              }              if (next != null)              {                  InputField inputfield = next.GetComponent
       
        ();                  _system.SetSelectedGameObject(next.gameObject, new BaseEventData(_system));              }              else              {                  Debug.LogError("找不到下一个控件");              }          }      }        public void OnSelect(BaseEventData eventData)      {          _isSelect = true;      }        public void OnDeselect(BaseEventData eventData)      {          _isSelect = false;      }  }