The custom preloader class extends Sprite and implements the IPreloaderDisplay class. Once the Sprite’s ‘root’ property becomes available, you can use the standard AS3 way of accessing flashvars, namely:

var flashvars:Object = root.loaderInfo.parameters;

This code should be used once the ‘root’ property has been initialised – for example in the ‘initialize()’ method defined by the IPreloaderDisplay interface:

public function initialize():void
{
     var flashvars:Object = root.loaderInfo.parameters;
}

Just for reference, compare the above approach with the standard Flex method of accessing flashvar parameters – which becomes possible once the main Application instance has been created:

var flashvars:Object = Application.application.parameters