Unity3D研究院之通过C#使用Advanced CSharp Messenger（五十）

Posted 2020-08-25 mimime

http://www.xuanyusong.com/archives/2165

Advanced CSharp Messenger 属于C#事件的一种。 维基百科中由详细的说明http://wiki.unity3d.com/index.php?title=Advanced_CSharp_Messenger 上周的一天刚巧有朋友问到我这一块的知识，那么我研究出来将它贴在博客中，帮助了他也帮助我自己！哇咔咔。

Advanced CSharp Messenger的特点可以将游戏对象做为参数发送。到底Advanced CSharp Messenger有什么用呢？先创建一个立方体对象，然后把Script脚本绑定在这个对象中。脚本中有一个方法叫DoSomething()。写一段简单的代码，通常我们在调用方法的时候需要这样来写。

 

 

 

C#

 

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private Script script; void Awake() { GameObject cube = GameObject.Find("Cube"); script = cube.GetComponent<Script>(); }   void Update() { if(Input.GetMouseButtonDown(0)) { script.DoSomething(); } }

 

代码比较简单，我就不注释了。 原理就是先获取游戏对象，接着获取脚本组件对象，最后通过脚本组件对象去调用对应脚本中的方法，这样的调用方法我们称之为直接调用。

这个例子中我只调用了一个对象的方法，如果说有成千上万个对象，那么这样调用是不是感觉自己的代码非常的丑？因为你需要一个一个的获取对象然后获取脚本组件然后在调用方法。。。。。 （想想都恐怖！！）

下面我们在用Advanced CSharp Messenger来实现事件的调用。按照维基百科中首先把Message.cs 和Callback.cs拷贝在你的工程中。

CallBack.cs

 

 

 

C#

 

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public delegate void Callback(); public delegate void Callback<T>(T arg1); public delegate void Callback<T, U>(T arg1, U arg2); public delegate void Callback<T, U, V>(T arg1, U arg2, V arg3);

 Message.cs

 

 

 

 

C#

 

