Beginning ActionScript 2.0

Chapter 8. Pre-Loading Movies

When loading external content, situations frequently occur in which you need to wait until the content has completely loaded before you can work with that content. You also may have some external content that is quite large, and you just want to provide some feedback on the load progress.

Pre-loaders are useful any time content needs to be loaded, such as when the main movie is initially loaded, when movies are requested on demand, when images are loaded, or even when large amounts of XML data need to be transferred from a server. A pre-loader ensures that the content has completely loaded before allowing it to run. Once the content starts to download, it is periodically polled to see how many bytes have been loaded. When the number of bytes loaded is the same as the total number of bytes, the movie can proceed with the next step.

This chapter looks at a number of different pre-loading approaches. You go into the guts of creating one yourself so that you can see how a pre-loader actually works, explore the MovieClipLoader class, and learn to use the Loader and ProgressBar components. Finally you examine pre-loaders in the context of two project architectures. The first is the monolithic movie approach where all content is contained in a single .swf file. The second is the split-up movie approach, where a smaller shell is initially loaded, and subsequent content is loaded on demand.

Using a Custom Pre-Loader

The main tools you need to create a pre-loader ...