Unity-自定义事件派发器的两次尝试

一、前言：

在游戏开发的很多时候，需要引用其他类的方法，但是一旦类多起来了，相互引用会导致引用关系混乱，极其难以阅读。

以前初次做抖音小游戏时，和一位经验老道的cocos程序员合作，看到我写的代码他不禁皱起眉头，说我的引用关系太乱了，看不懂，但是他又不知道unity的事件派发器怎么写，就去网上找了一个。简直惊艳到我了。后来在现在公司做，又见到了一种事件派发器，于是心生感慨，模仿写了一个，并写博客记录一下。

二、现在做的事件派发器

1.声明对应的委托，此委托主要为事件用的。委托的所有返回类型都为Void，简化派发器的复杂程度；明确委托的方法参数类型，有几种类型就定义几种委托。

public delegate void VoidDelegate();public delegate void BoolDelegate(params bool[] parameters);public delegate void NumberDelegate(params float[] parameters);public delegate void GameObjectDelegate(params GameObject[] parameters);

2.存储容器，用于存储事件

private static List<VoidDelegate> GameStart_List;

3.监听者，暴露给外部调用者的接口，对监听者的+=或-=对应容器里的Add和Remove

public static event VoidDelegate GameStart_Listener    {        add        {            if(value != null)            {                if(GameStart_List == null)                {                    GameStart_List = new List<VoidDelegate>(1);                }                GameStart_List.Add(value);            }        }        remove        {            if(value != null)            {                for(int i = 0;i<GameStart_List.Count;i++)                {                    if(GameStart_List[i] != null && GameStart_List[i].Equals(value))                    {                        GameStart_List.RemoveAt(i);                        break;                    }                }            }        }    }

4.派发者，因为event只能在声明类内部Invoke，所以需要暴露给外部调用者接口

public static void GameStart_Dispatch()    {        if(GameStart_List == null || GameStart_List.Count <= 0)        {            return;        }        for(int i = 0;i < GameStart_List.Count;i++)        {            GameStart_List[i]?.Invoke();        }    }

5.上文可看见我的事件叫GameStart,那么我想新增一个GameEnd的事件，岂不是又要写一遍？而且假如我的方法参数是float呢？是bool呢？是GameObject呢？岂不是改动很大？所以我在Unity做了一个自动生成事件的工具

5.1 定义ScriptObject作为配置文件，可随时修改以添加或者删除事件

[CreateAssetMenu]public class EventHandlerSetting:ScriptableObject{    public List<EventType> types;    public List<EventItem> items;}[System.Serializable]public class EventItem{    public string eventName;    public string typeName;}[System.Serializable]public class EventType{    public string typeName;    public string typeDelegate;}

 

 

