1.导入管理器代码
2.制作面板预制物
3.UIPanelType注册一个名字
4.配置路径
5.UIManager.Instance.PushPanel(UIPanelType.xxxPanel)
6.面板预制物添加BasePanel（让管理器管理面板预制物）
7.面板预制物添加CanvasGroup（让面板透明）

UIManager的管理类

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class UIManager
{

    private static UIManager _instance;
    private Transform canvasTransform;
    private UIPanelTypeJson json;

    //打开的顺序   
    Stack<BasePanel> PanelStack = new Stack<BasePanel>();
    private Dictionary<UIPanelType, GameObject> PanelCach = new Dictionary<UIPanelType, GameObject>();



    public static UIManager GetInstance()
    {
        if (_instance == null)
        {
            _instance = new UIManager();
        }
        return _instance;
    }

    UIManager() {
        ParseUIPanelTypeJson();
        //canvasTransform = FindObjectOfType<Canvas>().transform;
        canvasTransform = GameObject.Find("Canvas").transform;

    }



    //显示出一个面板panel
    public void PushPanel(UIPanelType panelType)
    {
        if (PanelStack.Count != 0)
        {
            PanelStack.Peek().OnPause();
        }
        BasePanel panel = GetPanel(panelType);
        //Debug.Log("**************");
        PanelStack.Push(panel);
        panel.OnEnter();
    }

    public void PopPanel()
    {
        if (PanelStack.Count == 0)
        {
            return;
        }
        BasePanel panel = PanelStack.Pop();
        panel.OnExit();
        if (PanelStack.Count !=0 )
        {
            PanelStack.Peek().OnResume();
        }
    }

    //解析 UIPanelTypeJson
    private void ParseUIPanelTypeJson()
    {
        //加载json文件
        TextAsset t = Resources.Load<TextAsset>("UIPanelType");
        //Debug.Log(t.text);

        json = JsonUtility.FromJson<UIPanelTypeJson>(t.text);
    }

    private BasePanel GetPanel(UIPanelType panelType)
    {
        GameObject instPanel = PanelCach.TryGetValueBy(panelType);


        if (instPanel == null)
        {
            //通过名字找path
            string path = "";
            //Debug.Log(JsonUtility.ToJson(json));
            foreach (var item in json.PanelList)
            {
                //判断panel名字是否相同
                if (item.PanelName==panelType.ToString())
                {
                    path = item.PanelPath;
                }               
            }
            instPanel = GameObject.Instantiate(Resources.Load(path)) as GameObject;
            if (canvasTransform == null)
            {
                canvasTransform = GameObject.Find("Canvas").transform;
                PanelCach.Clear();
            }
            instPanel.transform.SetParent(canvasTransform,false);
            
            PanelCach.Add(panelType,instPanel);
            //Debug.Log("新创建panel");
        }
        else
        {
            //Debug.Log("用的缓存panel");
        }
        return instPanel.GetComponent<BasePanel>();
    }
}

//序列化
[Serializable]
public class UIPanelTypeJson
{
    public UIPanelInfo[] PanelList;
}
//序列化
[Serializable]
public class UIPanelInfo
{
    public string PanelName;
    public string PanelPath;

}

UIPanelType枚举类

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public enum UIPanelType {

    MainPanel, DlgRoot,
    GameOverPanel, StartPanel,
    GamePanel, SignPanel,
    AboutPanel, AudioPanel,
    EquipPanel, HelpPanel,
    SettingPanel, WelcomPanel,
    MapPanel, SettlementPanel,
    RecoveryPanel, ShopPanel,
    TaskPanel, AddScoreImagePanel,
    HeroPanel, RankingPanel,
    DailyRewardPanel,

}

BasePanel 所有的UIPanel都继承此类

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class BasePanel : MonoBehaviour {

    protected CanvasGroup canvas;

    private UIAnim anim;

    private void Start()
    {
        //anim = GetComponent<UIAnim>();
        //Debug.Log("GetComponent<UIAnim>().OnEnter();"+ anim.name);
    }
    public virtual void OnEnter()
    {
        //Debug.Log("OnEnter:open");
        if (canvas == null)
        {
            canvas = GetComponent<CanvasGroup>();
        }

        if (GetComponent<UIAnim>() != null)
        {
            GetComponent<UIAnim>().OnEnter();

        }


        canvas.alpha = 1;
        canvas.blocksRaycasts = true;




    }

    public virtual void OnExit()
    {
        //Debug.Log("OnExit:close");
        canvas.alpha = 0;
        canvas.blocksRaycasts = false;
    }

    public virtual void OnPause()
    {
        //Debug.Log("OnPause");

    }

    public virtual void OnResume()
    {
        //Debug.Log("OnResume");

    }  
}

json文件放在Resources文件夹下如图

UIjson脚本.PNG

Resources下也放入面板预制物方便动态加载