Preloaders in AS3: The best and only way of doing it!

And a new way to! (Damn that sounded cocky! Hahaha! )
I recently discovered a new way of prelaoding content in the Flash Player. By passing an extra argument to the compiler. At work an at home i use FDT for creating and compiling my Flash content and there was always the problem with preloading. There are several ways of how to go about it.

• Create a preloader.swf and let that file load in the main site/application. (As described here)
• Passing the loaderinfo (As described here)

And then there is the ‘frame two compiler’ method.Let me be clear, this is not something I have discovered or invented, merely something I have found.
Here is how to do it:
When compiling from within FDT and creating your launcher file (also included in the download at the end of this article) you can add extra arguments to the fcsh compiler. The standard line i use is:

-default-size 400 320 -default-frame-rate 31 -default-background-color 0xFFFFFF -library-path{flexSDK}/frameworks/locale /en_US

What you need to add to make use of the ‘frame two’ method is add the following (The stacktraces is not needed for the frame two option but very handy to use when debugging, I put it in standard in every project I use. ):

-verbose-stacktraces=true -frame two nl.funkymonkey.preloading.Application

What the above code does is it takes the class with the name (and classpath) of “nl.funkymonkey.preloading.Application” and places it on the second frame called “two”. You can use the “-frame” compiler option as many times as you want for adding even more frames. (For a second preloader or other content that needs to be loaded)

Make sure the MAIN_CLASS attribute is set yo your Preloader.as in your Application.launch file. Like so:

The code that makes sure the correct class file is loaded after the preloader is this:

	protected var APP_CLASS : String = "nl.funkymonkey.preloading.Application";

	private function init() : void {
		trace( "this is the preloader" );

		var AppClass : Class = Class( getDefinitionByName( APP_CLASS ) );
		if(AppClass) {
			var application : IApplication = new AppClass( ) as IApplication;
			addChild( application as DisplayObject );
			startApplication( application );
		}
	}

	/**
	 * Start the application
	 *
	 * @param app:IApplication the application that is loaded
	 */
	protected function startApplication(app : IApplication) : void {
		trace( "start app" );
		app.start( );
	}

The complete Eclipse FDT project, the launcher file including the compiler arguments and the complete code can be found here.This can also be used in Flash Builder or any other editor that allows you to pass arguments to the fcsh compiler.

Let me know if you run into any problems!

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