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。
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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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