Interface Statement - MACROMEDIA FLASH 8-FLASH LITE 2.X ACTIONSCRIPT LANGUAGE Reference

interface statement

interface InterfaceName [extends InterfaceName ] {}
Note: To use this keyword, you must specify ActionScript 2.0 and Flash Player 6 or later in
the Flash tab of your FLA file's Publish Settings dialog box. This keyword is supported only
when used in external script files, not in scripts written in the Actions panel.
Defines an interface. An interface is similar to a class, with the following important
differences:
Interfaces contain only declarations of methods, not their implementation. That is, every
■
class that implements an interface must provide an implementation for each method
declared in the interface.
Only public members are allowed in an interface definition; instance and class members
■
are not permitted.
The and
get set
■
Availability: ActionScript 2.0; Flash Lite 2.0
Example
The following example shows several ways to define and implement interfaces:
(in top-level package .as files Ia, B, C, Ib, D, Ic, E)
// filename Ia.as
interface Ia {
function k():Number; // method declaration only
function n(x:Number):Number; // without implementation
}
// filename B.as
class B implements Ia {
function k():Number {
return 25;
}
function n(x:Number):Number {
return x + 5;
}
} // external script or Actions panel // script file
var mvar:B = new B();
trace(mvar.k()); // 25
trace(mvar.n(7)); // 12
// filename c.as
class C implements Ia {
function k():Number {
return 25;
}
} // error: class must implement all interface methods
// filename Ib.as
204 ActionScript language elements
statements are not allowed in interface definitions.