public interface IViewCursor extends flash.events.IEventDispatcher
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
Defines the interface for enumerating a collection view bi-directionally.
This cursor provides find, seek, and bookmarking capabilities along
with the modification methods insert and remove.
When a cursor is first retrieved from a view, (typically by the ICollectionView
createCursor() method) the value of the
current property should be the first
item in the view, unless the view is empty.
Dispatched whenever the cursor position is updated.
IViewCursor
Property Detail
afterLast
property
afterLast:Boolean [read-only]
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
If the cursor is located after the last item in the view,
this property is true .
If the ICollectionView is empty (length == 0),
this property is true.
This property can be used as the source for data binding.
Implementation public function get afterLast():Boolean
beforeFirst
property
beforeFirst:Boolean [read-only]
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
If the cursor is located before the first item in the view,
this property is true.
If the ICollectionView is empty (length == 0),
this property is true.
This property can be used as the source for data binding.
Implementation public function get beforeFirst():Boolean
Provides access to a bookmark that corresponds to the item
returned by the current property.
The bookmark can be used to move the cursor
to a previously visited item, or to a position relative to that item.
(See the seek() method for more information.)
This property can be used as the source for data binding.
Implementation public function get bookmark():CursorBookmark
Provides access the object at the location
in the source collection referenced by this cursor.
If the cursor is beyond the ends of the collection
(beforeFirst, afterLast)
this will return null.
This property can be used as the source for data binding.
Implementation public function get current():Object
Finds an item with the specified properties within the collection
and positions the cursor to that item.
If the item cannot be found, the cursor location does not change.
The findAny() method can only be called on sorted views;
if the view isn't sorted, a CursorError is thrown.
If the associated collection is remote, and not all of the items
have been cached locally, this method begins an asynchronous fetch
from the remote collection. If one is already in progress, this method
waits for it to complete before making another fetch request.
If multiple items can match the search criteria then the item found
is non-deterministic.
If it is important to find the first or last occurrence of an item
in a non-unique index, use the findFirst() or
findLast() method.
If the data is not local and an asynchronous operation must be
performed, an ItemPendingError is thrown.
Parameters
values:Object — The search criteria. The values in the Object must be configured as name-value pairs,
as in an associative array (or be the actual object to search for). The values of the names specified must match properties
specified in the sort. For example, if properties x, y, and
z are in the current sort, the values specified should be
{x: x-value, y: y-value, z: z-value}.
Returns
Boolean — When all of the data is local this method returns
true if the item can be found and false
otherwise.
Finds the first item with the specified properties within the collection
and positions the cursor to that item.
If the item cannot be found, no cursor location does not change.
The findFirst() method can only be called on sorted views;
if the view isn't sorted, a CursorError is thrown.
If the associated collection is remote, and not all of the items
have been cached locally, this method begins an asynchronous fetch
from the remote collection. If one is already in progress, this method
waits for it to complete before making another fetch request.
If it is not important to find the first occurrence of an item
in a non-unique index, use findAny(), which may be
a little faster than the findFirst() method.
If the data is not local and an asynchronous operation must be
performed, an ItemPendingError is thrown.
Parameters
values:Object — The search criteria. The values in the Object must be configured as name-value pairs,
as in an associative array (or be the actual object to search for). The values of the names
specified must match properties specified in the sort. For example, if properties x,
y, and z are in the current sort, the values specified should be
{x: x-value, y: y-value, z: z-value}.
Returns
Boolean — When all of the data is local this method returns
true if the item can be found and false
otherwise.
Finds the last item with the specified properties within the collection
and positions the cursor on that item.
If the item cannot be found, the cursor location does not chanage.
The findLast() method can only be called on sorted views;
if the view isn't sorted, a CursorError is thrown.
If the associated collection is remote, and not all of the items
have been cached locally, this method begins an asynchronous fetch
from the remote collection. If one is already in progress, this method
waits for it to complete before making another fetch request.
If it is not important to find the last occurrence of an item
in a non-unique index, use the findAny() method, which
may be a little faster.
If the data is not local and an asynchronous operation must be
performed, an ItemPendingError is thrown.
Parameters
values:Object — The search criteria. The values in the Object must be configured as name-value pairs,
as in an associative array (or be the actual object to search for). The values of the names
specified must match properties specified in the sort. For example, if properties x,
y, and z are in the current sort, the values specified should be
{x: x-value, y: y-value, z: z-value}.
