There is a lot of flex preloader tutorials all over the internet. If you take a closer look at each, you may notice those all extends DownloadProgressBar or SparkDownloadProgressBar classes. You may decide that these classes do not fit your needs, and it that case you can extend regular Sprite with IPreloaderDisplay implementation. Soon you realize there is some other Preloader in use, that communicates with your custom one through events. Following example contains a preloader implementation that renders a filled arc based on application load progress and RSL load progress. Lets have a look how to handle it properly.