Flex Preloader without Flash CS - apache-flex

Question

I have been digging for custom Flex preloaders and they all seem to rely on the same template:An SWC is created with Flash CS5 and then used by Flash Builder using the "preloader" application property.
I don't own Flash CS, and it feels that Flash builder should be able to do the trick.
I created a Library Project in Flash Builder with the following bare bones code:
package loader
{
import flash.display.DisplayObject;
import flash.events.Event;
import flash.utils.getTimer;
import mx.events.RSLEvent;
import mx.preloaders.DownloadProgressBar;
import mx.preloaders.SparkDownloadProgressBar;
public class Preloader extends SparkDownloadProgressBar
{
[Embed(source="loaderlogo.png")] public var logoClass:Class;
private var _displayStartCount:uint = 0;
private var _initProgressCount:uint = 0;
private var _downloadComplete:Boolean = false;
private var _showingDisplay:Boolean = false;
private var _startTime:int;
// private var preloaderDisplay:PreloaderDisplay;
private var rslBaseText:String = "loading: ";
public function Preloader()
{
super();
}
/**
* Event listener for the <code>FlexEvent.INIT_COMPLETE</code> event.
* NOTE: This event can be commented out to stop preloader from completing during testing
*/
override protected function initCompleteHandler(event:Event):void
{
dispatchEvent(new Event(Event.COMPLETE));
}
/**
* Creates the subcomponents of the display.
*/
override protected function createChildren():void
{
var img:DisplayObject = new logoClass();
img.x = Math.round( ( stageWidth - img.width) / 2);
img.y = Math.round( ( stageHeight - img.height) / 2);
addChild( img);
var dpb:DownloadProgressBar = new DownloadProgressBar();
dpb.x = img.x + 100;
dpb.y = img.x + 100;
dpb.width = 170;
dpb.height = 20;
addChild( dpb);
}
/**
* Event listener for the <code>RSLEvent.RSL_PROGRESS</code> event.
**/
override protected function rslProgressHandler(evt:RSLEvent):void {
if (evt.rslIndex && evt.rslTotal) {
//create text to track the RSLs being loaded
rslBaseText = "loading RSL " + evt.rslIndex + " of " + evt.rslTotal + ": ";
}
}
/**
* indicate download progress.
*/
override protected function setDownloadProgress(completed:Number, total:Number):void {
}
/**
* Updates the inner portion of the download progress bar to
* indicate initialization progress.
*/
override protected function setInitProgress(completed:Number, total:Number):void {
}
/**
* Event listener for the <code>FlexEvent.INIT_PROGRESS</code> event.
* This implementation updates the progress bar
* each time the event is dispatched.
*/
override protected function initProgressHandler(event:Event):void {
var elapsedTime:int = getTimer() - _startTime;
_initProgressCount++;
if (!_showingDisplay && showDisplayForInit(elapsedTime, _initProgressCount)) {
_displayStartCount = _initProgressCount;
show();
// If we are showing the progress for the first time here, we need to call setDownloadProgress() once to set the progress bar background.
setDownloadProgress(100, 100);
}
if (_showingDisplay) {
// if show() did not actually show because of SWFObject bug then we may need to set the download bar background here
if (!_downloadComplete) {
setDownloadProgress(100, 100);
}
setInitProgress(_initProgressCount, initProgressTotal);
}
}
private function show():void
{
// swfobject reports 0 sometimes at startup
// if we get zero, wait and try on next attempt
if (stageWidth == 0 && stageHeight == 0)
{
try
{
stageWidth = stage.stageWidth;
stageHeight = stage.stageHeight
}
catch (e:Error)
{
stageWidth = loaderInfo.width;
stageHeight = loaderInfo.height;
}
if (stageWidth == 0 && stageHeight == 0)
return;
}
_showingDisplay = true;
createChildren();
}
}
}
For short, it's loading a logo and a progress bar
It displays a preloader, but really late in the loading process. As if it was being loaded after Flex.
Do I need to compile this in CS5 to completely avoid use of MX/Spark?

Answer 1

You shouldn't use any components in preloader. Try to remove you imports (Ctrl+Shift+O):
import mx.controls.Image;
import spark.components.Label;
Use TextField and Loader instead if needed. I'm not sure about DownloadProgressBar component.
Also don't use create children in preloader. Here is one working sample:
package {
import flash.display.MovieClip;
import flash.display.Sprite;
import flash.events.Event;
import flash.events.ProgressEvent;
import flash.text.TextField;
import flash.text.TextFormat;
import mx.core.mx_internal;
import mx.preloaders.SparkDownloadProgressBar;
use namespace mx_internal;
public class Preloader extends SparkDownloadProgressBar {
private var preloaderLogo : MovieClip;
private var loadingText : TextField;
private var loadingProgress : TextField;
private var _initProgressCount : uint = 0;
private var textFormat : TextFormat = new TextFormat("Verdana", 16, 0x666666, true);
public function Preloader() {
super();
textFormat.align = "center";
}
override public function set preloader(value : Sprite) : void {
super.preloader = value;
if (!preloaderLogo) {
preloaderLogo = new Assets.PRELOADER_LOGO; // kakaranet logo
var startX : Number = Math.round((stageWidth - preloaderLogo.width) / 2);
var startY : Number = Math.round(stageHeight / 2 - preloaderLogo.height) - 100;
preloaderLogo.x = startX;
preloaderLogo.y = startY;
loadingText = new TextField();
loadingProgress = new TextField();
loadingText.width = stageWidth;//to allow center align
loadingProgress.width = stageWidth;
loadingText.text = "Loading...";
loadingText.y = preloaderLogo.y + preloaderLogo.height + 20;
loadingProgress.text = "0%";
loadingProgress.y = loadingText.y + loadingText.textHeight + 10;
addChild(preloaderLogo);
addChild(loadingText);
addChild(loadingProgress);
loadingText.setTextFormat(textFormat);
loadingProgress.setTextFormat(textFormat);
}
}
override protected function progressHandler(event : ProgressEvent) : void {
super.progressHandler(event);
if (loadingProgress) {
loadingProgress.text = Math.floor(event.bytesLoaded / event.bytesTotal * 100) + "%";
loadingProgress.setTextFormat(textFormat);
}
}
override protected function completeHandler(event : Event) : void {
loadingText.text = "Ready!";
loadingText.setTextFormat(textFormat);
preloaderLogo.stop();
}
override protected function initProgressHandler(event : Event) : void {
super.initProgressHandler(event);
//similar to super
_initProgressCount++;
if (loadingProgress) {
loadingProgress.text = "100% / " + Math.floor(_initProgressCount / initProgressTotal * 100) + "%";
loadingProgress.setTextFormat(textFormat);
}
}
}
}