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

2024-08-30 07:14:40   221人阅读

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

 
 
 
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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

 
 
 
 
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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。

 
 
 
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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。

  • 本文固定链接: http://www.xuanyusong.com/archives/2165
  • 转载请注明: 雨松MOMO 2013年03月25日 于 雨松MOMO程序研究院 发表

 

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


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