Actionscript 3 AS3公共变量赢得'；t存储值

第一次在这里张贴海报

因此，我正在构建一个“多RSS提要阅读器”，并将其分为两类，一类是“TechFeed.as”，另一类是“feed.as”；技术提要通过将URL传递给新的提要对象来实例化多个提要

我目前的问题是，在Feed.as中，我有两个公共变量，它们在TechFeed.as中使用，用于显示有关Feed的基本细节，但是，这些变量拒绝保留我在Feed.as的函数中给它们的任何值，并显示为“null”

编辑：也可能是需要注意的东西；TechFeed.as是stage使用的主要as文件

TechFeed.as

package  {

    import flash.display.MovieClip;

    public class TechFeed extends MovieClip {

        private var feed_one:Feed = new Feed("http://feeds.feedburner.com/crunchgear");
        private var feed_two:Feed = new Feed("http://feeds.mashable.com/Mashable");
        private var feed_three:Feed = new Feed("http://www.engadget.com/rss.xml");

        public function TechFeed() {
            trace(feed_one.feed_title);

            //feed_name.text = feed_one.getFeedTitle();
        }

    }

}

package  {

    import flash.net.URLLoader;
    import flash.events.Event;
    import flash.net.URLRequest;

    public class Feed {

        //Public variables to display feed info
        public var feed_title:XMLList;
        public var feed_desc:String;
        public var feed_link:String;

        //Setting up variables which help load the feeds

        private var feedXML:XML;
        //Create a loader to load an external URL
        private var loader:URLLoader = new URLLoader();


        public function Feed(inURL:String = "") {
            //Load the xml document
            loader.load(new URLRequest(inURL));
            loader.addEventListener(Event.COMPLETE,onLoaded);
        }

        //When the loader had loaded the xml document, pass that into a variable for use. 
        private function onLoaded(e:Event):void {
            feedXML = new XML(e.target.data);

            // break down the xml document elements into singular XML array lists

            //Feed details
            this.feed_title = feedXML.channel.title;
            this.feed_link = feedXML.channel.link;
            this.feed_desc = feedXML.channel.description;

            trace(this.feed_title);

        }

    }

}

Feed.as

package  {

    import flash.display.MovieClip;

    public class TechFeed extends MovieClip {

        private var feed_one:Feed = new Feed("http://feeds.feedburner.com/crunchgear");
        private var feed_two:Feed = new Feed("http://feeds.mashable.com/Mashable");
        private var feed_three:Feed = new Feed("http://www.engadget.com/rss.xml");

        public function TechFeed() {
            trace(feed_one.feed_title);

            //feed_name.text = feed_one.getFeedTitle();
        }

    }

}

package  {

    import flash.net.URLLoader;
    import flash.events.Event;
    import flash.net.URLRequest;

    public class Feed {

        //Public variables to display feed info
        public var feed_title:XMLList;
        public var feed_desc:String;
        public var feed_link:String;

        //Setting up variables which help load the feeds

        private var feedXML:XML;
        //Create a loader to load an external URL
        private var loader:URLLoader = new URLLoader();


        public function Feed(inURL:String = "") {
            //Load the xml document
            loader.load(new URLRequest(inURL));
            loader.addEventListener(Event.COMPLETE,onLoaded);
        }

        //When the loader had loaded the xml document, pass that into a variable for use. 
        private function onLoaded(e:Event):void {
            feedXML = new XML(e.target.data);

            // break down the xml document elements into singular XML array lists

            //Feed details
            this.feed_title = feedXML.channel.title;
            this.feed_link = feedXML.channel.link;
            this.feed_desc = feedXML.channel.description;

            trace(this.feed_title);

        }

    }

}

任何帮助都将不胜感激：）

谢谢，

---

Geoff

如果问题是TechFeed（）构造函数中的

feed\u one.feed\u title

出现空值，那是因为您没有等待feed完成加载。 您需要做的是在加载和处理完数据后从提要中调度一个事件，在TechFeed中捕获它，然后根据需要使用公共变量（这也意味着您的提要类必须为EventDispatcher子类）：

