[AS3]ApplicationDomain自定义Class

最近开发一款flash游戏，由于资源比较多，所以在个别flash中使用了flash的ApplicationDomain 的getDefinition获取Class这种方式来处理。发现由于loader写法不同 ，用loader第一次getDefinition 一切正常，第二次hasDefinition为true但getDefinition会出现TypeError: Error #1034: 强制转换类型失败 这样的错误。实在觉得奇怪。

下面的lib资源文件见附件

lib资源文件里有3个元件（影片剪辑） 分别为Lib1，Lib2，Lib3 ，分别导出类 Lib1，Lib2，Lib3。Lib3元件中有Lib1，Lib2 个一个实例。

用getDefinition方法获取的Class   Lib3  在new 的时候在第三种写法时出现错误

一下代码用FlexBuilder debug

ClassLoader.as

package 
{ 
    import flash.display.Loader; 
    import flash.errors.IllegalOperationError; 
    import flash.events.Event; 
    import flash.events.EventDispatcher; 
    import flash.events.IOErrorEvent; 
    import flash.events.SecurityErrorEvent; 
    import flash.net.URLRequest; 
    import flash.system.ApplicationDomain; 
    import flash.system.LoaderContext; 
 
    public class ClassLoader extends EventDispatcher { 
        public static var CLASS_LOADED:String = "classLoaded"; 
        public static var LOAD_ERROR:String = "loadError"; 
        public var loader:Loader; 
        private var swfLib:String; 
        private var loadedClass:Class; 
        public function ClassLoader() { 
            loader = new Loader(); 
        } 
        public function load(lib:String):void { 
            swfLib = lib; 
            var request:URLRequest = new URLRequest(swfLib); 
            var context:LoaderContext = new LoaderContext(); 
            context.checkPolicyFile=false; 
            context.applicationDomain=ApplicationDomain.currentDomain; 
            //trace(ApplicationDomain.currentDomain==ApplicationDomain.currentDomain); 
            loader.contentLoaderInfo.addEventListener(Event.COMPLETE,completeHandler); 
            loader.contentLoaderInfo.addEventListener(IOErrorEvent.IO_ERROR,ioErrorHandler); 
            loader.contentLoaderInfo.addEventListener(SecurityErrorEvent.SECURITY_ERROR,securityErrorHandler); 
            loader.load(request,context); 
        } 
        private function completeHandler(e:Event):void { 
            loader.contentLoaderInfo.removeEventListener(Event.COMPLETE,completeHandler); 
                loader.contentLoaderInfo.removeEventListener(IOErrorEvent.IO_ERROR,ioErrorHandler); 
                loader.contentLoaderInfo.removeEventListener(SecurityErrorEvent.SECURITY_ERROR,securityErrorHandler); 
                dispatchEvent(new Event(ClassLoader.CLASS_LOADED)); 
        } 
     
        private function ioErrorHandler(e:Event):void { 
            loader.contentLoaderInfo.removeEventListener(Event.COMPLETE,completeHandler); 
                loader.contentLoaderInfo.removeEventListener(IOErrorEvent.IO_ERROR,ioErrorHandler); 
                loader.contentLoaderInfo.removeEventListener(SecurityErrorEvent.SECURITY_ERROR,securityErrorHandler); 
                dispatchEvent(new Event(ClassLoader.LOAD_ERROR)); 
        } 
     
        private function securityErrorHandler(e:Event):void { 
            loader.contentLoaderInfo.removeEventListener(Event.COMPLETE,completeHandler); 
                loader.contentLoaderInfo.removeEventListener(IOErrorEvent.IO_ERROR,ioErrorHandler); 
                loader.contentLoaderInfo.removeEventListener(SecurityErrorEvent.SECURITY_ERROR,securityErrorHandler); 
                dispatchEvent(new Event(ClassLoader.LOAD_ERROR)); 
        } 
        public function hasClass(className:String):Boolean{ 
            return loader.contentLoaderInfo.applicationDomain.hasDefinition(className); 
        } 
        public function getClass(className:String):Class { 
            try { 
                return loader.contentLoaderInfo.applicationDomain.getDefinition(className) as Class; 
            } catch (e:Error) { 
                throw new IllegalOperationError(className + " definition not found in " + swfLib); 
            } 
            return null; 
        } 
    } 
} 

