dispatch change value and start tween - actionscript-3

Question

I try to make simple scorebug. It’s feed from external XML file.
I want to start an animation when score changing, but i doesn’t found event listener or dispatcher to get change of value.
var myTimer:Timer = new Timer(100);
myTimer.addEventListener(TimerEvent.TIMER, timerListener);
myTimer.start();
function timerListener (e:TimerEvent):void
{
var myXMLLoader:URLLoader = new URLLoader();
myXMLLoader.load(new URLRequest("Xml.xml"));
myXMLLoader.addEventListener(Event.COMPLETE, processXML);
function processXML (e:Event):void
{
var myXML:XML = new XML(e.target.data);
ShotClock.text = myXML.timestamp;
GameClock.text = myXML.Clock;
HS.HomeScore.text = myXML.HomeScore;
AS.AwayScore.text = myXML.AwayScore;
Period.text = myXML.Period;
AwayTeam.text = myXML.AwayName;
HomeTeam.text = myXML.HomeName;
}
if ( (myXML.HomeScore).CHANGE )
{ var myTween:Tween = new Tween(HS.HomeScore, "alpha", Strong.easeIn, 0, 1, 1, true); }
}

Answer 1

You need to change the logic of loading. Instead of starting timed loadings, which won't be accurate 100 ms anyway, could lag, could fail, could arrive in order other than you issued them, etc., you need a single-thread asynchronous loop that does, simply, the following:
Start data loading.
(async pause)
Handle the loaded data.
Get XML data from loaded text.
Parse XML attributes.
Check if the score variable changed and trigger the things you want to.
Wait 100 ms.
(async pause)
Go to step №1.
Something like that:
var theLoader:URLLoader;
var theScore:Number = 0;
var theTimer:Timer;
// Start the tracking routine.
trackNext();
function trackNext():void
{
theLoader = new URLLoader;
theLoader.addEventListener(Event.COMPLETE, onXML);
// Error tracking is a must or the logic flow
// might just stop when you least expect it to.
theLoader.addEventListener(IOErrorEvent.IO_ERROR, onError, false, 0, true);
theLoader.load(new URLRequest("xml.xml"));
}
function onXML(e:Event):void
{
// Sanity check. There should be only one valid URLLoader instance.
if (e.target != theLoader)
{
return;
}
var X:XML;
try
{
X = new XML(theLoader.data);
}
catch (fail:Error)
{
// Processing the case where data is loaded successfully,
// but it is not a valid XML String.
onError(e);
return;
}
// Here's the place for your code
// that extracts data from XML.
// ...
// Get the new score value.
var aScore:Number = X.HomeScore;
// Compare it to previous value.
if (aScore != theScore)
{
// ATTENTION!!! THIS IS THE PLACE YOU ARE LOOKING FOR!!!
// Trigger things if the new score is any different.
// ...
// Keep the new score value.
theScore = aScore;
}
finishLoading();
}
// This method just ignores an error, think of it
// as of blank to process the exceptional cases.
function onError(e:Event):void
{
// Sanity check. There should be only one valid URLLoader instance.
if (e.target != theLoader)
{
return;
}
finishLoading();
}
// Call it finishLoading(true) to stop the tracking routine.
function finishLoading(thenstop:Boolean = false):void
{
// Dispose of the URLLoader instance if any.
if (theLoader)
{
var aLoader:URLLoader = theLoader;
theLoader = null;
aLoader.removeEventListener(Event.COMPLETE, onXML);
try
{
aLoader.close();
}
catch (fail:Error)
{
// Do nothing about it.
}
}
finishTimer();
if (thenstop)
{
return;
}
// Wait 100 ms to give Flash Player a breather
// before starting to load the file once more.
theTimer = new Timer(100, 1);
theTimer.addEventListener(TimerEvent.TIMER, onTime);
theTimer.start();
}
function finishTimer():void
{
// Dispose of the Timer instance if any.
if (theTimer)
{
theTimer.removeEventListener(TimerEvent.TIMER, onTime);
theTimer.stop();
theTimer = null;
}
}
function onTime(e:TimerEvent):void
{
// Now go for the next iteration.
finishTimer();
trackNext();
}