 5.2 自动生成脚本工具

using System.Collections;using System.Collections.Generic;using UnityEngine;using UnityEditor;using System.IO;using System.Text;using System.Text.RegularExpressions;public class CodeGen{    private static string SettingPath = @"EventHandleSetting";    private static EventHandlerSetting SettingObj;    private static string CodePath = @"Assets\EventHandler\";    private static string CodeName = "EventHandler.cs";    private static string LineFeed = "\r\n";    private static string LineTable = "\t";    [MenuItem("Tools/EventCodeGen")]    public static void CreateEventCode()    {        if (File.Exists(CodePath+CodeName))        {            File.Delete(CodePath + CodeName);        }        File.Create(CodePath + CodeName).Dispose();        LoadSetting();        File.AppendAllText(CodePath + CodeName, CreateNamespace());        File.AppendAllText(CodePath + CodeName, CreateDelegate());        File.AppendAllText(CodePath + CodeName, CreateClass());        AssetDatabase.Refresh();    }    /// <summary>    /// 加载配置文件    /// </summary>    static void LoadSetting()    {        SettingObj = Resources.Load<EventHandlerSetting>(SettingPath);    }    static string CreateNamespace()    {        StringBuilder result = new StringBuilder();        result.Append("using System;" + LineFeed);        result.Append("using System.Collections;" + LineFeed);        result.Append("using System.Collections.Generic;" + LineFeed);        result.Append("using UnityEngine;" + LineFeed+LineFeed);        return result.ToString();    }    /// <summary>    /// 创建委托类型    /// </summary>    /// <returns></returns>    static string CreateDelegate()    {        StringBuilder result = new StringBuilder();        string commnPrefix = "public delegate void ";        using (var e = SettingObj.types.GetEnumerator())        {            while (e.MoveNext())            {                result.Append(commnPrefix + e.Current.typeDelegate + ";" + LineFeed);            }        }        result.Append(LineFeed);        return result.ToString();    }    /// <summary>    /// 创建EventHandler类    /// </summary>    /// <returns></returns>    static string CreateClass()    {        StringBuilder result = new StringBuilder();        result.Append("public class EventHandler"+LineFeed);        result.Append("{"+LineFeed);        List<EventItem> ls = SettingObj.items;        for (int i = 0; i < ls.Count; i++)        {            string eventName = ls[i].eventName;            string eventType = ls[i].typeName;            result.Append(CreateEvent(eventName, eventType));        }        result.Append("}");        return result.ToString();    }    /// <summary>    /// 创建事件派发器    /// </summary>    /// <param name="eventName"></param>    /// <param name="eventType"></param>    /// <returns></returns>    static string CreateEvent(string eventName,string eventType)    {        StringBuilder result = new StringBuilder();        result.Append(LineFeed + "#region " + eventName + LineFeed);        result.Append(MutiLineTable(1) + string.Format("private static List<{0}> {1}_List;", eventType + "Delegate", eventName) + LineFeed);//创建List        result.Append(CreateListener(eventName, eventType));        result.Append(CreateDispatch(eventName, eventType));        result.Append("#endregion"+LineFeed);        return result.ToString();    }    /// <summary>    /// 创建Listener    /// </summary>    /// <param name="eventName"></param>    /// <param name="eventType"></param>    /// <returns></returns>    static string CreateListener(string eventName,string eventType)    {        StringBuilder result = new StringBuilder();        result.Append(MutiLineTable(1) + string.Format("public static event {0} {1}_Listener", eventType + "Delegate", eventName) + LineFeed);        result.Append(MutiLineTable(1) + "{" + LineFeed);        #region add        result.Append(MutiLineTable(2) + "add" + LineFeed);        result.Append(MutiLineTable(2) + "{" + LineFeed);        result.Append(MutiLineTable(3) + "if(value != null)" + LineFeed);        result.Append(MutiLineTable(3) + "{" + LineFeed);        result.Append(MutiLineTable(4) + string.Format("if({0}_List == null)", eventName) + LineFeed);        result.Append(MutiLineTable(4) + "{" + LineFeed);        result.Append(MutiLineTable(5) + string.Format("{0}_List = new List<{1}>(1);", eventName, eventType + "Delegate")+LineFeed);        result.Append(MutiLineTable(4) + "}" + LineFeed);        result.Append(MutiLineTable(4) + string.Format("{0}_List.Add(value);", eventName) + LineFeed);        result.Append(MutiLineTable(3) + "}" + LineFeed);        result.Append(MutiLineTable(2) + "}" + LineFeed);        #endregion        #region remove        result.Append(MutiLineTable(2) + "remove" + LineFeed);        result.Append(MutiLineTable(2) + "{" + LineFeed);        result.Append(MutiLineTable(3) + "if(value != null)" + LineFeed);        result.Append(MutiLineTable(3) + "{" + LineFeed);        result.Append(MutiLineTable(4) + string.Format("for(int i = 0;i<{0}_List.Count;i++)", eventName) + LineFeed);        result.Append(MutiLineTable(4) + "{" + LineFeed);        result.Append(MutiLineTable(5) + string.Format("if({0}_List[i] != null && {1}_List[i].Equals(value))",eventName,eventName) + LineFeed);        result.Append(MutiLineTable(5) + "{" + LineFeed);        result.Append(MutiLineTable(6) + string.Format("{0}_List.RemoveAt(i);" ,eventName) + LineFeed);        result.Append(MutiLineTable(6) + "break;" + LineFeed);        result.Append(MutiLineTable(5) + "}" + LineFeed);        result.Append(MutiLineTable(4) + "}" + LineFeed);        result.Append(MutiLineTable(3) + "}" + LineFeed);        result.Append(MutiLineTable(2) + "}" + LineFeed);        #endregion        result.Append(MutiLineTable(1) + "}" + LineFeed);        return result.ToString();    }    /// <summary>    /// 创建Dispatch    /// </summary>    /// <param name="eventName"></param>    /// <param name="eventType"></param>    /// <returns></returns>    static string CreateDispatch(string eventName,string eventType)    {        StringBuilder result = new StringBuilder();        result.Append(MutiLineTable(1) + string.Format("public static void {0}_Dispatch({1})", eventName, GetTypeParameter(eventType)) + LineFeed);        result.Append(MutiLineTable(1) + "{" + LineFeed);        result.Append(MutiLineTable(2) + string.Format("if({0}_List == null || {1}_List.Count <= 0)", eventName, eventName) + LineFeed);        result.Append(MutiLineTable(2) + "{" + LineFeed);        result.Append(MutiLineTable(3) + "return;" + LineFeed);        result.Append(MutiLineTable(2) + "}" + LineFeed);        result.Append(MutiLineTable(2) + string.Format("for(int i = 0;i < {0}_List.Count;i++)", eventName) + LineFeed);        result.Append(MutiLineTable(2) + "{" + LineFeed);        if (!string.IsNullOrEmpty(GetTypeParameter(eventType)))        {            result.Append(MutiLineTable(3) + string.Format("{0}_List[i]?.Invoke(parameters[i]);", eventName) + LineFeed);        }        else        {            result.Append(MutiLineTable(3) + string.Format("{0}_List[i]?.Invoke();", eventName) + LineFeed);        }        result.Append(MutiLineTable(2) + "}" + LineFeed);        result.Append(MutiLineTable(1) + "}" + LineFeed);        return result.ToString();    }    /// <summary>    /// 获取字符串中括号中的内容    /// </summary>    /// <param name="typeName"></param>    /// <returns></returns>    static string GetTypeParameter(string typeName)    {        if (string.IsNullOrEmpty(typeName))        {            return string.Empty;        }        using (var e=SettingObj.types.GetEnumerator())        {            while (e.MoveNext())            {                if (e.Current.typeName==typeName)                {                    string @delegate = e.Current.typeDelegate;                    string result = @delegate.Substring(@delegate.IndexOf("(") + 1, @delegate.IndexOf(")") - (@delegate.IndexOf("(") + 1));                    Debug.Log(result);                    return result;                }            }        }        return string.Empty;    }    /// <summary>    /// 多个table    /// </summary>    /// <param name="count"></param>    /// <returns></returns>    static string MutiLineTable(int count)    {        StringBuilder result = new StringBuilder();        for (int i = 0; i < count; i++)        {            result.Append(LineTable);        }        return result.ToString() ;    }}

