Localizing Flex application preloader

Recently there was a request to localize labels on preloader of Flex application, such as "Initializing" and "Loading":



First of all I've provided modification for HTMl content page to path needed parameters with "FlashWars":

AC_FL_RunContent(
"src", "${swf}",
"width", "${width}",
"height", "${height}",
"align", "middle",
"id", "${application}",
"quality", "high",
"bgcolor", "${bgcolor}",
"name", "${application}",
"wmode", "transparent",
"FlashVars", "initLabel=Init Some Application&downloadLabel=Downloading Some Application",
"allowScriptAccess","sameDomain",
"type", "application/x-shockwave-flash",
"pluginspage", "http://www.adobe.com/go/getflashplayer",
"allowFullScreen", "true"
);

Populating "FlashVars" can be done dynamically for example if you have JSP page. In such case you can access needed bundle and get corresponding labels:

"FlashVars", "initLabel=<%= localizedInitLbl%>&downloadLabel=<%= localizedDownloadLbl%>"

Next step is to create custom preloader for your application and use it. Custom preloader is set to Flex application in next way:

<:mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
preloader="com.somecompany.preloader.DownloadProgressBarCustom">

Code of preloader is next:

package com.somecompany.preloader
{
import flash.events.Event;
import flash.geom.Rectangle;

import mx.preloaders.DownloadProgressBar;

public class DownloadProgressBarCustom extends DownloadProgressBar
{
public function DownloadProgressBarCustom()
{
super();
// Clear the initialization label till translation is received.
initializingLabel = "";
// Clear download label till translation is received.
downloadingLabel = "";
// Set the minimum display time to 5 seconds (for testing only).
//MINIMUM_DISPLAY_TIME = 5000;

this.addEventListener(Event.ADDED_TO_STAGE, addToStageHandler);
}

// Need to get parameters for label translation.
private function addToStageHandler(e:Event):void
{
//more safe to remove EventListener than using weak reference
this.removeEventListener(Event.ADDED_TO_STAGE, addToStageHandler);

var params:Object = this.stage.loaderInfo.parameters;
initializingLabel = params.hasOwnProperty("initLabel") ? params.initLabel : "Initializing";
downloadingLabel = params.hasOwnProperty("downloadLabel") ? params.downloadLabel : "Loading";
}

// More space for text.
override protected function get labelRect():Rectangle
{
return new Rectangle(5, 17, 170, 16);
}
}
}

Main idea is listen to "Added To Stage" event to have access to "FlashVars" with help of loaderInfo instance.

As result, you will have custom message on preloader: