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 = @"AssetsEventHandler";     private static string CodeName = "EventHandler.cs";     private static string LineFeed = "rn";     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() ;     } }

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。