ListAccImpl  - AS3 Flex

Pacote	spark.accessibility
Classe	public class ListAccImpl
Herança	ListAccImpl ListBaseAccImpl AccImpl AccessibilityImplementation Object

Versão da linguagem:

ActionScript 3.0

Versão de produto:

Flex 4

Versões de runtime:

Flash Player 10, AIR 1.5

ListAccImpl is the accessibility implementation class for spark.components.List.

When a Spark ListBase is created, its accessibilityImplementation property is set to an instance of this class. The Flash Player then uses this class to allow MSAA clients such as screen readers to see and manipulate the List. See the mx.accessibility.AccImpl and flash.accessibility.AccessibilityImplementation classes for background information about accessibility implementation classes and MSAA.

Children

The MSAA children of a list are its list items. The number of children is the number of items in the dataProvider, not just the number of visible renderers.

As described above, the accessibility of the list items is managed by the List; the accessibilityImplementation and accessibilityProperties of the item renderers are ignored by the Flash Player.

Role

The MSAA Role of a List is ROLE_SYSTEM_LIST.

The Role of each list item in the List is ROLE_SYSTEM_LISTITEM.

Name

The MSAA Name of a List is, by default, an empty string. When wrapped in a FormItem element, the Name is the FormItem's label. To override this behavior, set the List's accessibilityName property.

The Name of each list item is determined by the List's itemToLabel() method.

When the Name of the List or one of its items changes, a List dispatches the MSAA event EVENT_OBJECT_NAMECHANGE with the proper childID for a list item or 0 for itself.

Description

The MSAA Description of a List is, by default, an empty string, but you can set the List's accessibilityDescription property.

The Description of each list item is the empty string.

State

The MSAA State of a List is a combination of:

• STATE_SYSTEM_UNAVAILABLE (when enabled is false)
• STATE_SYSTEM_FOCUSABLE (when enabled is true)
• STATE_SYSTEM_FOCUSED (when enabled is true and the List has focus)
• STATE_SYSTEM_MULTISELECTABLE (when allowMultipleSelection is true)

The State of a list item is a combination of:

• STATE_SYSTEM_FOCUSABLE
• STATE_SYSTEM_FOCUSED (when focused)
• STATE_SYSTEM_SELECTABLE
• STATE_SYSTEM_SELECTED (when it has the caret)

When the State of the List or one of its items changes, a List dispatches the MSAA event EVENT_OBJECT_STATECHANGE with the proper childID for the list item or 0 for itself.

Value

A List or list item does not have an MSAA Value.

Location

The MSAA Location of a List or a list item is its bounding rectangle.

Default Action

A List does not have an MSAA DefaultAction.

The MSAA DefaultAction of a list item is "Double Click".

Performing the default action on a list item will cause it to be selected.

Focus

A List accepts focus. When it does so, it dispatches the MSAA event EVENT_OBJECT_FOCUS.

Selection

A List allows either a single or multiple list items to be selected, depending on the allowMultipleSelection property. When an item is selected, it dispatches MSAA event EVENT_OBJECT_SELECTION.

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