Instantiating Objects
Although
it
may sound backward, let’s
assume that we have already created an object class. This assumption
isn’t too ludicrous, because ActionScript provides many
built-in classes, and the custom classes we’ll build will
behave similarly. Assuming we have an object class, we have to create
a specific object instance (i.e., a copy) based
on the class. For example, ActionScript provides the
Array
object class, but it is up to us to create
individual arrays.
To create an instance of an object (i.e.,
instantiate the object), we use the
new
operator with a constructor
function, which is used to initialize the object. The
general syntax is:
new ConstructorFunction
( )
Let’s instantiate our first object using a constructor
that’s already built into ActionScript: the Object(
)
constructor. The Object(
)
constructor creates a completely generic object (hence
its name), the foundation object type upon which all other object
types are based. The following code creates a new generic object:
new Object( )
When we instantiate an object, we normally store the resulting instance in a variable, array element, or object property for later access. For example:
var myObject = new Object( );
Instantiating an object in this manner gives us an empty object with no properties and only two very general methods. Generic objects, hence, are of limited use—the real power of objects comes with specialized object classes. Before we learn how to make our own classes, we’ll see how to use object ...
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