AS3 Returning a variable from an event listener function

问题

I'm trying to return XML from an event complete back to the main function, but can't figure out how to do it.

Here's the functions I'm calling:

Main File:

public var mySendAndLoad:SendAndLoad = new SendAndLoad(); 

mySendAndLoad.sendData(url,variables)

The mySendAndLoad class:

package 
{

    import flash.events.*;
    import flash.net.*;
    import flash.xml.XMLDocument;

    public class SendAndLoad
    {
        public var xml:XML = new XML();
        public var xmlList:XMLList;

        public function SendAndLoad()
        {
        }
        public function sendData(url:String, _vars:URLVariables):String
        {
            var request:URLRequest = new URLRequest(url);
            var loader:URLLoader = new URLLoader();
            loader.dataFormat = URLLoaderDataFormat.TEXT;
            request.data = _vars;
            request.method = URLRequestMethod.POST;
            loader.addEventListener(Event.COMPLETE, handleComplete);
            loader.addEventListener(IOErrorEvent.IO_ERROR, onIOError);
            loader.load(request);
        }
        private function handleComplete(event:Event):String
        {
            var loader:URLLoader = URLLoader(event.target);
            xml = XML(loader.data);
            xmlList = xml.children();
            return(xmlList[1]);
        }
        private function onIOError(event:IOErrorEvent):void
        {
            trace("Error loading URL.");
        }
    }
}

What I want to happen is have the xmlList come back to the main file. But since it isn't in the event I called (sendData) it doesn't get brought back.

Any ideas?

回答1:

package 
{

import flash.events.*;
import flash.net.*;
import flash.xml.XMLDocument;

//THIS CLASS EXTENDS EVENTDISPATCHER SO IT CAN DISPATCH EVENTS
public class SendAndLoad extends EventDispatcher
{
    public var xml:XML = new XML();
    public var xmlList:XMLList;

    public function SendAndLoad()
    {
        super(null);
    }
    public function sendData(url:String, _vars:URLVariables):void
    {
        var request:URLRequest = new URLRequest(url);
        var loader:URLLoader = new URLLoader();
        loader.dataFormat = URLLoaderDataFormat.TEXT;
        request.data = _vars;
        request.method = URLRequestMethod.POST;
        loader.addEventListener(Event.COMPLETE, handleComplete);
        loader.addEventListener(IOErrorEvent.IO_ERROR, onIOError);
        loader.load(request);
    }
    private function handleComplete(event:Event):void
    {
        var loader:URLLoader = URLLoader(event.target);
        xml = XML(loader.data);
        xmlList = xml.children();


        //NEW CODE
        var evt:Event=new Event(Event.COMPLETE);
        dispatchEvent(evt);
        //return(xmlList[1]);
    }
    private function onIOError(event:IOErrorEvent):void
    {
        trace("Error loading URL.");
    }
}

}

and in the main file

public var mySendAndLoad:SendAndLoad = new SendAndLoad(); 
mySendAndLoad.addEventListener(Event.COMPLETE, xmlLoadCompleted);
mySendAndLoad.sendData(url,variables)

private function xmlLoadCompleted(e:Event):void {
    var childToUse:XML=mySendAndLoad.xmlList[1];
    //whatever else you want to do 
}

回答2:

Just dispatch an event

package 
{

    import flash.events.Event;
    import flash.display.Sprite;
    import flash.events.*;
    import flash.net.*;
    import flash.xml.XMLDocument;

    public class SendAndLoad extend Sprite
    {
        public var xml:XML = new XML();
        public var xmlList:XMLList;

        public function SendAndLoad()
        {
        }
        public function sendData(url:String, _vars:URLVariables):String
        {
            var request:URLRequest = new URLRequest(url);
            var loader:URLLoader = new URLLoader();
            loader.dataFormat = URLLoaderDataFormat.TEXT;
            request.data = _vars;
            request.method = URLRequestMethod.POST;
            loader.addEventListener(Event.COMPLETE, handleComplete);
            loader.addEventListener(IOErrorEvent.IO_ERROR, onIOError);
            loader.load(request);
        }
        private function handleComplete(event:Event):String
        {
            var loader:URLLoader = URLLoader(event.target);
            xml = XML(loader.data);
            xmlList = xml.children();


           // return(xmlList[1]);
           this.dispatchEvent( new Event( 'ONDATA' ) );
        }
        private function onIOError(event:IOErrorEvent):void
        {
            trace("Error loading URL.");
        }
    }
}


// usage
var sender:SendAndLoad = new SendAndLoad( );
sender.addEventListener( 'ONDATA', myXMLLoaded);
sender.sendData( url, _vars )

function myXMLLoaded( e:Event ):void{
  trace(sender.xml);
}

回答3:

Without serious modifications you have two options:

1. Your SaveAndLoad class to derrive EventDispatcher and send a custom event with the data in it.

2. More clean/non obtrusive is to make sendData method modifications:

   public function sendData(url:String, _vars:URLVariables, resultHandler:Function=null):String
   {
       loader.addEventListener(Event.COMPLETE, resultHandler);
   }
   

You can pass a function defined in your main file, still have the ability to attach inner listeners for whatever you want in SaveAndLoad class, and you will have your data.

回答4:

You must use dispatchEvent;

first declare to it public class personal_info extends EventDispatcher {

and you must define listener into that class dispatchEvent(new Event(Event.COMPLETE));

回答5:

you must declare variable such as public
public var variable:String;

You must use dispatchEvent;

first declare to it
   public class personal_info extends EventDispatcher {
   ...

and you must define listener into that complete event
   variable = "variable";
   dispatchEvent(new Event(Event.COMPLETE));
   ...

And you must call just like calling normal event in another class
   var sample:SampleClass = new SampleClass ();
   sample.addEventListener(Event.COMPLETE , cComplete);

And you can use that variable in this class like:
  private fonction (e:Event):void {
    trace (e.target.variable);
}

来源：https://stackoverflow.com/questions/7587665/as3-returning-a-variable-from-an-event-listener-function