/* 
    那天看了SIKI的一個UI框架，他是用到了json解析，感覺有點繁瑣，對於新增需求或者需求變動，所更改的內容比較多： 
    1、需要更改json文字  2、需要更改對應的列舉型別。所以自己又總結了一個簡單的，只需要增加或者更改UIPanelPath即可， 
    裡面都是存放著對應的Resources資料夾下的UI面板路徑 
 */  
using UnityEngine;  
using System.Collections;  
using System.Collections.Generic;  
  
/// <summary>  
/// UI管理器，用於管理所有面板的顯示和隱藏  
/// </summary>  
public class UIManager{  
  
    private static UIManager instance;  
    public static UIManager Instance  
    {  
        get  
        {  
            if (instance==null)  
            {  
                instance = new UIManager();  
            }  
            return instance;  
        }  
    }  
  
    private UIManager()  
    {  
        Init();  
    }  
  
    private Transform canvasTransform;  
    private Transform CanvasTransform  
    {  
        get  
        {  
            if (canvasTransform==null)  
            {  
                canvasTransform = GameObject.Find("Canvas").transform;  
            }  
            return canvasTransform;  
        }  
    }  
    private Dictionary<string, BasePanel> panelDict;    //儲存例項化面板的字典  
    private Stack<BasePanel> panelStack;    //儲存面板的棧  
  
    /// <summary>  
    /// 獲取面板  
    /// </summary>  
    private BasePanel GetPanel(string panelPath)  
    {  
        BasePanel panel;  
        panelDict.TryGetValue(panelPath, out panel);  
        if (panel==null)  
        {  
            GameObject insObj = GameObject.Instantiate(Resources.Load(panelPath)) as GameObject;  
            insObj.transform.SetParent(CanvasTransform, false);  
            BasePanel basePanel = insObj.GetComponent<BasePanel>();  
            panelDict.Add(panelPath, basePanel);  
            return basePanel;  
        }  
        else  
        {  
            return panel;  
        }  
    }  
  
    /// <summary>  
    /// 初始化對應的字典和棧  
    /// </summary>  
    private void Init()  
    {  
        if (panelDict == null)  
            panelDict = new Dictionary<string, BasePanel>();  
        if (panelStack == null)  
            panelStack = new Stack<BasePanel>();  
    }  
  
    /// <summary>  
    /// 入棧，顯示面板  
    /// </summary>  
    /// <param name="panelPath"> 面板的路徑 </param>  
    public void PushPanel(string panelPath)  
    {  
        if (panelStack.Count > 0)  
        {  
            BasePanel topPanel = panelStack.Peek();  
            topPanel.OnPause();  
        }  
        BasePanel panel = GetPanel(panelPath);  
        panel.OnEnter();  
        panelStack.Push(panel);  
    }  
  
    /// <summary>  
    /// 出棧，移除面板  
    /// </summary>  
    public void PopPanel()  
    {  
        if (panelStack.Count <= 0) return;  
        BasePanel topPanel = panelStack.Pop();  
        topPanel.OnExit();  
        if (panelStack.Count <= 0) return;  
        BasePanel nextPanel = panelStack.Peek();  
        nextPanel.OnResume();  
    }  
}  
 

using UnityEngine;  
using System.Collections;  
  
/// <summary>  
/// Resources資料夾下UI面板的路徑，新增和變動只需更改這裡即可  
/// </summary>  
public class UIPanelPath {  
  
    public const string MAINUIPANEL = "UIPanel/MainUIPanel";  
    public const string MISSIONCHANGEPANEL = "UIPanel/MissionChangePanel";  
}  
 

using UnityEngine;  
using System.Collections;  
  
/// <summary>  
/// 面板基類，每個面板繼承此類，重寫裡面的方法即可  
/// </summary>  
public class BasePanel : MonoBehaviour {  
  
    //每個子類面板都掛CanvasGroup元件，用於控制顯示和隱藏  
    protected CanvasGroup canvasGroup;   
  
    public virtual void Awake()  
    {  
        canvasGroup = GetComponent<CanvasGroup>();  
    }  
  
    /// <summary>  
    /// 面板顯示  
    /// </summary>  
    public virtual void OnEnter()  
    {  
    }  
  
    /// <summary>  
    /// 面板暫停  
    /// </summary>  
    public virtual void OnPause()  
    {  
    }  
  
    /// <summary>  
    /// 面板恢復  
    /// </summary>  
    public virtual void OnResume()  
    {  
    }  
  
    /// <summary>  
    /// 面板關閉  
    /// </summary>  
    public virtual void OnExit()  
    {  
    }  
}  
 

using UnityEngine;  
using System.Collections;  
  
/// <summary>  
///啟動框架  
/// </summary>  
public class FrameworkStart : MonoBehaviour {  
     
    void Start ()  
    {  
        UIManager.Instance.PushPanel(UIPanelPath.MAINUIPANEL);  
    }  
}  

using UnityEngine;  
using System.Collections;  
using UnityEngine.UI;  
  
public class MainUIPanel : BasePanel {  
  
    [SerializeField]  
    private Button missileButton;  
    [SerializeField]  
    private Button satelliteButton;  
    [SerializeField]  
    private Button spaceportButton;  
  
    private void Start()  
    {  
        missileButton.onClick.AddListener(OnClickMissileButton);  
        satelliteButton.onClick.AddListener(OnClickSatelliteButton);  
        spaceportButton.onClick.AddListener(OnClickSpaceportButton);  
    }  
  
    /// <summary>  
    /// 點選導彈按鈕  
    /// </summary>  
    private void OnClickMissileButton()  
    {  
        Debug.Log("導彈");  
    }  
  
    /// <summary>  
    /// 點選衛星按鈕  
    /// </summary>  
    private void OnClickSatelliteButton()  
    {  
        Debug.Log("衛星");  
    }  
  
    /// <summary>  
    /// 點選空間站按鈕  
    /// </summary>  
    private void OnClickSpaceportButton()  
    {  
        UIManager.Instance.PushPanel(UIPanelPath.MISSIONCHANGEPANEL);  
    }  
  
    public override void OnPause()  
    {  
        canvasGroup.alpha = 0;  
    }  
  
    public override void OnResume()  
    {  
        canvasGroup.alpha = 1;  
    }  
}