ListCollectionView

Pacchetto	mx.collections
Classe	public class ListCollectionView
Ereditarietà	ListCollectionView Proxy
Implementa	ICollectionView, IList, IMXMLObject
Sottoclassi	ArrayCollection, XMLListCollection

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

The ListCollectionView class adds the properties and methods of the ICollectionView interface to an object that conforms to the IList interface. As a result, you can pass an object of this class to anything that requires an IList or ICollectionView.

This class also lets you use [ ] array notation to access the getItemAt() and setItemAt() methods. If you use code such as myListCollectionView[index] Flex calls the myListCollectionView object's getItemAt() or setItemAt() method.

Sintassi MXML expanded

Nascondi sintassi MXML

The <mx:ListCollectionView> has the following attributes, which all of its subclasses inherit:

  <mx:ListCollectionView
  Properties
  filterFunction="null"
  list="null"
  sort="null"
  Events
  collectionChange="No default"
  />

Proprietà pubbliche

	Proprietà		Definito da
		filterFunction : Function A function that the view will use to eliminate items that do not match the function's criteria.	ListCollectionView
		length : int [sola lettura] The number of items in this view.	ListCollectionView
		list : IList The IList that this collection view wraps.	ListCollectionView
		sort : ISort The ISort that will be applied to the ICollectionView.	ListCollectionView

Proprietà protette

	Proprietà		Definito da
		localIndex : Array When the view is sorted or filtered the localIndex property contains an array of items in the sorted or filtered (ordered, reduced) view, in the sorted order.	ListCollectionView

Metodi pubblici

	Metodo		Definito da
		ListCollectionView(list:IList = null) The ListCollectionView constructor.	ListCollectionView
		addAll(addList:IList):void Adds a list of items to the current list, placing them at the end of the list in the order they are passed.	ListCollectionView
		addAllAt(addList:IList, index:int):void Adds a list of items to the current list, placing them at the position index passed in to the function.	ListCollectionView
		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.	ListCollectionView
		addItem(item:Object):void Adds the specified item to the end of the list.	ListCollectionView
		addItemAt(item:Object, index:int):void Adds the item at the specified index.	ListCollectionView
		contains(item:Object):Boolean Returns whether the view contains the specified object.	ListCollectionView
		createCursor():IViewCursor Creates a new IViewCursor that works with this view.	ListCollectionView
		disableAutoUpdate():void Prevents changes to the collection itself and items within the collection from being dispatched by the view.	ListCollectionView
		dispatchEvent(event:Event):Boolean Dispatches an event into the event flow.	ListCollectionView
		enableAutoUpdate():void Enables auto-updating.	ListCollectionView
		getItemAt(index:int, prefetch:int = 0):Object Gets the item at the specified index.	ListCollectionView
		getItemIndex(item:Object):int Returns the index of the item if it is in the list such that getItemAt(index) == item.	ListCollectionView
		hasEventListener(type:String):Boolean Checks whether the EventDispatcher object has any listeners registered for a specific type of event.	ListCollectionView
		initialized(document:Object, id:String):void Called automatically by the MXML compiler when the ListCollectionView is created using an MXML tag.	ListCollectionView
		itemUpdated(item:Object, property:Object = null, oldValue:Object = null, newValue:Object = null):void Notifies the view that an item has been updated.	ListCollectionView
		refresh():Boolean Applies the sort and filter to the view.	ListCollectionView
		removeAll():void Remove all items from the list.	ListCollectionView
		removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes a listener from the EventDispatcher object.	ListCollectionView
		removeItemAt(index:int):Object Removes the item at the specified index and returns it.	ListCollectionView
		setItemAt(item:Object, index:int):Object Places the item at the specified index.	ListCollectionView
		toArray():Array Returns an Array that is populated in the same order as the IList implementation.	ListCollectionView
		toString():String Prints the contents of this view to a string and returns it.	ListCollectionView
		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.	ListCollectionView

Eventi

Fate clic per visualizzare altre informazioni sugli eventi

	Evento		Riepilogo	Definito da
		collectionChange	Dispatched when the ICollectionView has been updated in some way.	ListCollectionView

Descrizione delle proprietà

filterFunction

proprietà

filterFunction:Function

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

A function that the view will use to eliminate items that do not match the function's criteria. A filterFunction is expected to have the following signature:

f(item:Object):Boolean

where the return value is true if the specified item should remain in the view.

If a filter is unsupported, Flex throws an error when accessing this property. You must call refresh() after setting the filterFunction property for the view to update.

