unity Tab键实现切换输入框功能

搭建场景的时候用到输入框的时候就把脚本挂载上去即可，其他的什么都不需要管，就可以切换了
InputField挂载的脚本如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
/// <summary>
/// ************************************本脚本挂在输入框上即可*********************************************
/// </summary>
public class Tabcoll : MonoBehaviour, ISelectHandler, IDeselectHandler
{
    public void OnDeselect(BaseEventData eventData)
    {
        _instacnet = false;
    }

    public void OnSelect(BaseEventData eventData)
    {
        _instacnet = true;
    }
    EventSystem system;
    private bool _instacnet = false;
    // Use this for initialization
    void Start()
    {
        system = EventSystem.current;
    }

    // Update is called once per frame
    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Tab) && _instacnet)
        {
            Selectable _Nect = null;
            if (Input.GetKey(KeyCode.LeftShift) || Input.GetKey(KeyCode.RightShift))
            {
                _Nect = system.currentSelectedGameObject.GetComponent<Selectable>().FindSelectableOnUp();
                if (_Nect == null) _Nect = system.lastSelectedGameObject.GetComponent<Selectable>();

            }
            else
            {
                _Nect = system.currentSelectedGameObject.GetComponent<Selectable>().FindSelectableOnDown();
                if (_Nect == null) _Nect = system.firstSelectedGameObject.GetComponent<Selectable>();
            }
            if (_Nect != null)
            {
                InputField inputField = _Nect.GetComponent<InputField>();
                system.SetSelectedGameObject(_Nect.gameObject, new BaseEventData(system));
            }
            else
            {
                Debug.LogError("没有下一个组件");
            }
        }
    }

}