as3项目要调用外部swf里的类有3种方法：

　　1.将外部的swf发布为swc，使用时将swc引用添加到相应的项目中，这应该是最简单的一种引用。不过当项目中的类或组件比较多时就会使项目发布生成的swf文件大小过大;

　　2.通过资源绑定外部的，然后直接通过类名获取。如：[Embed(source="assets/icon/skin.swf",symbol="Btn_Max")],这种方法也会引起swf文件过大;

　　3.通过域来来获取外部swf里的绑定类，这种方法可以在需要用时才去加载相应的swf文件然后再获取所需要的类。

　　下面是根据第三种方法来获取所需要的类：

package com.mobiano.flipbook.pageeditor
{import com.flasht.tui.display.TArrow;import com.mobiano.flipbook.config.FlipBookConfig;import com.tflash.Components.util.SWFLoader;import flash.display.DisplayObject;import flash.errors.IOError;import flash.events.Event;import flash.events.IOErrorEvent;import flash.events.ProgressEvent;import flash.utils.Dictionary;public class PlugInManager{public static var allExternalClass:Object={};//public var loadingQueue:Object={};//public var swfLoader:SWFLoader;public var loadingQueue:Dictionary=new Dictionary();private static var canInstace:Boolean=false;private static var instace:PlugInManager;private var filePrefix:String="./files/pageConfig/";private var fileSuffix:String=".swf";public function PlugInManager(){if(!canInstace){throw new Error("Can't new PlugInManager"); }}public static function getInstace():PlugInManager{if(instace==null){canInstace=true;instace=new PlugInManager();canInstace=false;}return instace;} public function getComponent(target:TAnnoPlugIn,cpName:String,extClassName:String):void{if(cpName==null||cpName.length<1||extClassName==null||extClassName.length<1)return ;if(allExternalClass.hasOwnProperty()){//return allExternalClass[cpName];var swfLoader:SWFLoader=allExternalClass[cpName];var cl:Class=swfLoader.GetClass(extClassName);if(cl!=null){var extObj:IPlugInInterface=createSWFClass(cl);if(extObj!=null){target.extObj=extObj;}}}else{load(target,cpName,extClassName);}//return null;}public function getSwfUrl(cpName):String{if(cpName!=null){return filePrefix+cpName+fileSuffix;}return null;}protected function getURLFrom(url:String):String{return com.mobiano.flipbook.config.FlipBookConfig.getURLForm(url);}private function load(target:TAnnoPlugIn,cpName:String,extClName:String):void{var swfUrl:String=getSwfUrl(cpName);if(swfUrl==null||swfUrl.length<1)return;swfUrl=getURLFrom(swfUrl);var swfLoader:SWFLoader=new SWFLoader(swfUrl);swfLoader.addEventListener(Event.COMPLETE,onComplete);swfLoader.addEventListener(ProgressEvent.PROGRESS,onProgress);swfLoader.addEventListener(IOErrorEvent.IO_ERROR,onIOError);var obj:Object={target:target,compontName:cpName,extClassName:extClName};//loadingQueue[cpName]=obj;loadingQueue[swfLoader]=obj;swfLoader.Load();}private function onComplete(evt:Event):void{trace(evt.currentTarget);if(evt.currentTarget is SWFLoader){var loader:SWFLoader=evt.currentTarget as SWFLoader;if(loader in loadingQueue){var obj:Object=loadingQueue[loader];if(obj["target"]&&obj["compontName"]&&obj["extClassName"]){var cpName:String=obj["compontName"];var extClassName:String=obj["extClassName"];allExternalClass[cpName]=loader;var cl:Class=loader.GetClass(extClassName);var target:TAnnoPlugIn=obj["target"];if(cl!=null){//allExternalClass[cpName]=cl;var extObj:IPlugInInterface=createSWFClass(cl);if(extObj!=null){target.extObj=extObj;}}}//loader.GetClass(//var target:TAnnoPlugIn=loadingQueue[loader];} }}private function createSWFClass(cl:Class):IPlugInInterface{var extObj:IPlugInInterface;try{if(cl!=null){extObj=new cl();}}catch(e:Error){return null;}return extObj;}private function onProgress(evt:ProgressEvent):void{}private function onIOError(evt:IOError):void{throw new Error("Load swf error:"+evt);}}
}