Note: The Flex implementations of ICollectionView retrieve all items from a remote location before executing the filter function. If you use paging, apply the filter to the remote collection before you retrieve the data.

Questa proprietà può essere utilizzata come origine per l’associazione di dati. Quando questa proprietà viene modificata, invia l’evento filterFunctionChanged .

Implementazione
public function get filterFunction():Function
public function set filterFunction(value:Function):void

Elementi API correlati

refresh()

length

proprietà

length:int [sola lettura]

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

The number of items in this view. 0 means no items, while -1 means that the length is unknown.

Questa proprietà può essere utilizzata come origine per l’associazione di dati. Quando questa proprietà viene modificata, invia l’evento collectionChange .

Implementazione
public function get length():int

list

proprietà

list:IList

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

The IList that this collection view wraps.

Questa proprietà può essere utilizzata come origine per l’associazione di dati. Quando questa proprietà viene modificata, invia l’evento listChanged .

Implementazione
public function get list():IList
public function set list(value:IList):void

localIndex

proprietà

protected var localIndex:Array

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

When the view is sorted or filtered the localIndex property contains an array of items in the sorted or filtered (ordered, reduced) view, in the sorted order. The ListCollectionView class uses this property to access the items in the view. The localIndex property should never contain anything that is not in the source, but may not have everything in the source. This property is null when there is no sort.

sort

proprietà

sort:ISort

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

The ISort that will be applied to the ICollectionView. Setting the sort does not automatically refresh the view, so you must call the refresh() method after setting this property. If sort is unsupported an error will be thrown when accessing this property.

Note: The Flex implementations of ICollectionView retrieve all items from a remote location before executing a sort. If you use paging with a sorted list, apply the sort to the remote collection before you retrieve the data.

Questa proprietà può essere utilizzata come origine per l’associazione di dati. Quando questa proprietà viene modificata, invia l’evento sortChanged .

Implementazione
public function get sort():ISort
public function set sort(value:ISort):void

Elementi API correlati

refresh()

Descrizione della funzione di costruzione

()

Funzione di costruzione

public function ListCollectionView(list:IList = null)

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

The ListCollectionView constructor.

Parametri

list:IList (default = null) — the IList this ListCollectionView is meant to wrap.

Descrizione dei metodi

addAll

()

metodo

public function addAll(addList:IList):void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Adds a list of items to the current list, placing them at the end of the list in the order they are passed.

Parametri

addList:IList — The list of items to add to the current list

addAllAt

()

metodo

public function addAllAt(addList:IList, index:int):void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Adds a list of items to the current list, placing them at the position index passed in to the function. The items are placed at the index location and placed in the order they are recieved.

Parametri

	`addList:IList` — The list of items to add to the current list

	`index:int` — The location of the current list to place the new items.

Genera

RangeError — if index is less than 0 or greater than the length of the list.

addEventListener

()

metodo

 public function addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event. You can register event listeners on all nodes in the display list for a specific type of event, phase, and priority.

After you successfully register an event listener, you cannot change its priority through additional calls to addEventListener(). To change a listener's priority, you must first call removeEventListener(). Then you can register the listener again with the new priority level.

After the listener is registered, subsequent calls to addEventListener() with a different value for either type or useCapture result in the creation of a separate listener registration. For example, if you first register a listener with useCapture set to true, it listens only during the capture phase. If you call addEventListener() again using the same listener object, but with useCapture set to false, you have two separate listeners: one that listens during the capture phase, and another that listens during the target and bubbling phases.

You cannot register an event listener for only the target phase or the bubbling phase. Those phases are coupled during registration because bubbling applies only to the ancestors of the target node.

When you no longer need an event listener, remove it by calling EventDispatcher.removeEventListener(); otherwise, memory problems might result. Objects with registered event listeners are not automatically removed from memory because the garbage collector does not remove objects that still have references.

Copying an EventDispatcher instance does not copy the event listeners attached to it. (If your newly created node needs an event listener, you must attach the listener after creating the node.) However, if you move an EventDispatcher instance, the event listeners attached to it move along with it.

If the event listener is being registered on a node while an event is also being processed on this node, the event listener is not triggered during the current phase but may be triggered during a later phase in the event flow, such as the bubbling phase.

If an event listener is removed from a node while an event is being processed on the node, it is still triggered by the current actions. After it is removed, the event listener is never invoked again (unless it is registered again for future processing).

Parametri

	`type:String` — The type of event.

	`listener:Function` — The listener function that processes the event. This function must accept an event object as its only parameter and must return nothing, as this example shows: `function(evt:Event):void` The function can have any name.

