DropDownListBaseAccImpl

Package	spark.accessibility
Class	public class DropDownListBaseAccImpl
Inheritance	DropDownListBaseAccImpl ListBaseAccImpl AccImpl AccessibilityImplementation Object
Subclasses	ComboBoxAccImpl

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

DropDownListAccImpl is the accessibility implementation class for spark.components.supportClasses.DropDownListBase.

Although ComboBox has its own accessibility implementation subclass, DropDownList simply uses the one for DropDownListBase. Therefore, the rest of this description refers to the commonly-used DropDownList component rather than the DropDownListBase base class.

When a Spark DropDownList 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 DropDownList. 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 DropDownList 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 below, the accessibility of the list items is managed by the DropDownList; the accessibilityImplementation and accessibilityProperties of the item renderers are ignored by the Flash Player.

Role

The MSAA Role of a DropDownList is ROLE_SYSTEM_COMBOBOX.

The Role of each list item is ROLE_SYSTEM_LISTITEM.

Name

The MSAA Name of a DropDownList 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 DropDownList's accessibilityName property.

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

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

The Description of each list item is the empty string.

State

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

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

Value

The MSAA Value of a DropDownList is the MSAA Name of the currently selected list item.

The Value of each list item is the empty string.

When the Value of the DropDownList changes, it dispatches the MSAA event EVENT_OBJECT_VALUECHANGE.

Location

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

Default Action

A DropDownList does not have an MSAA DefaultAction

The DefaultAction of a list item is "Double click".

Focus

The DropDownList itself can receive focus, as well as its list items (either while the DropDownList is collapsed or expanded). The EVENT_OBJECT_FOCUS is fired when this happens.

Selection

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

Public Properties

	Property		Defined By
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		errno : uint Indicates an error code.	AccessibilityImplementation
		stub : Boolean Used to create a component accessibility stub.	AccessibilityImplementation

Protected Properties

	Property		Defined By
		eventsToHandle : Array [read-only] All subclasses must override this function by returning an array of strings of the events to listen for.	AccImpl
		master : UIComponent A reference to the UIComponent instance that this AccImpl instance is making accessible.	AccImpl
		role : uint Accessibility role of the component being made accessible.	AccImpl

Public Methods

	Method		Defined By
		DropDownListBaseAccImpl(master:UIComponent) Constructor.	DropDownListBaseAccImpl
		accDoDefaultAction(childID:uint):void An IAccessible method that performs the default action associated with the component that this AccessibilityImplementation represents or of one of its child elements.	AccessibilityImplementation
		accLocation(childID:uint):* MSAA method for returning a DisplayObject or Rectangle specifying the bounding box of a child element in the AccessibilityImplementation.	AccessibilityImplementation
		accSelect(operation:uint, childID:uint):void IAccessible method for altering the selection in the component that this AccessibilityImplementation represents.	AccessibilityImplementation
		enableAccessibility():void [static] Enables accessibility in the DropDownListBase class.	DropDownListBaseAccImpl
		get_accDefaultAction(childID:uint):String MSAA method for returning the default action of the component that this AccessibilityImplementation represents or of one of its child elements.	AccessibilityImplementation
		get_accFocus():uint MSAA method for returning the unsigned integer ID of the child element, if any, that has child focus within the component.	AccessibilityImplementation
		get_accName(childID:uint):String MSAA method for returning the name for the component that this AccessibilityImplementation represents or for one of its child elements.	AccessibilityImplementation
		get_accRole(childID:uint):uint MSAA method for returning the system role for the component that this AccessibilityImplementation represents or for one of its child elements.	AccessibilityImplementation
		get_accSelection():Array MSAA method for returning an array containing the IDs of all child elements that are selected.	AccessibilityImplementation
		get_accState(childID:uint):uint IAccessible method for returning the current runtime state of the component that this AccessibilityImplementation represents or of one of its child elements.	AccessibilityImplementation
		get_accValue(childID:uint):String MSAA method for returning the runtime value of the component that this AccessibilityImplementation represents or of one of its child elements.	AccessibilityImplementation
		get_selectionActiveIndex():*	AccessibilityImplementation
		get_selectionAnchorIndex():*	AccessibilityImplementation
		getChildIDArray():Array Returns an array containing the unsigned integer IDs of all child elements in the AccessibilityImplementation.	AccessibilityImplementation
		getFormName(component:UIComponent):String [static] Method for supporting Form Accessibility.	AccImpl
		hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined.	Object
		isAncestorDisabled(component:UIComponent):Boolean [static] Returns true if an ancestor of the component has enabled set to false.	AccImpl
		isLabeledBy(labelBounds:Rectangle):Boolean Returns true or false to indicate whether a text object having a bounding box specified by a x, y, width, and height should be considered a label for the component that this AccessibilityImplementation represents.	AccessibilityImplementation
		isPrototypeOf(theClass:Object):Boolean Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.	Object
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions.	Object
		toString():String Returns the string representation of the specified object.	Object
		valueOf():Object Returns the primitive value of the specified object.	Object

Protected Methods

	Method		Defined By
		eventHandler(event:Event):void Generic event handler.	AccImpl
		getName(childID:uint):String Returns the name of the accessible component.	AccImpl
		getState(childID:uint):uint Utility method to determine state of the accessible component.	AccImpl

Constructor Detail