Package | spark.collections |
Class | public class Sort |
Inheritance | Sort AdvancedStyleClient EventDispatcher Object |
Implements | ISort |
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 2.5 |
ICollectionView
interface or class that
implements the interface). After you assign a Sort
instance to the view's
sort
property, you must call the view's
refresh()
method to apply the sort criteria.
Typically the sort is defined for collections of complex items, that is collections in which the sort is performed on one or more properties of the objects in the collection. The following example shows this use:
var col:ICollectionView = new ArrayCollection();
// In the real world, the collection would have more than one item.
col.addItem({first:"Anders", last:"Dickerson"});
// Create the Sort instance.
var sort:ISort = new Sort();
// Set the sort field; sort on the last name first, first name second.
var sortfieldLastName:ISortField = new SortField("last",true);
var sortfieldFirstName:ISortField = new SortField("first",true);
// Set the locale style to "en-US" to cause the strings
// to be ordered according to the rules for English as used in the USA.
sortfieldLastName.setStyle("locale","en-US");
sortfieldFirstName.setStyle("locale","en-US");
sort.fields = [sortfieldLastName, sortfieldFirstName];
// Assign the Sort object to the view.
col.sort = sort;
// Apply the sort to the collection.
col.refresh();
There are situations in which the collection contains simple items,
like String
, Date
, Boolean
, etc.
In this case, apply the sort to the simple type directly.
When constructing a sort for simple items, use a single sort field,
and specify a null
name
(first) parameter
in the SortField object constructor.
For example:
import mx.collections.ArrayCollection;
import spark.collections.Sort;
import spark.collections.SortField;
var col:ICollectionView = new ArrayCollection();
col.addItem("California");
col.addItem("Arizona");
var sort:Sort = new Sort();
// There is only one sort field, so use a null
// first parameter.
var sortfield:SortField = new SortField("null",true);
// Set the locale style to "en-US" to set the language for the sort.
sortfield.setStyle("locale","en-US");
sort.fields = [sortfield];
col.sort = sort;
col.refresh();
The Flex implementations of the ICollectionView
interface
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.
The default comparison provided by the SortField
class
provides correct language specific
sorting for strings. The language is selected by the setting the locale
style on an instance of the class in one of the following ways:
- By using the class in an MXML declaration and inheriting the locale from the document that contains the declaration. Example:
<fx:Declarations> <s:SortField id="sf" /> </fx:Declarations>
<fx:Declarations> <s:SortField id="sf_SimplifiedChinese" locale="zh-Hans-CN" /> </fx:Declarations>
setStyle
method,
e.g. sf.setStyle("locale", "zh-Hans-CN")
UIComponent
by calling the
UIComponent's addStyleClient()
method.
The <s:Sort>
tag has the following attributes:
<s:Sort Properties compareFunction="Internal compare function" fields="null" unique="false | true" />
In case items have inconsistent data types or items have complex data types, use of default built-in compare functions is not desired. Inconsistent sort result may occur in such cases. To avoid such problem, provide custom compare function and/or make item types consistent.
Default MXML Propertyfields
More examples
Related API Elements
Property | Defined By | ||
---|---|---|---|
className : String [read-only]
The name of the component class. | AdvancedStyleClient | ||
compareFunction : Function
The method used to compare items when sorting. | Sort | ||
constructor : Object
A reference to the class object or constructor function for a given object instance. | Object | ||
fields : Array
An Array of ISortField objects that specifies the fields to compare. | Sort | ||
id : String
The identity of the component. | AdvancedStyleClient | ||
inheritingStyles : Object
An object containing the inheritable styles for this non-visual
style client instance. | AdvancedStyleClient | ||
moduleFactory : IFlexModuleFactory
A module factory is used as context for
finding the style manager that controls the styles for this
non-visual style client instance. | AdvancedStyleClient | ||
nonInheritingStyles : Object
The beginning of this component's chain of non-inheriting styles. | AdvancedStyleClient | ||
styleDeclaration : CSSStyleDeclaration
The style declaration that holds the inline styles declared by this
object. | AdvancedStyleClient | ||
styleManager : IStyleManager2 [read-only]
Returns the StyleManager instance used by this component. | AdvancedStyleClient | ||
styleName : Object
The source of this object's style values. | AdvancedStyleClient | ||
styleParent : IAdvancedStyleClient
A component's parent is used to evaluate descendant selectors. | AdvancedStyleClient | ||
unique : Boolean
Indicates if the sort should be unique. | Sort |
Method | Defined By | ||
---|---|---|---|
Sort()
Constructor. | Sort | ||
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. | EventDispatcher | ||
Deletes a style property from this component instance. | AdvancedStyleClient | ||
Dispatches an event into the event flow. | EventDispatcher | ||
findItem(items:Array, values:Object, mode:String, returnInsertionIndex:Boolean = false, compareFunction:Function = null):int
Finds the specified object within the specified array (or the insertion
point if asked for), returning the index if found or -1 if not. | Sort | ||
Returns an Array of CSSStyleDeclaration objects for the type selector
