在設計五中，我們把事件系統EventSystem實現一下。這個EventSystem類主要實現的是事件的註冊，觸發，以及分發Event消息的作用。提供接口對外使用的。在這裏面爲了功能擴展方便用了好多模板函數，方便大家調用。
分發消息的時候，我們採用的是隊列的方式，就是先進先出原則。
首先要把消息事件註冊一下，就是將其放到我們預先定義的表裏面。函數代碼如下所示：
int Register(string eventName, Func<object,object,object,bool> action) {
int listenID = ++mNextListenID;
Listen listen = (mFreeListen.Count == 0) ? new Listen() : mFreeListen.Pop();
listen.mID = listenID;
listen.mAction = action;
mRegistered.Add(listenID, listen);
List<int> eventList;
if(!mRegisteredEvents.TryGetValue(eventName, out eventList))
eventList = mRegisteredEvents[eventName] = new List<int>();
eventList.Add(listenID);
return listenID;
}接下來就是 消息事件的觸發代碼如下：
public void Trigger(string eventName) {
Call(eventName, null, null, null);
}void Call(string eventName, object arg1, object arg2, object arg3) {
List<int> listenerList;
if(mRegisteredEvents.TryGetValue(eventName, out listenerList)) {
for(int i = listenerList.Count - 1; i >= 0; --i) {
Listen listener;
if(mRegistered.TryGetValue(listenerList[i], out listener)) {
if(!listener.mAction(arg1, arg2, arg3)) {
mRegistered.Remove(listenerList[i]);
mFreeListen.Push(listener);
listenerList.RemoveAt(i);
}
}
else {
listenerList.RemoveAt(i);
}
}
if(listenerList.Count == 0) {
mRegisteredEvents.Remove(eventName);
}
}
}遍歷查找消息列表是否在mRegistererdEvents這個字典裏面，mRegisteredEvents的定義如下：
Dictionary<string,List<int>> mRegisteredEvents = new Dictionary<string, List<int>>();
Listen的定義如下：
class Listen {
public int mID;
public Func<object,object,object,bool> mAction;
}接下來就是最核心的功能了，狀態機的切換功能代碼：
public int On<T1,T2,T3>(string eventName, Func<T1,T2,T3,bool> action) {
return Register(eventName, delegate(object arg1, object arg2, object arg3) {
T1 param1;
T2 param2;
T3 param3;
try { param1 = (T1)arg1; } catch { param1 = default(T1); }
try { param2 = (T2)arg2; } catch { param2 = default(T2); }
try { param3 = (T3)arg3; } catch { param3 = default(T3); }
return(action(param1, param2, param3));
});
}
public int On<T1,T2,T3>(string eventName, Action<T1,T2,T3> action) {
return Register(eventName, delegate(object arg1, object arg2, object arg3) {
T1 param1;
T2 param2;
T3 param3;
try { param1 = (T1)arg1; } catch { param1 = default(T1); }
try { param2 = (T2)arg2; } catch { param2 = default(T2); }
try { param3 = (T3)arg3; } catch { param3 = default(T3); }
action(param1, param2, param3);
return true;
});
}整個的EventSystem事件系統的代碼如下所示：
using System;
using System.Collections;
using System.Collections.Generic;
namespace EventSystem {
public class Dispatcher {
public void Trigger(string eventName) {
Call(eventName, null, null, null);
}
public void Dispatch(string eventName) {
Dispatched d = (mFreeDispatch.Count == 0) ? new Dispatched() : mFreeDispatch.Pop();
mDispatched.Enqueue(d.Set(eventName));
}
public int On(string eventName, Func<bool> action) {
return Register(eventName, delegate(object arg1, object arg2, object arg3) {
return(action());
});
}
public int On(string eventName, Action action) {
return Register(eventName, delegate(object arg1, object arg2, object arg3) {
action();
return(true);
});
}
public void Trigger(string eventName, object param1) {
Call(eventName, param1, null, null);
}
public void Dispatch(string eventName, object param1) {
Dispatched d = (mFreeDispatch.Count == 0) ? new Dispatched() : mFreeDispatch.Pop();
mDispatched.Enqueue(d.Set(eventName, param1));
}
public int On<T>(string eventName, Func<T,bool> action) {
return Register(eventName, delegate(object arg1, object arg2, object arg3) {
T param1;
try { param1 = (T)arg1; } catch { param1 = default(T); }
return(action(param1));
});
}
public int On<T>(string eventName, Action<T> action) {
return Register(eventName, delegate(object arg1, object arg2, object arg3) {
T param1;
try { param1 = (T)arg1; } catch { param1 = default(T); }
action(param1);
return true;
});
}
public void Trigger(string eventName, object param1, object param2) {
Call(eventName, param1, param2, null);
}
public void Dispatch(string eventName, object param1, object param2) {
