Why is my action script event not firing? - actionscript-3

Question

Presently, I am attempting to add the ability to capture all the slides of a presentation to images and save them to disk. It works now where the first page is capture, then I want an async event to fire when the second page has loaded to capture that page, and so on. Here is where I have added an event listener, though I'm not sure if I should be using stage or this:
import flash.events.Event;
private var jpgEncoder:JPGEncoder;
// ...
private function init():void{
// ...
// Add async event to capture second page after loading
stage.loaderInfo.addEventListener(Event.COMPLETE,onLoadComplete);
// ...
}
private function onPrintButtonClicked():void {
// screen capture code
jpgEncoder = new JPGEncoder(90);
// Page 1 capture
bitmapData1 = new BitmapData(stage.width, stage.height);
bitmapData1.draw(stage, new Matrix());
// move to next page
var curPage:Page = PresentationModel.getInstance().getCurrentPage();
if (curPage != null) {
LOGGER.debug("Go to next page. Current page [{0}]", [curPage.id]);
pageCount++;
dispatchEvent(new GoToNextPageCommand(curPage.id));
} else {
LOGGER.debug("Go to next page. CanNOT find current page.");
}
}
private function onLoadComplete(e:Event)
{
// Get page 2 capture
bitmapData2 = new BitmapData(stage.width, stage.height);
bitmapData2.draw(stage, new Matrix());
// Copy two pages to one bitmap
var rect1:Rectangle = new Rectangle(0, 0, stage.width, stage.height);
var pt1:Point = new Point(0, 0);
bitmapData3 = new BitmapData(stage.width, stage.height * 2);
bitmapData3.copyPixels(bitmapData1, rect1, pt1)
var rect2:Rectangle = new Rectangle(0, 0, stage.width, stage.height);
var pt2:Point = new Point(0, stage.height);
bitmapData3.copyPixels(bitmapData2, rect2, pt2)
// Convert to image
var img:ByteArray = jpgEncoder.encode(bitmapData3);
var file:FileReference = new FileReference();
file.save(img, "capture1.jpg");
}
Does anyone have any ideas as to why the OnLoadComplete function is never called? FYI, here is the full source code: https://github.com/john1726/bigbluebutton/blob/master/bigbluebutton-client/src/org/bigbluebutton/main/views/MainToolbar.mxml
TIA

Answer 1

Please note that I've found that the stage was still null in the init() method so an exception was being thrown:
stage.loaderInfo.addEventListener(Event.COMPLETE,onLoadComplete);
Also, after resolving that stage error I found that I have been receiving this error using this tool: https://github.com/capilkey/Vizzy-Flash-Tracer
Error #2176: Certain actions, such as those that display a pop-up window, may only be invoked upon user interaction, for example by a mouse click or button press.
So the solution is either to re-work the UI so that there is a button press to prepare the files and a second button press to actually save the image or setup them mouseup and mousedown events to call different functions:
s:Button mouseDown="prepare_PDF()" mouseUp="save_PDF()"
Source: Flex's FileReference.save() can only be called in a user event handler -- how can I get around this?
Thank you!