that applies to this component, or null if none exist. | AdvancedStyleClient | ||
Gets a style property that has been set anywhere in this
component's style lookup chain. | AdvancedStyleClient | ||
Returns true if currentCSSState is not null. | AdvancedStyleClient | ||
Checks whether the EventDispatcher object has any listeners registered for a specific type
of event. | EventDispatcher | ||
Indicates whether an object has a specified property defined. | Object | ||
The initialized method is called when this class or a class that
extends this class is used in an MXML declaration. | AdvancedStyleClient | ||
Indicates whether an instance of the Object class is in the prototype chain of the object specified
as the parameter. | Object | ||
Returns true if cssState matches currentCSSState. | AdvancedStyleClient | ||
Determines whether this instance is the same as, or is a subclass of,
the given type. | AdvancedStyleClient | ||
Propagates style changes to the children of this style client
instance. | AdvancedStyleClient | ||
Return whether the specified property is used to control the sort. | Sort | ||
Indicates whether the specified property exists and is enumerable. | Object | ||
Sets up the internal style cache values so that the
getStyle()
method functions. | AdvancedStyleClient | ||
Registers the EffectManager as one of the event listeners
for each effect event. | AdvancedStyleClient | ||
Removes a listener from the EventDispatcher object. | EventDispatcher | ||
Goes through the fields array and calls
reverse() on each of the ISortField objects in
the array. | Sort | ||
Sets the availability of a dynamic property for loop operations. | Object | ||
Sets a style property on this component instance. | AdvancedStyleClient | ||
Apply the current sort to the specified array (not a copy). | Sort | ||
Detects changes to style properties. | AdvancedStyleClient | ||
Flex calls the stylesInitialized() method when
the styles for a component are first initialized. | AdvancedStyleClient | ||
Returns the string representation of this object, formatted according to locale-specific conventions. | Object | ||
Returns the string representation of the specified object. | Object | ||
Returns the primitive value of the specified object. | Object | ||
Checks whether an event listener is registered with this EventDispatcher object or any of
its ancestors for the specified event type. | EventDispatcher |
Styles are either common or associated with a specific theme. If the style is common, it can be used with any theme. If a style is associated with a specific theme, it can only be used if your application uses that theme.
Style | Description | Defined By | ||
---|---|---|---|---|
locale | Type: String CSS Inheritance: Yes Language Version: ActionScript 3.0 Product Version: Flex 4.5 Runtime Versions: Flash10.1, AIR 2.5 The locale identifier that specifies the language, region, script and optionally other related tags and keys. The syntax of this identifier must follow the syntax defined by the Unicode Technical Standard #35 (for example, en-US, de-DE, zh-Hans-CN). For browser based apps, the default locale is based on the language settings from the browser. (Note that this is not the browser UI language that is available from Javascript, but rather is the list of preferred locales for web pages that the user has set in the browser preferences.) For AIR applications, the default UI locale is based on the user's system preferences. Learn more | Sort |
Constant | Defined By | ||
---|---|---|---|
ANY_INDEX_MODE : String = "any" [static]
When executing a find return the index any matching item. | Sort | ||
FIRST_INDEX_MODE : String = "first" [static]
When executing a find return the index for the first matching item. | Sort | ||
LAST_INDEX_MODE : String = "last" [static]
When executing a find return the index for the last matching item. | Sort |
compareFunction | property |
compareFunction:Function
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 1.5 |
The method used to compare items when sorting.
If you specify this property, Flex ignores any
compareFunction
properties that you specify in the
ISortField
objects that you use in this class.
The compare function must have the following signature:
function [name](a:Object, b:Object, fields:Array = null):int
This function must return the following value:
- -1, if the
Object a
should appear before theObject b
in the sorted sequence - 0, if the
Object a
equals theObject b
- 1, if the
Object a
should appear after theObject b
in the sorted sequence
To return to the internal comparision function, set this value to
null
.
The fields
array specifies the object fields
to compare.
Typically the algorithm will compare properties until the field list is
exhausted or a non-zero value can be returned.
For example:
function myCompare(a:Object, b:Object, fields:Array = null):int
{
var result:int = 0;
var i:int = 0;
var propList:Array = fields ? fields : internalPropList;
var len:int = propList.length;
var propName:String;
while (result == 0 && (i < len))
{
propName = propList[i];
result = compareValues(a[propName], b[propName]);
i++;
}
return result;
}
function compareValues(a:Object, b:Object):int
{
if (a == null && b == null)
return 0;
if (a == null)
return 1;
if (b == null)
return -1;
if (a < b)
return -1;
if (a > b)
return 1;
return 0;
}
The default value is an internal compare function that can perform a string, numeric, or date comparison in ascending or descending order. Specify your own function only if you need a need a custom comparison algorithm. This is normally only the case if a calculated field is used in a display.