	`useCapture:Boolean` (default = `false`) — Determines whether the listener works in the capture phase or the target and bubbling phases. If `useCapture` is set to `true`, the listener processes the event only during the capture phase and not in the target or bubbling phase. If `useCapture` is `false`, the listener processes the event only during the target or bubbling phase. To listen for the event in all three phases, call `addEventListener()` twice, once with `useCapture` set to `true`, then again with `useCapture` set to `false`.

	`priority:int` (default = `0`) — The priority level of the event listener. Priorities are designated by a 32-bit integer. The higher the number, the higher the priority. All listeners with priority n are processed before listeners of priority n-1. If two or more listeners share the same priority, they are processed in the order in which they were added. The default priority is 0.

	`useWeakReference:Boolean` (default = `false`) — Determines whether the reference to the listener is strong or weak. A strong reference (the default) prevents your listener from being garbage-collected. A weak reference does not. Class-level member functions are not subject to garbage collection, so you can set `useWeakReference` to `true` for class-level member functions without subjecting them to garbage collection. If you set `useWeakReference` to `true` for a listener that is a nested inner function, the function will be garbge-collected and no longer persistent. If you create references to the inner function (save it in another variable) then it is not garbage-collected and stays persistent.

addItem

()

metodo

public function addItem(item:Object):void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Adds the specified item to the end of the list. Equivalent to addItemAt(item, length).

Parametri

item:Object — The item to add.

addItemAt

()

metodo

public function addItemAt(item:Object, index:int):void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Adds the item at the specified index. The index of any item greater than the index of the added item is increased by one. If the the specified index is less than zero or greater than the length of the list, a RangeError is thrown.

Parametri

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

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

contains

()

metodo

public function contains(item:Object):Boolean

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Returns whether the view contains the specified object. Unlike the IViewCursor.findxxx methods, this search is succesful only if it finds an item that exactly matches the parameter. If the view has a filter applied to it this method may return false even if the underlying collection does contain the item.

Parametri

item:Object — The object to look for.

Restituisce

Boolean — true if the ICollectionView, after applying any filter, contains the item; false otherwise.

Elementi API correlati

enableAutoUpdate()
mx.events.CollectionEvent

createCursor

()

metodo

public function createCursor():IViewCursor

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Creates a new IViewCursor that works with this view.

Restituisce

IViewCursor — A new IViewCursor implementation.

disableAutoUpdate

()

metodo

public function disableAutoUpdate():void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Prevents changes to the collection itself and items within the collection from being dispatched by the view. Also prevents the view from updating the positions of items if the positions change in the collection. The changes will be queued and dispatched appropriately after enableAutoUpdate is called. If more events than updates to a single item occur, the view may end up resetting. The disableAutoUpdate method acts cumulatively; the same number of calls to enableAutoUpdate are required for the view to dispatch events and refresh. Note that disableAutoUpdate only affects the individual view; edits may be detected on an individual basis by other views.

Elementi API correlati

mx.collections.ICollectionView.enableAutoUpdate()
mx.events.CollectionEvent

dispatchEvent

()

metodo

public function dispatchEvent(event:Event):Boolean

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Dispatches an event into the event flow. The event target is the EventDispatcher object upon which dispatchEvent() is called.

Parametri

event:Event — The event object dispatched into the event flow.

Restituisce

Boolean — A value of true unless preventDefault() is called on the event, in which case it returns false.

enableAutoUpdate

()

metodo

public function enableAutoUpdate():void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Enables auto-updating. See disableAutoUpdate for more information.

Elementi API correlati

mx.collections.ICollectionView.disableAutoUpdate()

getItemAt

()

metodo

public function getItemAt(index:int, prefetch:int = 0):Object

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Gets the item at the specified index.

Parametri

	`index:int` — The index in the list 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.

Restituisce

Object — The item at that index, or null if there is none.

getItemIndex

()

metodo

public function getItemIndex(item:Object):int

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Returns the index of the item if it is in the list such that getItemAt(index) == item.

Note: unlike IViewCursor.findxxx() methods, The getItemIndex() method cannot take a parameter with only a subset of the fields in the item being serched for; this method always searches for an item that exactly matches the input parameter.

Parametri

item:Object — The item to find.

Restituisce

int — The index of the item, or -1 if the item is not in the list.

hasEventListener

()

metodo

public function hasEventListener(type:String):Boolean

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Checks whether the EventDispatcher object has any listeners registered for a specific type of event. This allows you to determine where an EventDispatcher object has altered handling of an event type in the event flow hierarchy. To determine whether a specific event type will actually trigger an event listener, use IEventDispatcher.willTrigger().

