ActionScript for Flash MX: The Definitive Guide, Second Edition

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Chapter 13: Movie Clips

Load movie execution order

The loadMovie() function is not immediately executed when it appears in a state-

ment block. In fact, it is not executed until all other statements in the block have fin-

ished executing.

We cannot access an externally loaded movie’s properties or methods

in the same statement block as the loadMovie() invocation that loads it

into the Player.

Because loadMovie() loads an external file (usually over a network), its execution is

asynchronous. That is, loadMovie() may finish at any time, depending on the speed

of the file transfer. Therefore, before we access a loaded movie, we should always

check that the movie has finished transferring to the Player. We do so with what’s

commonly called a preloader—code that checks how much of a file has loaded

before allowing some action to take place. Preloaders can be built with the

_totalframes and _framesloaded movie clip properties and the getBytesLoaded() and

getBytesTotal() movie clip methods. See the appropriate entries under the MovieClip

class in the Language Reference for sample code.

Movie and Instance Stacking Order

All movie clip instances and externally loaded movies displayed in the Player reside

in a visual stacking order akin to a deck of cards. When instances or externally

loaded ...