User Guide
RadioButton component 621
RadioButton component
The RadioButton component lets you force a user to make a single choice within a set of choices.
This component must be used in a group of at least two RadioButton instances. Only one
member of the group can be selected at any given time. Selecting one radio button in a group
deselects the currently selected radio button in the group. You set the
groupName parameter to
indicate which group a radio button belongs to.
A radio button can be enabled or disabled. A disabled radio button doesn’t receive mouse or
keyboard input. When the user clicks or tabs into a RadioButton component group, only the
selected radio button receives focus. The user can then use the following keys control it:
For more information about controlling focus, see “Creating custom focus navigation”
on page 50 or “FocusManager class” on page 419.
A live preview of each RadioButton instance on the Stage reflects changes made to parameters in
the Property inspector or Component inspector during authoring. However, the mutual exclusion
of selection does not display in the live preview. If you set the selected parameter to true for two
radio buttons in the same group, they both appear selected even though only the last instance
created will appear selected at runtime. For more information, see “RadioButton parameters”
on page 622.
When you add the RadioButton component to an application, you can use the Accessibility
panel to make it accessible to screen readers. First, you must add the following line of code to
enable accessibility:
mx.accessibility.RadioButtonAccImpl.enableAccessibility();
You enable accessibility for a component only once, regardless of how many instances you have of
the component. For more information, see Chapter 17, “Creating Accessible Content,” in Using
Flash.
Using the RadioButton component
A radio button is a fundamental part of any form or web application. You can use radio buttons
wherever you want a user to make one choice from a group of options. For example, you would
use radio buttons in a form to ask which credit card a customer wants to use.
Key Description
Up Arrow/Right
Arrow
The selection moves to the previous radio button within the radio button group.
Down Arrow/
Left Arrow
The selection moves to the next radio button within the radio button group.
Tab Moves focus from the radio button group to the next component.
CHAPTER 6
Components Dictionary