下一个更精彩：AS2.0中实现数据结构-哈希表实现

Event Bubbling (事件浮升机制)

ok,我姑且这么称呼Event Bubbling吧.原来Ralf在自己的Blog上发表了在As2.0中使用Event Bubbling的方法.实在是个有创意的想法.

Event Bubbling原本是只能在AS3.0中使用的.在Event Bubbling机制里面，产生事件的对象首先会收到事件。然后，事件会依照对象的等级结构向上传播.那么简单的说在Flash中的使用Event Bubbling则是使处理嵌套的MC显得简单很多.Event Bubbling的使用主要便是很好的加强了事件处理的连续性.

Ralf的方案是用自己的方法来替换dispatch的方法,下面这段方法是Ralf的一个范例,你也可以自己修改:

public static initializeBubbling(dispatcher:MovieClip){

var parentDispatcher = dispatcher._parent; //add traversal optionally, see comments below

var oldDispatchEvent = dispatcher.dispatchEvent;

dispatcher.dispatchEvent = function( evt){

oldDispatchEvent.call( dispatcher, evt);

if( evt.bubbles){

parentDispatcher.dispatchEvent( evt);

}

}

}

更详细的文章,我想还是看原文比较好

同时,Peter Elst也写了一个使用的范例.

比如,当你不使用Event Bubbling时,你需要通过以下的方法来让mc1.mc2广播事件.

mc1.mc2.addEventListener("someEvent",someEventHandler);

如果使用Event Bubbling则可以这样.

mc1.addEventListener("someEvent",someEventHandler);

由于这样的事件链机制,你就不用担心时间出自哪里了.

import mx.events.EventDispatcher;

// Ralf Bokelberg’s AS2.0 event bubbling workaround

initializeBubbling = function(dispatcher:MovieClip) {

var parentDispatcher = dispatcher._parent;

var oldDispatchEvent = dispatcher.dispatchEvent;

dispatcher.dispatchEvent = function( evt){

oldDispatchEvent.call( dispatcher, evt);

if( evt.bubbles){

parentDispatcher.dispatchEvent(evt);

}

}

}

// create empty movieclips

var mc1:MovieClip = createEmptyMovieClip("mc1",1);

var mc2:MovieClip = mc1.createEmptyMovieClip("mc2",1);

// initialize EventDispatcher

EventDispatcher.initialize(mc1);

EventDispatcher.initialize(mc1.mc2);

// initialize event bubbling

initializeBubbling(mc1.mc2);

// add event listeners to movieclips

mc1.mc2.addEventListener("customEvent",function() {

trace("customEvent captured by mc1.mc2");

});

mc1.addEventListener("customEvent",function() {

trace("customEvent captured by mc1");

});

// dispatch event

mc1.mc2.dispatchEvent({type:"customEvent",bubbles:true});

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