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6.总结

当然，我的这一套事件系统肯定还是有问题的。如果方法参数不止一个float呢？第二个参数是bool？组合起来呢？还有一个问题是，配置文件不够人性化，全部都是字符串，假如多大一个空格或者标点就废了。还有一个非常严重的问题，如果生成的脚本，在语法上有错，不能通过编译器，Unity就会报错，再次点击生成就不会生效。我认识的一个主程让我在Unity外部生成，不要依赖Unity，且使用类似Lua、Python这种脚本语言，目前还不会哈哈哈哈。

三、以前做的事件派发器

1.需要一个通用的参数类型，叫EventArgs,基础类型为Systen.Object

public class EventArgs{    private List<System.Object> parameters;    public int Count    {        get        {            if (parameters!=null)            {                return parameters.Count;            }            else            {                Debug.Log("parameters is not init");                return 0;            }        }    }    public EventArgs(params System.Object[] parameters)    {        if (this.parameters==null)        {            this.parameters = new List<object>();        }        for (int i = 0; i < parameters.Length; i++)        {            this.parameters.Add(parameters[i]);        }    }    public System.Object this[int index]    {        get        {            if (index>=0||index<parameters.Count)            {                return parameters[index];            }            else            {                Debug.LogError("index must be in range of parameters");                return null;            }        }    }}

2.还是那句老话，事件派发器需要容器、监听、派发三部分。

public class EventDispatcher{    public delegate void Listener(EventArgs args);    private static Dictionary<string, Listener> cacheEvents = new Dictionary<string, Listener>();    public static void Attach(string tag,Listener listen)    {        if (cacheEvents==null)        {            cacheEvents = new Dictionary<string, Listener>();        }        if (cacheEvents.ContainsKey(tag))        {            Debug.LogWarning("this tag already exsit in cache,please check agin,tag name:" + tag);            return;        }        if (listen==null)        {            Debug.LogWarning("listen is null,cache failed");            return;        }        cacheEvents.Add(tag, listen);    }    public static void Detach(string tag)    {        if (!cacheEvents.ContainsKey(tag))        {            Debug.LogWarning("tag is not exsit in cache,tag name:"+tag);            return;        }        cacheEvents.Remove(tag);    }    public static void Dispatch(string tag,EventArgs args)    {        if (!cacheEvents.ContainsKey(tag))        {            Debug.LogWarning("this tag does not exsit in cache,please check agin,tag name:" + tag);            return;        }        if (cacheEvents[tag]==null)        {            Debug.LogWarning("this listen is null,invoke failed");            return;        }        cacheEvents[tag].Invoke(args);    }}

3.总结：

此事件派发器也存在缺陷，任何方法的参数类型都会被转换成System.Object类型，有多余的封装箱操作。且不能重复添加一个方法，至少他的tag不能一样。代码可读性差，报错了都不知道在哪儿。

四、关于事件派发器自己的看法

我相信没有完美的派发器这一说，好的派发器与坏的派发器区别在于，调用是否方便？会不会存在隐藏的危险bug？性能上如何？不同项目有不同的事件派发器，适合自己的才是最好的。如果强行将事件派发器做成那种万金油工具，且不论他是否真的是万金油，代码开发成本之大，耗费时间之长，也不是一般小游戏公司能够耗得起的。上文所述两个派发器，实际上都可以用，而且经历过实战的，并没有什么大问题。