Unity之UI管理器

这月要开始备战期末考试了，尤其是系统解剖，因此没太多时间学习Unity，本次记录UI管理器。

思路记录

首先需要想，我们如何去做UI管理器？根据我对“面向对象编程”的思考，我们需要找到不同的UI的共同点——它们都有一个ShowPanel(显示面板)和HidePanel(隐藏面板)的方法，这是共同性;它们的差异性在于不同UI逻辑不同，那就用抽象方法，根据具体差异书写不同逻辑。
其次，UI管理器只能有一个，那就想到了单例模式。我们把不同UI做成预设体存在Resources文件夹，通过单例模式+泛型实现显示面板、隐藏面板的方法：ShowPanel,ShowPanel,这样就很方便。 于是我们需要写两个基础的脚本，第一个是BasePanel，所有UI面板的基类,并声明为抽象类：

using Unity.VisualScripting;
using UnityEngine;
using UnityEngine.Events;

public abstract class BasePanel : MonoBehaviour
{
    //声明组件用于全体管理
    private CanvasGroup canvasGroup;
    //淡入淡出速度
    public float alphaSpeed = 10f;
    private bool isShow = false;
    //面板隐藏后要做的事情
    private UnityAction hideCallBack = null;

    private void Awake()
    {
        canvasGroup = GetComponent<CanvasGroup>();
        if (canvasGroup == null)
            canvasGroup = this.AddComponent<CanvasGroup>();
    }
    protected virtual void Start()
    {
        Init();
    }

    //不同的UI有不同的逻辑，写在Init方法里
    protected abstract void Init();

    public virtual void Showme()
    {
        canvasGroup.alpha = 0f;
        isShow = true;
    }

    public virtual void HideMe(UnityAction callback)
    {
        canvasGroup.alpha = 1.0f;
        isShow = false;
        hideCallBack = callback;
    }
    // Update is called once per frame
    void Update()
    {
        if (isShow && canvasGroup.alpha != 1f)
        {
            canvasGroup.alpha += Time.deltaTime * alphaSpeed;
            if (canvasGroup.alpha == 1f)
                canvasGroup.alpha = 1f;
        }
        else if (!isShow && canvasGroup.alpha != 0f)
        {
            canvasGroup.alpha -= Time.deltaTime * alphaSpeed;
            if (canvasGroup.alpha == 0f)
            {
                canvasGroup.alpha = 0f;
                hideCallBack?.Invoke();
            }

        }
    }
}

之后再来写UI管理器具体的逻辑：

using System.Collections.Generic;
using Unity.VisualScripting.FullSerializer;
using UnityEngine;

public class UIManager
{
    public static UIManager instance = new UIManager();
    public static UIManager Instance => instance;
    private Transform canvasTrans;

    //字典存储
    private Dictionary<string,BasePanel> panelDic = new Dictionary<string,BasePanel>();
    //显示面板
    public T ShowPanel<T>() where T : BasePanel
    {
        //获取面板名称
        string panelName = typeof(T).Name;
        //检测是不是有了
        if(panelDic.ContainsKey(panelName) )
            return panelDic[panelName] as T;
        //如果没有我们就实例化一个UI
        GameObject panelObj = GameObject.Instantiate(Resources.Load<GameObject>("UI" + panelName));
        //把这个对象放到场景Canvas下边
        panelObj.transform.SetParent(canvasTrans, false);
        //获取这个UI上的脚本
        T panel = panelObj.GetComponent<T>();
        //把这个脚本存在字典里
        panelDic.Add(panelName, panel);
        panel.Showme();
        return panel;
    }
    //UIManager的构造函数
    public UIManager()
    {
        //得到场景的Canvas对象
        GameObject canvas = GameObject.Instantiate(Resources.Load<GameObject>("UI/Canvas"));
        canvasTrans = canvas.transform;
        GameObject.DontDestroyOnLoad(canvas);
    }

    //隐藏面板,isFade用来控制你想不想实现UI淡入淡出效果
    public void HidePanel<T>(bool isFade = true)where T : BasePanel
    {
        string panelName = typeof(T).Name;
        if(panelDic.ContainsKey(panelName) )
        {
            if(isFade)
            {
                panelDic[panelName].HideMe(() =>
                {
                    GameObject.Destroy(panelDic[panelName].gameObject);
                    panelDic.Remove(panelName);
                });
            }
            else
            {
                //删除UI
                GameObject.Destroy(panelDic[panelName].gameObject);
                panelDic.Remove(panelName);
            }
        }
    }

    public T GetPanel<T>() where T: BasePanel
    {
        string panelName = typeof(T).Name;
        if(panelDic.ContainsKey(panelName) )
            return panelDic[panelName] as T;
        return null;
    }
}