Alternatively you can specify separate compare functions for each
sort field by using the ISortField
class
compareFunction
property; This way you can use the default
comparison for some fields and a custom comparison for others.
Implementation
public function get compareFunction():Function
public function set compareFunction(value:Function):void
fields | property |
fields:Array
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 2.5 |
An Array
of ISortField
objects that specifies the fields to compare.
The order of the ISortField objects in the array determines
field priority order when sorting.
The default sort comparator checks the sort fields in array
order until it determinines a sort order for the two
fields being compared.
The default value is null.
This property can be used as the source for data binding. When this property is modified, it dispatches the fieldsChanged
event.
Implementation
public function get fields():Array
public function set fields(value:Array):void
Related API Elements
unique | property |
unique:Boolean
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 1.5 |
Indicates if the sort should be unique.
Unique sorts fail if any value or combined value specified by the
fields listed in the fields property result in an indeterminate or
non-unique sort order; that is, if two or more items have identical
sort field values. An error is thrown if the sort is not unique.
The sorting logic uses this unique
property value only if sort
field(s) are specified explicitly. If no sort fields are specified
explicitly, no error is thrown even when there are identical value
elements.
The default value is false.
Implementation
public function get unique():Boolean
public function set unique(value:Boolean):void
Sort | () | Constructor |
public function Sort()
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 2.5 |
Constructor.
Creates a new Sort with no fields set and no custom comparator.
findItem | () | method |
public function findItem(items:Array, values:Object, mode:String, returnInsertionIndex:Boolean = false, compareFunction:Function = null):int
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 2.5 |
Finds the specified object within the specified array (or the insertion
point if asked for), returning the index if found or -1 if not.
The ListCollectionView
class findxxx()
methods use this method to find the requested item; as a general rule,
it is easier to use these functions, and not findItem()
to find data in ListCollectionView
-based objects.
You call the findItem()
method directly when writing a
class that supports sorting, such as a new ICollectionView
implementation.
The input items array need to be sorted before calling this function.
Otherwise this function will not be able to find the specified value
properly.
Parameters
items:Array — the Array within which to search.
| |||||||
values:Object — Object containing the properties to look for (or
the object to search for, itself).
The object must consist of field name/value pairs, where
the field names are names of fields specified by the
fields property, in the same order they
are used in that property.
You do not have to specify all of the fields from the
fields property, but you
cannot skip any in the order.
Therefore, if the fields
properity lists three fields, you can specify its first
and second fields in this parameter, but you cannot
specify only the first and third fields.
| |||||||
mode:String — String containing the type of find to perform.
Valid values are:
| |||||||
returnInsertionIndex:Boolean (default = false ) — If the method does not find an item
identified by the values parameter,
and this parameter is true the
findItem()
method returns the insertion point for the values,
that is the point in the sorted order where you
should insert the item.
| |||||||
compareFunction:Function (default = null ) — a comparator function to use to find the item.
If you do not specify this parameter or , or if you
provide a null value,
findItem() function uses the
compare function determined by the ISort
instance's compareFunction property,
passing in the array of fields determined
by the values object and the current
SortFields .
If you provide a non-null value, findItem()
function uses it as the compare function.
The signature of the function passed as
compareFunction must be as follows:
function myCompareFunction(a:Object, b:Object):int .
Note that there is no third argument unlike the
compare function for ISort.compareFunction()
property.
|
int — int The index in the array of the found item.
If the returnInsertionIndex parameter is
false and the item is not found, returns -1.
If the returnInsertionIndex parameter is
true and the item is not found, returns
the index of the point in the sorted array where the
values would be inserted.
|
propertyAffectsSort | () | method |
public function propertyAffectsSort(property:String):Boolean
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 2.5 |
Return whether the specified property is used to control the sort.
The function cannot determine a definitive answer if the sort uses a
custom comparator; it always returns true
in this case.
Parameters
property:String — The name of the field that to test.
|
Boolean — Whether the property value might affect the sort outcome.
If the sort uses the default compareFunction, returns
true if the
property parameter specifies a sort field.
If the sort or any ISortField uses a custom comparator,
there's no way to know, so return true .
|
reverse | () | method |
public function reverse():void
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 2.5 |
Goes through the fields
array and calls
reverse()
on each of the ISortField
objects in
the array. If the field was descending now it is ascending,
and vice versa.