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/* * Advanced C# messenger by Ilya Suzdalnitski. V1.0 * * Based on Rod Hyde‘s "CSharpMessenger" and Magnus Wolffelt‘s "CSharpMessenger Extended". * * Features: * Prevents a MissingReferenceException because of a reference to a destroyed message handler. * Option to log all messages * Extensive error detection, preventing silent bugs * * Usage examples: 1. Messenger.AddListener<GameObject>("prop collected", PropCollected);    Messenger.Broadcast<GameObject>("prop collected", prop); 2. Messenger.AddListener<float>("speed changed", SpeedChanged);    Messenger.Broadcast<float>("speed changed", 0.5f); * * Messenger cleans up its evenTable automatically upon loading of a new level. * * Don‘t forget that the messages that should survive the cleanup, should be marked with Messenger.MarkAsPermanent(string) * */   //#define LOG_ALL_MESSAGES //#define LOG_ADD_LISTENER //#define LOG_BROADCAST_MESSAGE #define REQUIRE_LISTENER   using System; using System.Collections.Generic; using UnityEngine;   static internal class Messenger { #region Internal variables   //Disable the unused variable warning #pragma warning disable 0414 //Ensures that the MessengerHelper will be created automatically upon start of the game. static private MessengerHelper messengerHelper = ( new GameObject("MessengerHelper") ).AddComponent< MessengerHelper >(); #pragma warning restore 0414   static public Dictionary<string, Delegate> eventTable = new Dictionary<string, Delegate>();   //Message handlers that should never be removed, regardless of calling Cleanup static public List< string > permanentMessages = new List< string > (); #endregion #region Helper methods //Marks a certain message as permanent. static public void MarkAsPermanent(string eventType) { #if LOG_ALL_MESSAGES Debug.Log("Messenger MarkAsPermanent \t\"" + eventType + "\""); #endif   permanentMessages.Add( eventType ); }   static public void Cleanup() { #if LOG_ALL_MESSAGES Debug.Log("MESSENGER Cleanup. Make sure that none of necessary listeners are removed."); #endif   List< string > messagesToRemove = new List<string>();   foreach (KeyValuePair<string, Delegate> pair in eventTable) { bool wasFound = false;   foreach (string message in permanentMessages) { if (pair.Key == message) { wasFound = true; break; } }   if (!wasFound) messagesToRemove.Add( pair.Key ); }   foreach (string message in messagesToRemove) { eventTable.Remove( message ); } }   static public void PrintEventTable() { Debug.Log("\t\t\t=== MESSENGER PrintEventTable ===");   foreach (KeyValuePair<string, Delegate> pair in eventTable) { Debug.Log("\t\t\t" + pair.Key + "\t\t" + pair.Value); }   Debug.Log("\n"); } #endregion   #region Message logging and exception throwing     static public void OnListenerAdding(string eventType, Delegate listenerBeingAdded) { #if LOG_ALL_MESSAGES || LOG_ADD_LISTENER Debug.Log("MESSENGER OnListenerAdding \t\"" + eventType + "\"\t{" + listenerBeingAdded.Target + " -> " + listenerBeingAdded.Method + "}"); #endif           if (!eventTable.ContainsKey(eventType)) {             eventTable.Add(eventType, null );         }           Delegate d = eventTable[eventType];         if (d != null && d.GetType() != listenerBeingAdded.GetType()) {             throw new ListenerException(string.Format("Attempting to add listener with inconsistent signature for event type {0}. Current listeners have type {1} and listener being added has type {2}", eventType, d.GetType().Name, listenerBeingAdded.GetType().Name));         }     }       static public void OnListenerRemoving(string eventType, Delegate listenerBeingRemoved) { #if LOG_ALL_MESSAGES Debug.Log("MESSENGER OnListenerRemoving \t\"" + eventType + "\"\t{" + listenerBeingRemoved.Target + " -> " + listenerBeingRemoved.Method + "}"); #endif           if (eventTable.ContainsKey(eventType)) {             Delegate d = eventTable[eventType];               if (d == null) {                 throw new ListenerException(string.Format("Attempting to remove listener with for event type \"{0}\" but current listener is null.", eventType));             } else if (d.GetType() != listenerBeingRemoved.GetType()) {                 throw new ListenerException(string.Format("Attempting to remove listener with inconsistent signature for event type {0}. Current listeners have type {1} and listener being removed has type {2}", eventType, d.GetType().Name, listenerBeingRemoved.GetType().Name));             }         } else {             throw new ListenerException(string.Format("Attempting to remove listener for type \"{0}\" but Messenger doesn‘t know about this event type.", eventType));         }     }       static public void OnListenerRemoved(string eventType) {         if (eventTable[eventType] == null) {             eventTable.Remove(eventType);         }     }       static public void OnBroadcasting(string eventType) { #if REQUIRE_LISTENER         if (!eventTable.ContainsKey(eventType)) {             throw new BroadcastException(string.Format("Broadcasting message \"{0}\" but no listener found. Try marking the message with Messenger.MarkAsPermanent.", eventType));         } #endif     }       static public BroadcastException CreateBroadcastSignatureException(string eventType) {         return new BroadcastException(string.Format("Broadcasting message \"{0}\" but listeners have a different signature than the broadcaster.", eventType));     }       public class BroadcastException : Exception {         public BroadcastException(string msg)             : base(msg) {         }     }       public class ListenerException : Exception {         public ListenerException(string msg)             : base(msg) {         }     } #endregion   #region AddListener //No parameters     static public void AddListener(string eventType, Callback handler) {         OnListenerAdding(eventType, handler);         eventTable[eventType] = (Callback)eventTable[eventType] + handler;     }   //Single parameter static public void AddListener<T>(string eventType, Callback<T> handler) {         OnListenerAdding(eventType, handler);         eventTable[eventType] = (Callback<T>)eventTable[eventType] + handler;     }   //Two parameters static public void AddListener<T, U>(string eventType, Callback<T, U> handler) {         OnListenerAdding(eventType, handler);         eventTable[eventType] = (Callback<T, U>)eventTable[eventType] + handler;     }   //Three parameters static public void AddListener<T, U, V>(string eventType, Callback<T, U, V> handler) {         OnListenerAdding(eventType, handler);         eventTable[eventType] = (Callback<T, U, V>)eventTable[eventType] + handler;     } #endregion   #region RemoveListener //No parameters     static public void RemoveListener(string eventType, Callback handler) {         OnListenerRemoving(eventType, handler);           eventTable[eventType] = (Callback)eventTable[eventType] - handler;         OnListenerRemoved(eventType);     }   //Single parameter static public void RemoveListener<T>(string eventType, Callback<T> handler) {         OnListenerRemoving(eventType, handler);         eventTable[eventType] = (Callback<T>)eventTable[eventType] - handler;         OnListenerRemoved(eventType);     }   //Two parameters static public void RemoveListener<T, U>(string eventType, Callback<T, U> handler) {         OnListenerRemoving(eventType, handler);         eventTable[eventType] = (Callback<T, U>)eventTable[eventType] - handler;         OnListenerRemoved(eventType);     }   //Three parameters static public void RemoveListener<T, U, V>(string eventType, Callback<T, U, V> handler) {         OnListenerRemoving(eventType, handler);         eventTable[eventType] = (Callback<T, U, V>)eventTable[eventType] - handler;         OnListenerRemoved(eventType);     } #endregion   #region Broadcast //No parameters     static public void Broadcast(string eventType) { #if LOG_ALL_MESSAGES || LOG_BROADCAST_MESSAGE Debug.Log("MESSENGER\t" + System.DateTime.Now.ToString("hh:mm:ss.fff") + "\t\t\tInvoking \t\"" + eventType + "\""); #endif         OnBroadcasting(eventType);           Delegate d;         if (eventTable.TryGetValue(eventType, out d)) {             Callback callback = d as Callback;               if (callback != null) {                 callback();             } else {                 throw CreateBroadcastSignatureException(eventType);             }         }     }   //Single parameter     static public void Broadcast<T>(string eventType, T arg1) { #if LOG_ALL_MESSAGES || LOG_BROADCAST_MESSAGE Debug.Log("MESSENGER\t" + System.DateTime.Now.ToString("hh:mm:ss.fff") + "\t\t\tInvoking \t\"" + eventType + "\""); #endif         OnBroadcasting(eventType);           Delegate d;         if (eventTable.TryGetValue(eventType, out d)) {             Callback<T> callback = d as Callback<T>;               if (callback != null) {                 callback(arg1);             } else {                 throw CreateBroadcastSignatureException(eventType);             }         } }   //Two parameters     static public void Broadcast<T, U>(string eventType, T arg1, U arg2) { #if LOG_ALL_MESSAGES || LOG_BROADCAST_MESSAGE Debug.Log("MESSENGER\t" + System.DateTime.Now.ToString("hh:mm:ss.fff") + "\t\t\tInvoking \t\"" + eventType + "\""); #endif         OnBroadcasting(eventType);           Delegate d;         if (eventTable.TryGetValue(eventType, out d)) {             Callback<T, U> callback = d as Callback<T, U>;               if (callback != null) {                 callback(arg1, arg2);             } else {                 throw CreateBroadcastSignatureException(eventType);             }         }     }   //Three parameters     static public void Broadcast<T, U, V>(string eventType, T arg1, U arg2, V arg3) { #if LOG_ALL_MESSAGES || LOG_BROADCAST_MESSAGE Debug.Log("MESSENGER\t" + System.DateTime.Now.ToString("hh:mm:ss.fff") + "\t\t\tInvoking \t\"" + eventType + "\""); #endif         OnBroadcasting(eventType);           Delegate d;         if (eventTable.TryGetValue(eventType, out d)) {             Callback<T, U, V> callback = d as Callback<T, U, V>;               if (callback != null) {                 callback(arg1, arg2, arg3);             } else {                 throw CreateBroadcastSignatureException(eventType);             }         }     } #endregion }   //This manager will ensure that the messenger‘s eventTable will be cleaned up upon loading of a new level. public sealed class MessengerHelper : MonoBehaviour { void Awake () { DontDestroyOnLoad(gameObject); }   //Clean up eventTable every time a new level loads. public void OnDisable() { Messenger.Cleanup(); } }

