AsyncListView

(Preview)

Package	mx.collections
Class	public class AsyncListView
Inheritance	AsyncListView OnDemandEventDispatcher Object
Implements	IList

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The AsyncListView class is an implementation of the IList interface that handles ItemPendingErrors errors thrown by the getItemAt(), removeItemAt(), and toArray() methods.

The getItemAt() method handles ItemPendingErrors by returning a provisional "pending" item until the underlying request succeeds or fails. The provisional item is produced by calling the function specified by the createPendingItemFunction property. . If the request succeeds, the actual item replaces the provisional one. If it fails, the provisional item is replaced with the item returned by calling the function specified by the createFailedItemFunction property.

This class delegates the IList methods and properties to its list. If a list isn't specified, methods that mutate the collection are no-ops, and methods that query the collection return an empty value, such as null or zero as appropriate.

This class is intended to be used with Spark components based on DataGroup, such as List and ComboBox. The Spark classes do not provide intrinsic support for ItemPendingError handling.

AsyncListView does not support re-insertion of pending or failed items. Once a failed or pending item is removed, its connection to a pending request for data is lost. Using drag and drop to move a pending item in an ASyncListView, or sorting an ASyncListView that contains pending or failed items, is not supported because these operations remove and then re-insert list items.

MXML Syntax expanded

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The <mx:AsyncListView> tag inherits all the attributes of its superclass, and adds the following attributes:

  <mx:AsyncListView
  Properties
    createFailedItemFunction="null"
    createPendingItemFunction="null"
    list="null"
  />

Public Properties

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	Property		Defined By
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		createFailedItemFunction : Function A callback function used to create a substitute item when a request which had caused an ItemPendingError to be thrown, subsequently fails.	AsyncListView
		createPendingItemFunction : Function A callback function used to create a provisional item when the initial request causes an ItemPendingError to be thrown.	AsyncListView
		length : int [read-only] The number of items in this collection.	AsyncListView
		list : IList The IList object that this collection wraps.	AsyncListView

Public Methods

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	Method		Defined By
		AsyncListView(list:IList = null) Constructor.	AsyncListView
		addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event.	OnDemandEventDispatcher
		addItem(item:Object):void Adds the specified item to the end of the list.	AsyncListView
		addItemAt(item:Object, index:int):void Adds the item at the specified index.	AsyncListView
		dispatchEvent(event:Event):Boolean Dispatches an event into the event flow.	OnDemandEventDispatcher
		getItemAt(index:int, prefetch:int = 0):Object Returns the value of list.getItemAt(index).	AsyncListView
		getItemIndex(item:Object):int Returns the index of the item if it is in the list such that getItemAt(index) == item.	AsyncListView
		hasEventListener(type:String):Boolean Checks whether the EventDispatcher object has any listeners registered for a specific type of event.	OnDemandEventDispatcher
		hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined.	Object
		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
		itemUpdated(item:Object, property:Object = null, oldValue:Object = null, newValue:Object = null):void Notifies the view that an item has been updated.	AsyncListView
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		removeAll():void Removes all items from the list.	AsyncListView
		removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes a listener from the EventDispatcher object.	OnDemandEventDispatcher
		removeItemAt(index:int):Object Removes the actual or pending item at the specified index and returns it.	AsyncListView
		setItemAt(item:Object, index:int):Object Places the item at the specified index.	AsyncListView
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		toArray():Array Returns an array with the same elements as this AsyncListView.	AsyncListView
		toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions.	Object
		toString():String Returns a string that contains the list's length and the number of pending item requests.	AsyncListView
		valueOf():Object Returns the primitive value of the specified object.	Object
		willTrigger(type:String):Boolean Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.	OnDemandEventDispatcher

Events

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	Event		Summary	Defined By
		collectionChange	Dispatched when the list's length has changed or when a list element is replaced.	AsyncListView

Property Detail

Constructor Detail

Method Detail

Event Detail

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	`item:Object` — The item within the view that was updated.

	`property:Object` (default = `null`) — The name of the property that was updated.

	`oldValue:Object` (default = `null`) — The old value of that property. (If property was null, this can be the old value of the item.)

	`newValue:Object` (default = `null`) — The new value of that property. (If property was null, there's no need to specify this as the item is assumed to be the new value.)

Property	Value
`bubbles`	false
`cancelable`	false
`currentTarget`	The Object that defines the event listener that handles the event. For example, if you use `myButton.addEventListener()` to register an event listener, myButton is the value of the `currentTarget`.
`items`	An Array of objects with information about the items affected by the event. The contents of this field depend on the event kind; for details see the `items` property
`kind`	The kind of event. The valid values are defined in the CollectionEventKind class as constants.
`location`	Location within the target collection of the item(s) specified in the `items` property.
`oldLocation`	the previous location in the collection of the item specified in the `items` property.
`target`	The Object that dispatched the event; it is not always the Object listening for the event. Use the `currentTarget` property to always access the Object listening for the event.
`type`	CollectionEvent.COLLECTION_CHANGE

AsyncListView - AS3 Flex

Packagesx

Language Elements

Appendixes

Package mx.collections

createFailedItemFunction

createPendingItemFunction

length

list

addItem

addItemAt

getItemAt

getItemIndex

itemUpdated

removeAll

removeItemAt

setItemAt

toArray

toString

collectionChange

	`item:Object` — The item to place at the index.

	`index:int` — The index at which to place the item.

	`index:int` — The list index from which to retrieve the item.

	`prefetch:int` (default = `0`) — An `int` indicating both the direction and number of items to fetch during the request if the item is not local.

	`item:Object` — The new item to be placed at the specified index.

	`index:int` — The index at which to place the item.