Flash Reference Guide

Flash movies are famous for relatively small file sizes. Even so, it is amazing how large those "compact" files can get when audio and a lot of imported graphics are used in a movie. Fortunately, Flash can download large graphics, complex scenes, and even whole movies as the rest of the movie is playing. This significantly improves the experience a customer has with your site. This optimization technique is called preloading, and I’ll show you how to do it with just a dab of ActionScript.

To begin with, you’ll write a simple script that will play an animation while the rest of the movie preloads before playing. This is similar to the many "Movie is downloading, please wait..." animations seen on Web sites.

Begin by opening a file and save it as Simple_Preloader.fla. The movie opens up with a default of just one scene. For the preload script to work, a second scene must be added. Add a second scene by choosing Insert > Scene.

The preloader script is going to be placed into scene 1. Before we do this, let’s add some content to scene 2. Open scene 2. Add two layers: call one layer "Scripts" and the other layer "Content." Make each layer five frames long.

Select the Content layer and add the following text: "This is scene 2."

In a production Flash movie, the Content layer is where you would place the main movie. scene 2 can be as large and long as you like. When you have finished with Simple_Preloader, experiment with it by adding a scene from a complex animation that you have written.

Select the Scripts layer. Choose frame 5 and open the ActionScript Inspector. From Basic Actions, drag a Stop action into the ActionScript editor window.

Now let’s add the preload script itself. This is the guts of our project.

Open scene 1. Add one layer and name it "Preload." Make the Preload layer five frames long. Change each frame into a keyframe (keyboard shortcut F6). Converting the frames to keyframes will allow scripts and animation to be added.

Select frame 1. Using the Text tool, add the word "Loading" in the center of the stage. Use 12-point Arial Black for the font.

Copy the word "Loading" from frame 1 and paste it into frames 2-5. The word should be in the same place for each frame. Select frame 2. Double-click the word "Loading" to open it in edit mode. Immediately after the word, add a single period.

Select frame 3 and edit the word "Loading" by adding two periods after the word. Add three periods after the word on frame 4 and four periods on frame 5. When the animation plays, it will have the word "Loading" and a growing string of periods animated after it.

Select frame 1. Open the ActionScript Inspector. From Basic Actions, drag "If Frame Is Loaded." Apply the settings to scene 2 and frame 5.

This script tells Flash that it must preload all of the content up to frame 5 of scene 2. If the animation is longer in scene 2, the number of frames should be extended. For instance, a movie with 550 frames should have the frame number changed to 550. All content—including audio, graphics, and scripted content—will be preloaded with this script.

Drag an instance of the "Go To" action. Apply the settings to scene 2 and frame 1. This action tells Flash what to do when all of the frames of scene 2 are loaded. In this case, the movie automatically goes to and begins playing frame 1 of scene 2.

Choose frame 5. From the ActionScript Inspector, drag "Go To" and enter the settings scene 1, frame 1. This will cause the animation to keep repeating until all of the content in scene 2 is loaded.

The movie can now be tested. Press F12 to preview in your Web browser. You will notice that while scene 2 is loading, the animation of the "Loading..." keeps playing. The more content in scene 2, the longer the preload scene will remain visible. The movie in scene 2 is very short. To see the full effect of the preload script, import an MP3 file into scene 2. Most MP3 files are in excess of 1 MB in file size. When placed on a Web site, it will allow you to view the preload script in action while the MP3 downloads.

Preloading allows you to create movies that have the same impact to a customer whether they are accessing the Internet on a slow dial-up modem or a high-speed broadband connection. The above script allows for a great deal of flexibility. You could have a company logo animate for the first scene, or a simple Flash game, or even a short presentation outlining what is going to be covered in the main movie. The possibilities are endless.