MACROMEDIA FLASH 8-LEARNING ACTIONSCRIPT 2.0 IN FLASH, Manual

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298 Classes
About calling built-in object methods
You call an object’s method by using the dot (
.
) operator followed by the method. For
example, the following code creates a new Sound object and calls its
setVolume()
method:
var my_sound:Sound = new Sound(this);
my_sound.setVolume(50);
For examples of working with methods of the built-in MovieClip class, see Chapter 11,
“Working with Movie Clips,” on page 351 . For examples of working with methods of the
built-in TextField, String, TextRenderer, and TextFormat classes, see Chapter 12, “Working
with Text and Strings,” on page 381 .
About class (static) members
Some built-in ActionScript classes have class members ( static members ). Class members
(properties and methods) are accessed or invoked on the class name, not on an instance of the
class. Therefore, you don’t create an instance of the class to use those properties and methods.
For example, all the properties of the Math class are static. The following code invokes the
max()
method of the Math class to determine the larger of two numbers:
var largerNumber:Number = Math.max(10, 20);
trace(largerNumber); // 20
For more information on static methods of the Math class, and examples of using them, see
Math in the
ActionScript 2.0 Language Reference .
Excluding classes
To reduce the size of a SWF file, you might want to exclude classes from compilation but still
be able to access and use them for type checking. For example, you might want to do this if
you are developing an application that uses multiple SWF files or shared libraries, especially
those that access many of the same classes. Excluding classes helps you avoid duplicating
classes in those files.
For more information on excluding classes, see the following topics:
■
“Preloading class files” on page 299