Returns
Boolean — When all of the data is local this method returns
true if the item can be found and false
otherwise.
Inserts the specified item before the cursor's current position.
If the cursor is afterLast,
the insertion occurs at the end of the view.
If the cursor is beforeFirst on a non-empty view,
an error is thrown.
Parameters
item:Object — The item to insert before the cursor's current position.
moveNext
()
method
public function moveNext():Boolean
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
Moves the cursor to the next item within the collection.
On success the current property is updated
to reference the object at this new location.
Returns true if the resulting current
property is valid, or false if not
(the property value is afterLast).
If the data is not local and an asynchronous operation must be performed,
an ItemPendingError is thrown.
See the ItemPendingError documentation and the collections
documentation for more information on using the ItemPendingError.
Returns
Boolean — true if still in the list,
false if the current value initially was
or now is afterLast.
var myArrayCollection:ICollectionView = new ArrayCollection([ "Bobby", "Mark", "Trevor", "Jacey", "Tyler" ]);
var cursor:IViewCursor = myArrayCollection.createCursor();
while (!cursor.afterLast)
{
trace(cursor.current);
cursor.moveNext();
}
movePrevious
()
method
public function movePrevious():Boolean
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
Moves the cursor to the previous item within the collection.
On success the current property is updated
to reference the object at this new location.
Returns true if the resulting current
property is valid, or false if not
(the property value is beforeFirst).
If the data is not local and an asynchronous operation must be performed,
an ItemPendingError is thrown.
See the ItemPendingError documentation and the collections
documentation for more information on using the ItemPendingError.
Returns
Boolean — true if still in the list,
false if the current value initially was or
now is beforeFirst.
For example:
var myArrayCollection:ICollectionView = new ArrayCollection([ "Bobby", "Mark", "Trevor", "Jacey", "Tyler" ]);
var cursor:IViewCursor = myArrayCollection.createCursor();
cursor.seek(CursorBookmark.last);
while (!cursor.beforeFirst)
{
trace(current);
cursor.movePrevious();
}
Removes the current item and returns it.
If the cursor location is beforeFirst or
afterLast, throws a CursorError.
If you remove any item other than the last item,
the cursor moves to the next item. If you remove the last item, the
cursor is at the AFTER_LAST bookmark.
If the item after the removed item is not local and an asynchronous
operation must be performed, an ItemPendingError is thrown.
See the ItemPendingError documentation and the collections
documentation for more information on using the ItemPendingError.
public function seek(bookmark:CursorBookmark, offset:int = 0, prefetch:int = 0):void
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
Moves the cursor to a location at an offset from the specified
bookmark.
The offset can be negative, in which case the cursor is positioned
an offset number of items prior to the specified bookmark.
If the associated collection is remote, and not all of the items
have been cached locally, this method begins an asynchronous fetch
from the remote collection.
If the data is not local and an asynchronous operation
must be performed, an ItemPendingError is thrown.
See the ItemPendingError documentation and the collections
documentation for more information on using the ItemPendingError.
Parameters
bookmark:CursorBookmark — CursorBookmark reference to marker
information that allows repositioning to a specific location.
You can set this parameter to value returned from the
bookmark property, or to one of the following constant
bookmark values:
CursorBookmark.FIRST -
Seek from the start (first element) of the collection
CursorBookmark.CURRENT -
Seek from the current position in the collection
CursorBookmark.LAST -
Seek from the end (last element) of the collection
offset:int (default = 0) — Indicates how far from the specified bookmark to seek.
If the specified number is negative, the cursor attempts to
move prior to the specified bookmark.
If the offset specified is beyond the end of the collection,
the cursor is be positioned off the end, to the
beforeFirst or afterLast location.
prefetch:int (default = 0) — Used for remote data. Indicates an intent to iterate
in a specific direction once the seek operation completes.
This reduces the number of required network round trips during a seek.
If the iteration direction is known at the time of the request,
the appropriate amount of data can be returned ahead of the request
to iterate it.
Dispatched whenever the cursor position is updated.
The FlexEvent.CURSOR_UPDATE constant defines the value of the
type property of the event object for a cursorUpdate event.
The properties of the event object have the following values:
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.
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.
