User Guide

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Import the component classes
Each component is associated with an ActionScript class file that defines its methods and
properties. In this section of the tutorial, you will add ActionScript code to import the classes
associated with the application’s components. For some of these components, you have
already added instances to the Stage. For others, you will add ActionScript later in the tutorial
to create instances dynamically.
The import statement creates a reference to the class name and makes it easier to write
ActionScript for the component. The import statement enables you to refer to the class by its
class name rather than its complete name, which includes the package name. For example,
after you create a reference to the ComboBox class file with an import statement, you can
refer to instances of the combo box with the syntax
instanceName:ComboBox, rather than
instanceName:mx.controls.ComboBox.
A package is a directory that contains class files and resides in a designated classpath directory.
You can use a wild card character to create references to all the classes in a package: for
example, the syntax
mx.controls.* creates references to all classes in the controls package.
(When you create a reference to a package with a wild card, the unused classes are dropped
from the application when it is compiled, so they don’t add any extra size.)
For the application in this tutorial, you need the following packages and individual classes:
UI Components Controls package This package contains classes for the user interface
control components, including ComboBox, DataGrid, Loader, TextInput, Label,
NumericStepper, Button, and CheckBox.
UI Components Containers package This package contains classes for the user interface
container components, including Accordion, ScrollPane, and Window. As with the controls
package, you can create a reference to this package by using a wild card.
DataGridColumn class This class lets you add columns to the DataGrid instance and
control their appearance.
WebService class This class populates the ComboBox instance with a list of problems or
offenses. For this class, you will also need to import the WebServiceClasses item from the
Classes common library. This item contains compiled clip (SWC) files that you will need in
order to compile and generate the SWF file for your application.
Cart class A custom class provided with this tutorial, the Cart class defines the functioning
of the shopping cart that you will create later. (To examine the code in the Cart class file, open
the cart.as file located in the component_application folder with the application FLA and
SWF files).