Dispatched d = (mFreeDispatch.Count == 0) ? new Dispatched() : mFreeDispatch.Pop();
mDispatched.Enqueue(d.Set(eventName, param1, param2));
}
public int On<T1,T2>(string eventName, Func<T1,T2,bool> action) {
return Register(eventName, delegate(object arg1, object arg2, object arg3) {
T1 param1;
T2 param2;
try { param1 = (T1)arg1; } catch { param1 = default(T1); }
try { param2 = (T2)arg2; } catch { param2 = default(T2); }
return(action(param1, param2));
});
}
public int On<T1,T2>(string eventName, Action<T1,T2> action) {
return Register(eventName, delegate(object arg1, object arg2, object arg3) {
T1 param1;
T2 param2;
try { param1 = (T1)arg1; } catch { param1 = default(T1); }
try { param2 = (T2)arg2; } catch { param2 = default(T2); }
action(param1, param2);
return true;
});
}
public void Trigger(string eventName, object param1, object param2, object param3) {
Call(eventName, param1, param2, param3);
}
public void Dispatch(string eventName, object param1, object param2, object param3){
Dispatched d = (mFreeDispatch.Count == 0) ? new Dispatched() : mFreeDispatch.Pop();
mDispatched.Enqueue(d.Set(eventName, param1, param2, param3));
}
public int On<T1,T2,T3>(string eventName, Func<T1,T2,T3,bool> action) {
return Register(eventName, delegate(object arg1, object arg2, object arg3) {
T1 param1;
T2 param2;
T3 param3;
try { param1 = (T1)arg1; } catch { param1 = default(T1); }
try { param2 = (T2)arg2; } catch { param2 = default(T2); }
try { param3 = (T3)arg3; } catch { param3 = default(T3); }
return(action(param1, param2, param3));
});
}
public int On<T1,T2,T3>(string eventName, Action<T1,T2,T3> action) {
return Register(eventName, delegate(object arg1, object arg2, object arg3) {
T1 param1;
T2 param2;
T3 param3;
try { param1 = (T1)arg1; } catch { param1 = default(T1); }
try { param2 = (T2)arg2; } catch { param2 = default(T2); }
try { param3 = (T3)arg3; } catch { param3 = default(T3); }
action(param1, param2, param3);
return true;
});
}
public bool Cancel(int listenerID) {
return mRegistered.Remove(listenerID);
}
public void DispatchPending() {
while(mDispatched.Count > 0) {
Dispatched d = mDispatched.Dequeue();
Call(d.mEventName, d.mArg1, d.mArg2, d.mArg3);
mFreeDispatch.Push(d);
}
}
int Register(string eventName, Func<object,object,object,bool> action) {
int listenID = ++mNextListenID;
Listen listen = (mFreeListen.Count == 0) ? new Listen() : mFreeListen.Pop();
listen.mID = listenID;
listen.mAction = action;
mRegistered.Add(listenID, listen);
List<int> eventList;
if(!mRegisteredEvents.TryGetValue(eventName, out eventList))
eventList = mRegisteredEvents[eventName] = new List<int>();
eventList.Add(listenID);
return listenID;
}
void Call(string eventName, object arg1, object arg2, object arg3) {
List<int> listenerList;
if(mRegisteredEvents.TryGetValue(eventName, out listenerList)) {
for(int i = listenerList.Count - 1; i >= 0; --i) {
Listen listener;
if(mRegistered.TryGetValue(listenerList[i], out listener)) {
if(!listener.mAction(arg1, arg2, arg3)) {
mRegistered.Remove(listenerList[i]);
mFreeListen.Push(listener);
listenerList.RemoveAt(i);
}
}
else {
listenerList.RemoveAt(i);
}
}
if(listenerList.Count == 0) {
mRegisteredEvents.Remove(eventName);
}
}
}
class Listen {
public int mID;
public Func<object,object,object,bool> mAction;
}
class Dispatched {
public Dispatched Set(string eventName, object arg1=null, object arg2=null, object arg3=null) {
mEventName = eventName;
mArg1 = arg1;
mArg2 = arg2;
mArg3 = arg3;
return this;
}
public string mEventName;
public object mArg1, mArg2, mArg3;
}
Dictionary<string,List<int>> mRegisteredEvents = new Dictionary<string, List<int>>();
Dictionary<int,Listen> mRegistered = new Dictionary<int, Listen>();
Stack<Listen> mFreeListen = new Stack<Listen>();
Stack<Dispatched> mFreeDispatch = new Stack<Dispatched>();
Queue<Dispatched> mDispatched = new Queue<Dispatched>();
int mNextListenID = 4711;
}
}接下來我會在最後一講也就是設計六中，給大家說一下如何去使用。