第一种写法： 这种情况一切正常

package { 
    import flash.display.Sprite; 
    import flash.events.Event; 
 
    public class ApplicationDomainExample extends Sprite 
    { 
        private var loader:ClassLoader; 
        private var loader2:ClassLoader; 
                public function ApplicationDomainExample() { 
                    loader = new ClassLoader(); 
                    loader.addEventListener(ClassLoader.CLASS_LOADED,classLoadedHandler); 
                loader.load("http://127.0.0.1/lib.swf"); 
                    loader2 = new ClassLoader(); 
                    loader2.addEventListener(ClassLoader.CLASS_LOADED,classLoadedHandler2); 
                    <span style="color: #ff0000;">/* 两个loader 一起load情况正常  */ 
                    loader2.load("http://127.0.0.1/lib2.swf");</span> 
        } 
        private function classLoadedHandler(e:Event):void { 
            loader.removeEventListener(Event.COMPLETE,classLoadedHandler); 
            getUI(loader); 
            //loader2.load("http://127.0.0.1/lib2.swf");  //load任何swf文件 包括它自己 
            /* 下面情况也正常  */ 
            //loader2.load("lib.swf"); 
        } 
         
        private function classLoadedHandler2(e:Event):void { 
            loader2.removeEventListener(Event.COMPLETE,classLoadedHandler2); 
            getUI(loader); 
        } 
        private function getUI(l:ClassLoader):void{ 
             if(l.hasClass("Lib3")){ 
                var ui:Object=l.getClass("Lib3"); 
                trace(new ui); 
            }  
         } 
    } 
} 

第二种写法： 正常

package { 
    import flash.display.Sprite; 
    import flash.events.Event; 
 
    public class ApplicationDomainExample extends Sprite 
    { 
        private var loader:ClassLoader; 
        private var loader2:ClassLoader; 
                public function ApplicationDomainExample() { 
                    loader = new ClassLoader(); 
                    loader.addEventListener(ClassLoader.CLASS_LOADED,classLoadedHandler); 
                    loader.load("http://127.0.0.1/lib.swf"); 
                    loader2 = new ClassLoader(); 
                loader2.addEventListener(ClassLoader.CLASS_LOADED,classLoadedHandler2); 
                    /* 下面情况正常 */ 
                    //loader2.load("http://127.0.0.1/lib2.swf"); 
        } 
        private function classLoadedHandler(e:Event):void { 
            loader.removeEventListener(Event.COMPLETE,classLoadedHandler); 
            getUI(loader); 
            //loader2.load("http://127.0.0.1/lib2.swf");  //load任何swf文件 包括它自己 
            /* 下面情况也正常  */ 
            <span style="color: #ff0000;">loader2.load("lib.swf");     //这种跟自己是同域所以正常 可以理解</span> 
        } 
         
        private function classLoadedHandler2(e:Event):void { 
            loader2.removeEventListener(Event.COMPLETE,classLoadedHandler2); 
            getUI(loader); 
        } 
        private function getUI(l:ClassLoader):void{ 
             if(l.hasClass("Lib3")){ 
                var ui:Object=l.getClass("Lib3"); 
                trace(new ui); 
            }  
        } 
    } 
} 

第三种写法：报错

package { 
    import flash.display.Sprite; 
    import flash.events.Event; 
 
    public class ApplicationDomainExample extends Sprite 
    { 
        private var loader:ClassLoader; 
        private var loader2:ClassLoader; 
                public function ApplicationDomainExample() { 
                    loader = new ClassLoader(); 
                    loader.addEventListener(ClassLoader.CLASS_LOADED,classLoadedHandler); 
                    loader.load("http://127.0.0.1/lib.swf"); 
                    loader2 = new ClassLoader(); 
                    loader2.addEventListener(ClassLoader.CLASS_LOADED,classLoadedHandler2); 
        } 
        private function classLoadedHandler(e:Event):void { 
            loader.removeEventListener(Event.COMPLETE,classLoadedHandler); 
            getUI(loader); 
            <span style="color: #ff0000;">loader2.load("http://127.0.0.1/lib2.swf");  //load任何swf文件 包括它自己 这样写就报错</span> 
         } 
         
        private function classLoadedHandler2(e:Event):void { 
            loader2.removeEventListener(Event.COMPLETE,classLoadedHandler2); 
            getUI(loader); 
        } 
        private function getUI(l:ClassLoader):void{ 
             if(l.hasClass("Lib3")){ 
                var ui:Object=l.getClass("Lib3"); 
                trace(new ui); 
            }  
        } 
    } 
}