AS3嵌入swf元件库，如何访问指定的资源

发布时间：2020-12-15 18:09:12 所属栏目：百科来源：网络整理

导读：It’s been a long-time without a post. Part of the reason for that has been starting work at a new job (which involves a commute),and part has been that as part of my new job,I was actually encouraged to spend time playing World of Warcraf

It’s been a long-time without a post. Part of the reason for that has been starting work at a new job (which involves a commute),and part has been that as part of my new job,I was actually encouraged to spend time playing World of Warcraft. To me,that’s like taking a crowbar to Pandora’s Box and having a peek inside. I learned quite a lot,but have also played just a few too many Warsong Gulches.

Back to work,and I was doing a little prototyping this evening,when I came across a familiar problem: In AS3 we can use

 
        [Embed(source= 
        "asset.swf" 
        ,symbol= 
        "symbol" 
        )] 
       
        private 
         var 
        symbolClass:Class; 
       
        var 
         symbol:MovieClip =  
        new 
         symbolClass();

to embed a symbol from an art SWF in what is probably a code-built SWF. That’s great,but what if you want to embed an entire SWF?

 
        [Embed(source= 
        "asset.swf" 
        )] 
       
        private 
         var 
        assetClass:Class; 
       
        var 
         asset:MovieClip =  
        new 
         assetClass();

looks like it should do the trick,but you can’t access any of the information within the asset. That’s a real pain,the reason for which is pretty convoluted. I remembered working around this problem in the past,and happily managed to unearth a long-forgotten treasure in my codebase,which I thought I’d share (having rapidly refactored it to use as3-signals,naturally).

 
        package 
         com.alecmce.util 
       
        { 
       
        ???  
        import 
        org.osflash.signals.Signal; 
       
        ???  
        import 
        mx.core.MovieClipAsset; 
       
        ???  
        import 
        flash.display.Loader; 
       
        ???  
        import 
        flash.display.LoaderInfo; 
       
        ???  
        import 
        flash.display.MovieClip; 
       
        ???  
        import 
        flash.events.Event; 
       
        ???  
        public 
        class 
        UnpackEmbed 
       
        ???  
        { 
       
        ???????  
        private 
        var 
        _ready:Signal; 
       
        ???????  
        private 
        var 
        _asset:MovieClipAsset; 
       
        ???????  
        private 
        var 
        _content:MovieClip; 
       
        ???????  
        public 
        function 
        UnpackEmbed(assetClass:Class) 
       
        ???????  
        { 
       
        ???????????  
        _asset =  
        new 
         assetClass(); 
       
        ???????????  
        _ready =  
        new 
         Signal(UnpackEmbed); 
       
        ???????????  
        var 
        loader:Loader = Loader(_asset.getChildAt( 
        0 
        )); 
       
        ???????????  
        var 
        info:LoaderInfo = loader.contentLoaderInfo; 
       
        ???????????  
        info.addEventListener(Event.COMPLETE,onLoadComplete); 
       
        ???????  
        } 
       
        ???????  
        private 
        function 
        onLoadComplete(event:Event): 
        void 
       
        ???????  
        { 
       
        ???????????  
        var 
        info:LoaderInfo = LoaderInfo(event.target); 
       
        ???????????  
        info.removeEventListener(Event.COMPLETE,onLoadComplete); 
       
        ???????????  
        _content = MovieClip(info.loader.content); 
       
        ???????????  
        _ready.dispatch( 
        this 
        ); 
       
        ???????  
        } 
       
        ???????  
        public 
        function 
        get 
         content():MovieClip 
       
        ???????  
        { 
       
        ???????????  
        return 
        _content; 
       
        ???????  
        } 
       
        ???????  
        public 
        function 
        get 
         ready():Signal 
       
        ???????  
        { 
       
        ???????????  
        return 
        _ready; 
       
        ???????  
        } 
       
        ???????  
        public 
        function 
        get 
         asset():MovieClipAsset 
       
        ???????  
        { 
       
        ???????????  
        return 
        _asset; 
       
        ???????  
        } 
       
        ???  
        } 
       
        }

When you embed a SWF in this way then instantiate it,Flash somehow conspires to create a MovieClipAsset with a Loader inside,which will be ‘loading’ the already-embedded content. The content is not available immediately (it may be sometimes,I have encountered cases where it was not),so you have to wait for an Event.COMPLETE to be fired before you can access it. This class exposes a signal that informs you when the content is ready. It could probably be more rigorous,such as including an isComplete flag,but it serves my purposes,when used in the following manner:

 
        [Embed(source= 
        "asset.swf" 
        )] 
       
        private 
         var 
        assetClass:Class; 
       
        asset =  
        new 
        UnpackEmbed(assetClass); 
       
        asset.ready.addOnce(onAssetReady); 
       
        private 
         function 
        onAssetReady(asset:UnpackEmbed): 
        void 
       
        { 
       
        ???  
        // now we can access the asset.content! 
       
        }

   转自： 
  http://alecmce.com/as3/embed-asset-gotcha 
 

   参考： 
  https://github.com/login?return_to=%2Frobertpenner%2Fas3-signals 
 

（编辑：李大同）

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