在提要类中：

private function onLoaded(e:Event):void {
            feedXML = new XML(e.target.data);

            // break down the xml document elements into singular XML array lists

            //Feed details
            this.feed_title = feedXML.channel.title;
            this.feed_link = feedXML.channel.link;
            this.feed_desc = feedXML.channel.description;

            trace(this.feed_title);
            dispatchEvent(new Event(Event.COMPLETE));////Dispatch Event

        }

public function TechFeed() {
            trace(feed_one.feed_title);//This will trace "null"
            feed_one.addEventListener(Event.COMPLETE, dataLoaded);//add event listener
        }
private function dataLoaded(e:Event):void{
            var feed = Feed(e.currentTarget);
            feed.removeEventListener(Event.COMPLETE, dataLoaded);//remove event listener to prevent memory leaks
            trace(feed.feed_title);// This will trace the correct title
        }

在TechFeed类中：

private function onLoaded(e:Event):void {
            feedXML = new XML(e.target.data);

            // break down the xml document elements into singular XML array lists

            //Feed details
            this.feed_title = feedXML.channel.title;
            this.feed_link = feedXML.channel.link;
            this.feed_desc = feedXML.channel.description;

            trace(this.feed_title);
            dispatchEvent(new Event(Event.COMPLETE));////Dispatch Event

        }

public function TechFeed() {
            trace(feed_one.feed_title);//This will trace "null"
            feed_one.addEventListener(Event.COMPLETE, dataLoaded);//add event listener
        }
private function dataLoaded(e:Event):void{
            var feed = Feed(e.currentTarget);
            feed.removeEventListener(Event.COMPLETE, dataLoaded);//remove event listener to prevent memory leaks
            trace(feed.feed_title);// This will trace the correct title
        }

---

您的问题是，在从服务器返回数据之前，尝试从提要写入数据的时间
在本例中，我分配了一个函数，以便在加载数据时调用

包装{

    import flash.display.MovieClip;

    public class TechFeed extends MovieClip {

        private var feed_one:Feed;
        private var feed_two:Feed;
        private var feed_three:Feed;

        public function TechFeed() {
          feed_one= new Feed("http://feeds.feedburner.com/crunchgear",assignResults);
          feed_two= new Feed("http://feeds.mashable.com/Mashable",assignResults);
          feed_three= new Feed("http://www.engadget.com/rss.xml",assignResults);


        }

        public function assignResults(value:value):void{
          feed_name.text = value;
        }

    }

}






package  {

    import flash.net.URLLoader;
    import flash.events.Event;
    import flash.net.URLRequest;

    public class Feed {

        //Public variables to display feed info
        public var feed_title:XMLList;
        public var feed_desc:String;
        public var feed_link:String;

        //Setting up variables which help load the feeds

        private var feedXML:XML;
        //Create a loader to load an external URL
        private var loader:URLLoader = new URLLoader();

private var _callBackFunc:Function;
        public function Feed(inURL:String = "", callBackFunc:Function) {


           this._callBackFunc = callBackFunc;


            //Load the xml document
            loader.load(new URLRequest(inURL));
            loader.addEventListener(Event.COMPLETE,onLoaded);
        }

        //When the loader had loaded the xml document, pass that into a variable for use. 
        private function onLoaded(e:Event):void {
            feedXML = new XML(e.target.data);

            // break down the xml document elements into singular XML array lists

            //Feed details
            this.feed_title = feedXML.channel.title;
            this.feed_link = feedXML.channel.link;
            this.feed_desc = feedXML.channel.description;

            this._callBackFunc(this.feed_title);

        }

    }

}

---

感谢您的回复！但是我不确定dispatchEvent函数将包含什么？它与事件有什么关系（如果有的话）@Geoff我不确定我是否理解您的问题。是否要重新措辞？加载是异步操作，因此您必须等待XML加载，而不是读取“提要标题”value@turbosqel我怎么知道它什么时候结束？我不知道在答案中应该在dispatchEvent中添加什么…谢谢！您为我提供了一个很好的起点：）