package com.tflash.Components.util
{import flash.display.DisplayObject;import flash.display.Loader;import flash.display.LoaderInfo;import flash.events.Event;import flash.events.EventDispatcher;import flash.events.IEventDispatcher;import flash.events.IOErrorEvent;import flash.events.ProgressEvent;import flash.net.URLRequest;import flash.system.ApplicationDomain;import flash.system.LoaderContext;[Event(name="complete", type="flash.events.Event")][Event(name="progress",type="flash.events.ProgressEvent")][Event(name="io_error",type="flash.events.IOErrorEvent")]public class SWFLoader extends EventDispatcher{private var loader:Loader;private var content:DisplayObject;private var loadComplete:Boolean=false;private var url:String;public function SWFLoader(url:String){this.url=url;}public function Load(url:String=null):void{if(url!=null){this.url=url;}loadComplete=false;if(loader==null){loader=new Loader();}else{loader.unloadAndStop(true);if(loader.contentLoaderInfo.hasEventListener(Event.COMPLETE)){loader.contentLoaderInfo.removeEventListener(Event.COMPLETE,onLoadComplete);}if(loader.contentLoaderInfo.hasEventListener(ProgressEvent.PROGRESS)){loader.contentLoaderInfo.removeEventListener(IOErrorEvent.IO_ERROR,onLoadIOError);}if(loader.contentLoaderInfo.hasEventListener(IOErrorEvent.IO_ERROR)){loader.contentLoaderInfo.removeEventListener(IOErrorEvent.IO_ERROR,onLoadIOError)}}var context:LoaderContext=new LoaderContext();context.applicationDomain=new ApplicationDomain(ApplicationDomain.currentDomain);var request:URLRequest=new URLRequest(this.url);loader.contentLoaderInfo.addEventListener(Event.COMPLETE,onLoadComplete);loader.contentLoaderInfo.addEventListener(ProgressEvent.PROGRESS,onLoadProgress);loader.contentLoaderInfo.addEventListener(IOErrorEvent.IO_ERROR,onLoadIOError);loader.load(request,context);}private function onLoadProgress(evt:ProgressEvent):void{this.dispatchEvent(evt);}private function onLoadComplete(evt:Event):void{evt.currentTarget.removeEventListener(Event.COMPLETE,onLoadComplete);evt.currentTarget.removeEventListener(IOErrorEvent.IO_ERROR,onLoadIOError);evt.currentTarget.removeEventListener(IOErrorEvent.IO_ERROR,onLoadIOError);content=(evt.currentTarget as LoaderInfo).content;loadComplete=true;this.dispatchEvent(new Event(Event.COMPLETE));}private function onLoadIOError(evt:IOErrorEvent):void{evt.currentTarget.removeEventListener(Event.COMPLETE,onLoadComplete);evt.currentTarget.removeEventListener(IOErrorEvent.IO_ERROR,onLoadIOError);evt.currentTarget.removeEventListener(IOErrorEvent.IO_ERROR,onLoadIOError);this.dispatchEvent(evt);}/*** 获取当前ApplicationDomain内的类定义** name类名称，必须包含完整的命名空间,如 Grave.Function.SWFLoader* info加载swf的LoadInfo，不指定则从当前域获取* return获取的类定义，如果不存在返回null*/public function GetClass(name:String):Class{if(loadComplete&&loader!=null){if(loader.contentLoaderInfo.applicationDomain.hasDefinition(name)){return loader.contentLoaderInfo.applicationDomain.getDefinition(name) as Class;}else{return null;}}return null;}public function GetContent():DisplayObject{return content;}public function GetLoader():Loader{return loader;}}
}