Note: an ICollectionView
does not automatically
update when the objects in the fields
array are modified;
call its refresh()
method to update the view.
sort | () | method |
public function sort(items:Array):void
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 2.5 |
Apply the current sort to the specified array (not a copy).
To prevent the array from being modified, create a copy
use the copy in the items
parameter.
Flex ICollectionView
implementations call the
sort
method automatically and ensure that the sort is
performed on a copy of the underlying data.
Parameters
items:Array — Array of items to sort.
|
ANY_INDEX_MODE | Constant |
public static const ANY_INDEX_MODE:String = "any"
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 2.5 |
When executing a find return the index any matching item.
FIRST_INDEX_MODE | Constant |
public static const FIRST_INDEX_MODE:String = "first"
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 2.5 |
When executing a find return the index for the first matching item.
LAST_INDEX_MODE | Constant |
public static const LAST_INDEX_MODE:String = "last"
Language Version: | ActionScript 3.0 |
Product Version: | Flex 4.5 |
Runtime Versions: | Flash Player 10.1, AIR 2.5 |
When executing a find return the index for the last matching item.
<?xml version="1.0" encoding="utf-8"?> <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600"> <!-- Sample program for spark.collections.Sort and SortField --> <fx:Declarations> <s:Sort id="sortbyLastName_FirstName"> <s:fields> <s:SortField name="last"/> <s:SortField name="first"/> </s:fields> </s:Sort> <mx:ArrayCollection id="collection" sort="{sortbyLastName_FirstName}"> <mx:source> <fx:Object first="Anders" last="Dickerson"/> <fx:Object first="Eileen" last="Maccormick"/> <fx:Object first="Aiden" last="MacCormick"/> <fx:Object first="Steve" last="MacGregor"/> </mx:source> </mx:ArrayCollection> </fx:Declarations> <s:VGroup> <s:VGroup> <s:HGroup> <s:Label text="Input Locale ID Name: "/> <s:TextInput id="inputLocaleIDName"/> <!-- Sets the locale style on the document UI component. The SortField and Sort objects defined in the fx:Declarations section will inherit this style. --> <s:Button click="{setStyle('locale', inputLocaleIDName.text); collection.refresh()}" label="Apply"/> </s:HGroup> <s:Label text="Example: 'en-US', 'fr-FR', 'zh-CN', 'ar-SA'"/> </s:VGroup> <s:DataGrid dataProvider="{collection}" width="100%" creationComplete="{collection.refresh()}"> <s:columns> <s:ArrayList> <s:GridColumn dataField="last"/> <s:GridColumn dataField="first"/> </s:ArrayList> </s:columns> </s:DataGrid> </s:VGroup> </s:Application>
<?xml version="1.0" encoding="utf-8"?> <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600" creationComplete="initApp()"> <!-- Sample program for spark.collections.Sort and SortField --> <fx:Script> <![CDATA[ import mx.collections.ArrayCollection; import spark.collections.*; [Bindable] private var collection:ArrayCollection = new ArrayCollection(); private function localeChange():void { // Sets the locale style on this application. // The SortField objects will inherit this style. setStyle('locale', inputLocaleIDName.text); collection.refresh(); } private function initApp() : void { // Add data to the collection. collection.addItem({first:"Anders", last:"Dickerson"}); collection.addItem({first:"Steve", last:"Maccormick"}); collection.addItem({first:"Aiden", last:"MacCormick"}); collection.addItem({first:"Eileen", last:"MacGregor"}); // Create the Sort instance. var sort:Sort = new Sort(); // Set the sort field; sort on the last name first, first name // second. var sortfieldLastName:SortField = new SortField("last",true); var sortfieldFirstName:SortField = new SortField("first",true); sort.fields = [sortfieldLastName, sortfieldFirstName]; // Add the sort field objects to this application's list of // style clients. This will cause the sort field objects to // inherit the locale style from this Application. addStyleClient(sortfieldLastName); addStyleClient(sortfieldFirstName); // Assign the Sort object to the view. collection.sort = sort; // Apply the sort to the collection. collection.refresh(); } ]]> </fx:Script> <s:VGroup> <s:VGroup> <s:HGroup> <s:Label text="Input Locale ID Name: "/> <s:TextInput id="inputLocaleIDName"/> <s:Button click="localeChange()" label="Apply"/> </s:HGroup> <s:Label text="Example: 'en-US', 'fr-FR', 'zh-CN', 'ar-SA'"/> </s:VGroup> <s:DataGrid dataProvider="{collection}" width="100%" creationComplete="{collection.refresh()}"> <s:columns> <s:ArrayList> <s:GridColumn dataField="last"/> <s:GridColumn dataField="first"/> </s:ArrayList> </s:columns> </s:DataGrid> </s:VGroup> </s:Application>
Thu Dec 6 2018, 01:12 PM -08:00