If you create many utility classes or include multiple ActionScript files to access commonly used functions, you might want to store them in a set of classes in their own package. You can import ActionScript classes and packages using the import statement. By doing this, you do not have to explicitly enter the fully qualified class names when accessing classes within ActionScript.

The following example imports the MyClass class in the MyPackage.Util package:

<?xml version="1.0"?>
<!-- usingas/AccessingPackagedClasses.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">

    <mx:Script><![CDATA[
        import MyPackage.Util.MyClass;

        private var mc:MyClass = new MyClass;

    ]]></mx:Script>

    <mx:Button id="myButton" label="Click Me" click="myButton.label=mc.returnAString()"/>

</mx:Application>
The executing SWF file for the previous example is shown below:

In your ActionScript code, instead of referring to the class with its fully qualified package name (MyPackage.Util.MyClass), you refer to it as MyClass.

You can also use the wildcard character (*) to import the entire package. For example, the following statement imports the entire MyPackage.Util package:

import MyPackage.Util.*;

Flex searches the source path for imported files and packages, and includes only those that are used in the final SWF file.

It is not sufficient to simply specify the fully qualified class name. You should use fully qualified class names only when necessary to distinguish two classes with the same class name that reside in different packages.

If you import a class but do not use it in your application, the class is not included in the resulting SWF file's bytecode. As a result, importing an entire package with a wildcard does not create an unnecessarily large SWF file.