UILoader.content stays null after load

Question

I've started with a new Flash file and wanted to toy around with loading images and resizing the UILoader to the size of the loaded image. I've added a UILoader (instance name: loadImage) component to the main timeline and added the following code in the Actions window:
loadImage.source = "bookmark.png";
trace( loadImage.content );
The image displays properly after compiling and viewing the SWF. However, loadImage.content returns null, instead of the DisplayObject that contains the image. This way, trying to resize the UIloader according to the loaded image doesn't work, since I can't access variables of an object that hasn't been initialized.
All the documentation states that loadImage.content should contain the DisplayObject that's loaded after setting loadImage.source or using loadImage.load( new URLRequest( "bookmark.png" ) ) (which also has the same problem). So I'm stumped.
Can anyone help me out?

Answer 1

The content is only defined when the loading has completed, which you need to set up an event listener to detect.
loadImage.source = "bookmark.png";
loadImage.addEventListener(Event.COMPLETE,imageLoadListener);
function imageLoadListener(e:Event):void{
trace( loadImage.content );
loading from an external source is 'asynchronous' which basically means actionscript continues to execute while its happening. You need to set up listeners to run when events happen for the asynchronous calls you make (in this case, setting the source property does that too, with autoLoad defaulting to true).