 然后就可以开始使用了，Messager.Broadcast()这样就好比我们发送了一条广播。

 

 

 

C#

 

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void Update() { if(Input.GetMouseButtonDown(0)) { Messenger.Broadcast("Send"); } }

 在需要这条广播的类中来接受它，同样是刚刚说的Script类。接受广播的标志是 Messager.AddListener()参数1表示广播的名称，参数2表示广播所调用的方法。

 

 

 

C#

 

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using UnityEngine; using System.Collections;   public class Script : MonoBehaviour {   void Awake() { Messenger.AddListener( "Send", DoSomething ); } public void DoSomething() { Debug.Log("DoSomething"); } }

 这样一来，只要发送名称为”Send”的方法，就可以在别的类中接收它了。

我们在说说如何通过广播来传递参数,这也是那天那个哥们主要问我的问题。（其实是维基百科上写的不是特别特别的清楚，那哥们误解了）在Callback中可以看出参数最多可以是三个，参数的类型是任意类型，也就是说我们不仅能传递 int float bool 还能传递gameObject类型。

如下所示，发送广播的时候传递了两个参数，参数1是一个游戏对象，参数2是一个int数值。

 

 

 

C#

 

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void Update() { if(Input.GetMouseButtonDown(0)) { GameObject cube = GameObject.Find("Cube"); Messenger.Broadcast<GameObject,int>("Send",cube,1980); } }

 然后是接受的地方 参数用<>存在一起。游戏对象也可以完美的传递。

 

 

 

C#

 

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using UnityEngine; using System.Collections;   public class Script : MonoBehaviour {   void Awake() { Messenger.AddListener<GameObject,int>( "Send", DoSomething ); } public void DoSomething(GameObject obj,int i) { Debug.Log("name " + obj.name + " id =" + i); } }

 

如果传递一个参数<T>

两个参数<T,T>

三个参数<T,T,T>   

怎么样使用起来还是挺简单的吧？

我觉得项目中最好不要大量的使用代理事件这类的方法（根据需求而定），虽然可以让你的代码非常的简洁，但是它的效率不高大概比直接调用慢5-倍左右吧，就好比美好的东西一定都有瑕疵一样。 还记得Unity自身也提供了一种发送消息的方法吗？，用过的都知道效率也非常低下，虽然我们看不到它具体实现的源码是如何实现的，但是我觉得原理可能也是这样的。 欢迎和大家一起讨论与学习。

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