The difference between hasEventListener() and willTrigger() is that hasEventListener() examines only the object to which it belongs, whereas willTrigger() examines the entire event flow for the event specified by the type parameter.

Parametri

type:String — The type of event.

Restituisce

Boolean — A value of true if a listener of the specified type is registered; false otherwise.

initialized

()

metodo

public function initialized(document:Object, id:String):void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Called automatically by the MXML compiler when the ListCollectionView is created using an MXML tag. If you create the ListCollectionView through ActionScript, you must call this method passing in the MXML document and null for the id.

Parametri

	`document:Object` — The MXML document containing this ListCollectionView.

	`id:String` — Ignored.

itemUpdated

()

metodo

public function itemUpdated(item:Object, property:Object = null, oldValue:Object = null, newValue:Object = null):void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Notifies the view that an item has been updated. This method is useful if the contents of the view do not implement IPropertyChangeNotifier. If the call to this method includes a property parameter, the view may be able to optimize its notification mechanism. Otherwise it may choose to simply refresh the whole view.

Parametri

	`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.)

Elementi API correlati

mx.events.CollectionEvent
mx.core.IPropertyChangeNotifier
mx.events.PropertyChangeEvent

refresh

()

metodo

public function refresh():Boolean

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Applies the sort and filter to the view. The ICollectionView does not detect changes to a sort or filter automatically, so you must call the refresh() method to update the view after setting the sort or filterFunction property. If your ICollectionView implementation also implements the IMXMLObject interface, you should to call the refresh() method from your initialized() method.

Returns true if the refresh was successful and false if the sort is not yet complete (e.g., items are still pending). A client of the view should wait for a CollectionEvent event with the CollectionEventKind.REFRESH kind property to ensure that the refresh() operation is complete.

Restituisce

Boolean — true if the refresh() was complete, false if the refresh() is incomplete.

removeAll

()

metodo

public function removeAll():void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Remove all items from the list.

removeEventListener

()

metodo

public function removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Removes a listener from the EventDispatcher object. If there is no matching listener registered with the EventDispatcher object, a call to this method has no effect.

Parametri

	`type:String` — The type of event.

	`listener:Function` — The listener object to remove.

	`useCapture:Boolean` (default = `false`) — Specifies whether the listener was registered for the capture phase or the target and bubbling phases. If the listener was registered for both the capture phase and the target and bubbling phases, two calls to `removeEventListener()` are required to remove both: one call with `useCapture` set to `true`, and another call with `useCapture` set to `false`.

removeItemAt

()

metodo

public function removeItemAt(index:int):Object

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Removes the item at the specified index and returns it. Any items that were after this index are now one index earlier.

Parametri

index:int — The index from which to remove the item.

Restituisce

Object — The item that was removed.

setItemAt

()

metodo

public function setItemAt(item:Object, index:int):Object

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Places the item at the specified index. If an item was already at that index the new item will replace it and it will be returned.

Parametri

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

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

Restituisce

Object — The item that was replaced, or null if none.

toArray

()

metodo

public function toArray():Array

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Returns an Array that is populated in the same order as the IList implementation. This method can throw an ItemPendingError.

Restituisce

Array — The array.

toString

()

metodo

public function toString():String

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Prints the contents of this view to a string and returns it.

Restituisce

String — The contents of this view, in string form.

willTrigger

()

metodo

public function willTrigger(type:String):Boolean

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type. This method returns true if an event listener is triggered during any phase of the event flow when an event of the specified type is dispatched to this EventDispatcher object or any of its descendants.

Parametri

type:String — The type of event.

Restituisce

Boolean — A value of true if a listener of the specified type will be triggered; false otherwise.

Descrizione degli eventi

collectionChange

Evento

Tipo di oggetto evento: mx.events.CollectionEvent
proprietà CollectionEvent.type = mx.events.CollectionEvent.COLLECTION_CHANGE

Versione linguaggio:

ActionScript 3.0

Versione prodotto:

Flex 3

Versioni runtime:

Flash Player 9, AIR 1.1

Dispatched when the ICollectionView has been updated in some way.

The CollectionEvent.COLLECTION_CHANGE constant defines the value of the type property of the event object for an event that is dispatched when a collection has changed.

The properties of the event object have the following values. Not all properties are meaningful for all kinds of events. See the detailed property descriptions for more information.

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

Note legali | Informativa sulla privacy online

ListCollectionView - AS3 Flex

Classi x

filterFunction

length

list

localIndex

sort