ActionScript for Flash MX: The Definitive Guide, Second Edition

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

336

|

Chapter 13: Movie Clips

command first tries to convert it to a string, but because newClip1 looks to the inter-

preter like an

undefined variable, the conversion yields the empty string. Luckily, you

can again use the return value stored in

newClip_mc to refer to the newly created clip:

newClip_mc = _root.attachMovie("Symbol 1", newClip1, 0);

trace(newClip_mc); // Displays _level0.

// (the clip's name is an empty string!)

What if newName is specified as a legal identifier, such as ball_mc, that already refers to

an existing movie clip? Again, the attachMovie() command first tries to convert it to a

string, which (referring to Table 3-2 for string conversion of movie clips) yields the

interim string “_level0.ball_mc” for

newName. This series of conversions results in the

newly created movie clip having the incorrect name “_level0._level0.ball_mc”. Luck-

ily, yet again you can use the return value stored in

newClip_mc to refer to the newly

created clip properly:

//Assume ball_mc is an existing (valid) movie clip identifier

newClip_mc = _root.attachMovie("Symbol 1", ball_mc, 0);

trace(newClip_mc); // Displays "_level0._level0.ball_mc"

As you can see, life is much easier when we make sure to provide a string that con-

verts to a legal identifier for

newName.

Creating instances with createEmptyMovieClip( ...