ComboBoxAccImpl  - AS3 Flex

Paket	spark.accessibility
Klass	public class ComboBoxAccImpl
Arv	ComboBoxAccImpl DropDownListBaseAccImpl ListBaseAccImpl AccImpl AccessibilityImplementation Object

Språkversion:

ActionScript 3.0

Produktversion:

Flex 4

Körningsmiljöversioner:

Flash Player 10, AIR 1.5

ComboBoxAccImpl is the accessibility implementation class for spark.components.ComboBox.

When a Spark ComboBox 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 ComboBox. 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 ComboBox are its editable TextInput (with childID 1) and its list items (with childIDs 2, 3, ... n). The number of children is one plus the number of items in the dataProvider (not one plus the the number of visible renderers).

As described below, the accessibility of the TextInput and the list items is managed by the ComboBox; their accessibilityImplementation and accessibilityProperties are ignored by the Flash Player.

Role

The MSAA Role of a ComboBox is ROLE_SYSTEM_COMBOBOX.

The MSAA Role of the editable TextInput is ROLE_SYSTEM_TEXT.

The Role of each list item is ROLE_SYSTEM_LISTITEM.

Name

The MSAA Name of a ComboBox (as well as its editable TextInput) 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 ComboBox's accessibilityName property.

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

When the Name of the ComboBox or one of its items changes, a ComboBox 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 ComboBox, by default, an empty string, but you can set the ComboBox's accessibilityDescription property.

The Description of each list item is the empty string.

State

The MSAA State of a ComboBox 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 ComboBox has focus)
• STATE_SYSTEM_EXPANDED (when it is open)
• STATE_SYSTEM_COLLAPSED (when it is closed)

The State of the editable TextInput 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 ComboBox has focus)

The State of a list item is a combination of:

• STATE_SYSTEM_FOCUSABLE
• STATE_SYSTEM_FOCUSED (when it has focus)
• STATE_SYSTEM_SELECTABLE
• STATE_SYSTEM_SELECTED (when it is selected)

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

Value

The MSAA Value of a ComboBox is the MSAA Name of the currently selected list item or the text entered into the TextInput.

The Value of a list item is always the empty string.

When the Value of the ComboBox changes, a ComboBox dispatches the MSAA event EVENT_OBJECT_VALUECHANGE.

Location

The MSAA Location of a ComboBox, its TextInput, or one of its list items is its bounding rectangle.

Default Action

Neither the ComboBox or it's TextInput have an MSAA DefaultAction.

The DefaultAction of a list item is "Double Click". Performing this action will select the item.

Focus

The ComboBox itself can receive focus, as well as its list items (either while the ComboBox is collapsed or expanded).

Selection

The ComboBox allows a single item to be selected, in which case an EVENT_OBJECT_SELECTION event is fired.

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