本人一直认为AS3的事件处理机制很是给力 , 今天鼓捣了出来并完美得通过了测试。在AS3中使用函数addEventListener添加事件侦听,用removeEventListener移除事件侦听。着用封装的一个类库可以彻底地终结消息传递中无规则,无规律的混乱状态,从而达到代码逻辑清晰性。改起来也相当简单(做过程序员的都懂)。
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关于此类库的实现原理 , 其实使用的是委托(delegate),让侦听函数(观察者)挂载到此委托上,当然消息有不同的类型,如windows系统中有单击,双击,右击等不同的事件类型,在这个类库里面都有实现。
首先,需要指出:
IEventType ( 所有事件类型的接口 )
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace MsgEventLib.com { public interface IEventType { ////// 类的类型 /// Type EventMainType { get; } String GetEventTypeName(string type); } }
思想:事件类型以 类的Type.Name + "_" + 事件名称 。 以GetEventTypeName方法实现。
传递的消息体:
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace MsgEventLib.com { public class BaseEvent { public BaseEvent(string eventType, object sender, object msg) { this.eventType = eventType; this.sender = sender; this.msg = msg; } private string @eventType; public string EventType { set { this.eventType = value; } get { return this.eventType; } } private object @sender; public Object Sender { set { this.sender = value; } get { return this.sender; } } private object @msg; public object Msg { set { this.msg = value; } get { return this.msg; } } } }
其中:eventType为事件类型名称 GetEventTypeName , Sender为发送者 , Msg为消息体
事件侦听管理器的实现
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace MsgEventLib.com { public sealed class EventListener : IEventListener { private static IEventListener @instance; public static IEventListener Instance { get { if (instance == null) instance = new EventListener(); return instance; } } private Dictionary@listeners; private EventListener() { @listeners = new Dictionary (); } public void AddEventListener(string type, DeListener myListener) { if (!@listeners.ContainsKey(type)) @listeners.Add(type, myListener); else @listeners[type] += myListener; } public void RemoveEventListener(string type, DeListener myListener) { if (@listeners.ContainsKey(type)) { @listeners[type] -= myListener; if (@listeners[type] == null) @listeners.Remove(type); } } public void RemoveAllEventListener() { if (@listeners != null && @listeners.Count > 0) { List keys = new List (@listeners.Keys);//获得所有的键值 for (int j = 0; j < keys.Count; j++) { if (@listeners[keys[j]] != null) { Delegate[] des = @listeners[keys[j]].GetInvocationList(); if (des != null && des.Length > 0) { for (int i = 0; i < des.Length; i++) { @listeners[keys[j]] -= des[i] as DeListener; } } } @listeners.Remove(keys[j]); } } } public DeListener GetDeListenerByType(string type) { if (@listeners != null && @listeners.ContainsKey(type)) { return @listeners[type]; } return null; } public void Destory() { this.RemoveAllEventListener(); if (@instance != null) @instance = null; } } }
值得注意的是 , 字典 : key为事件类型(GetEventTypeName) , value为委托(可能有多个挂载/观察者)
关于事件发送者(主题)
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace MsgEventLib.com { public sealed class EventDispacterManager : IEventDispacterManager { private static IEventDispacterManager @instance; public static IEventDispacterManager Instance { get { if (instance == null) instance = new EventDispacterManager(); return instance; } } public void Dispatch(string type , BaseEvent @myevent) { DeListener target = EventListener.Instance.GetDeListenerByType(type); if (target != null) { target(@myevent); } } } }
测试的结果
1 , 事件类型
using System; using System.Collections.Generic; using System.Linq; using System.Text; using MsgEventLib.com; namespace TestA.com { public class MyEventType : IEventType { private static MyEventType @instance; public static MyEventType Instance { get { if (@instance == null) @instance = new MyEventType(); return @instance; } } public Type EventMainType { get { return typeof(MyEventType); } } public string GetEventTypeName(string type) { return this.EventMainType.Name + "_" + type; } public static string CLOSE_WINDOWS = "CLOSE_WINDOWS"; public static string OTHRT_TYPE = "OTHRT_TYPE"; } }
2 , 3个类(侦听着)
①:
using System; using System.Collections.Generic; using System.Linq; using System.Text; using MsgEventLib.com; namespace TestA.com { public sealed class Listeners { public Listeners() { string type = MyEventType.Instance.GetEventTypeName(MyEventType.CLOSE_WINDOWS); EventListener.Instance.AddEventListener(type, this.Li); } private void Li(BaseEvent e) { Console.WriteLine("Listeners 触发了Event {0} ", e.Msg); } } }
②:
using MsgEventLib.com; using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TestA.com { public sealed class Lis2 { public Lis2() { string type = MyEventType.Instance.GetEventTypeName(MyEventType.CLOSE_WINDOWS); EventListener.Instance.AddEventListener(type, this.Li); } private void Li(BaseEvent e) { Console.WriteLine("Lis2 触发了Event {0} ", e.Msg); } public void RemoveLis() { string type = MyEventType.Instance.GetEventTypeName(MyEventType.CLOSE_WINDOWS); EventListener.Instance.RemoveEventListener(type, this.Li); Console.WriteLine("Lis2 移除了事件侦听!"); } } }
③:
using MsgEventLib.com; using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TestA.com { public sealed class Lis3 { public Lis3() { string type = MyEventType.Instance.GetEventTypeName(MyEventType.OTHRT_TYPE); EventListener.Instance.AddEventListener(type, this.Li); } private void Li(BaseEvent e) { Console.WriteLine("Lis3 触发了Event {0} ", e.Msg); } } }
事件发送者
using System; using System.Collections.Generic; using System.Linq; using System.Text; using MsgEventLib.com; namespace TestA.com { public sealed class Dispatch { public void Dis() { string type = MyEventType.Instance.GetEventTypeName(MyEventType.CLOSE_WINDOWS); EventDispacterManager.Instance.Dispatch(type, new BaseEvent(type, this, "Event_关闭你的窗口")); } } }
测试:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using TestA.com;
namespace TestA
{
public class Program
{
static void Main(string[] args)
{
Dispatch di = new Dispatch();
Listeners li = new Listeners();
Lis2 li2 = new Lis2();
Lis3 li3 = new Lis3();
di.Dis();
li2.RemoveLis();
di.Dis();
Console.Read();
}
}
}
结果:
因为Lis3侦听的不是事件CLOSE_WINDOWS , 既不会触发 。 因为Lis2移除了事件,所以第二次不会触发。
这只是部分大码。详细请见附件。