11.2 The Flash Document (.fla file)

Every Flash application must include at least one Flash document ( .fla file). The Flash document is the source file from which a Flash movie ( .swf file) is exported. The Flash movie is what's actually displayed in the Flash Player (i.e., the Flash runtime environment). Many Flash applications are broken down into multiple .swf files that are loaded individually at runtime. For example, one .swf file might be a single level in a video game, whereas another .swf file might be a self-contained animation or the "Contact Us" section of a web site. Even in these multiple- .swf file scenarios, there's always a single, base .swf file on which the rest of the application is built. Sometimes, the base .swf file simply acts as an empty container, used only to display load progress for the rest of the application. At the other extreme, the entire application resides in the base .swf file directly, and no external .swf files are loaded.

Our basic application framework falls into the last category ”it includes a single .swf file only and, hence, requires only one .fla file. However, our application framework does not preclude the use of other .swf files down the road that might contain different sections of a web site, different stages in a form or quiz, or different levels in a video game.

To create our application's main .fla file, follow these steps:

1. In the Flash authoring tool, choose File New.

2. Use File Save As to save the Flash document as AppName.fla in the AppName/source directory.

We'll return to the .fla file in a moment. Right now, let's move on to our application's classes.