Packagemx.collections
Classpublic class SortField
InheritanceSortField Inheritance flash.events.EventDispatcher
Implements ISortField
Subclasses SortField

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1


Starting with Flex 4.5, Apache recommends that you use the spark.collections.SortField class as an alternative to this class.

Provides the sorting information required to establish a sort on a field or property in a collection view. The SortField class is meant to be used with the Sort class. Typically the sort is defined for collections of complex items, that is items in which the sort is performed on properties of those objects. As in the following example: 
                  
     var col:ICollectionView = new ArrayCollection();
     col.addItem({first:"Anders", last:"Dickerson"});
     var sort:Sort = new Sort();
     sort.fields = [new SortField("first", true)];
     col.sort = sort;
There are situations in which the collection contains simple items, like String, Date, Boolean, etc. In this case, sorting should be applied to the simple type directly. When constructing a sort for this situation only a single sort field is required and should not have a name specified. For example: 
                  
     var col:ICollectionView = new ArrayCollection();
     col.addItem("California");
     col.addItem("Arizona");
     var sort:Sort = new Sort();
     sort.fields = [new SortField(null, true)];
     col.sort = sort;

By default the comparison provided by the SortField class does not provide correct language specific sorting for strings. For this type of sorting please see the spark.collections.Sort and spark.collections.SortField classes.

Note: to prevent problems like FLEX-34853 it is recommended to use SortField instances as immutable objects (by not changing their state).

MXML SyntaxexpandedHide MXML Syntax

The <mx:SortField> tag has the following attributes:

  <mx:SortField
  Properties
  caseInsensitive="false"
  compareFunction="Internal compare function"
  descending="false"
  name="null"
  numeric="null"
  />

See also

mx.collections.ICollectionView
mx.collections.Sort
spark.collections.Sort
spark.collections.SortField

Public Properties
 PropertyDefined By
  arraySortOnOptions : int
[read-only] This helper property is used internally by the findItem() and sort() methods.
SortField
  caseInsensitive : Boolean
[read-only] Specifies whether the sort for this field should be case insensitive.
SortField
  compareFunction : Function
The function that compares two items during a sort of items for the associated collection.
SortField
  descending : Boolean
Specifies whether this field should be sorted in descending order.
SortField
  name : String
The name of the field to be sorted.
SortField
  numeric : Object
Specifies that if the field being sorted contains numeric (number/int/uint) values, or string representations of numeric values, the comparator use a numeric comparison.
SortField
  sortCompareType : String
Specifies what compare type will be used for the sortField.
SortField
  usingCustomCompareFunction : Boolean
[read-only] True if this ISortField uses a custom comparator function.
SortField
Public Methods
 MethodDefined By
  
SortField(name:String = null, caseInsensitive:Boolean = false, descending:Boolean = false, numeric:Object = null, sortCompareType:String = null, customCompareFunction:Function = null)
Constructor.
SortField
  
initializeDefaultCompareFunction(obj:Object):void
A helper function called by the Sort class to set the default comparison function to perform a comparison based on one of three things: whether or not a custom compare function has been set, the data type for the specified field or the the value of the numeric property.
SortField
  
objectHasSortField(object:Object):Boolean
SortField
  
reverse():void
Reverse the criteria for this sort field.
SortField
  
updateSortCompareType():Boolean
This changes the internal compare function used by the SortField based on the value of sortCompareType.
SortField
Protected Methods
 MethodDefined By
  
getSortFieldValue(obj:Object):*
SortField
  
stringCompare(a:Object, b:Object):int
Pull the strings from the objects and call the implementation.
SortField
  
xmlCompare(a:Object, b:Object):int
Pull the values out fo the XML object, then compare using the string or numeric comparator depending on the numeric flag.
SortField
Property Detail
arraySortOnOptionsproperty
arraySortOnOptions:int  [read-only]

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

This helper property is used internally by the findItem() and sort() methods. Other uses of this property are not supported. Returns -1 if this ISortField shouldn't be used by the Sort class to sort the field (there is no compareFunction or no name). Otherwise, returns a bitmask of sort options.


Implementation
    public function get arraySortOnOptions():int
caseInsensitiveproperty 
caseInsensitive:Boolean  [read-only]

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

Specifies whether the sort for this field should be case insensitive.

The default value is false.

This property can be used as the source for data binding.


Implementation
    public function get caseInsensitive():Boolean
compareFunctionproperty 
compareFunction:Function

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

The function that compares two items during a sort of items for the associated collection. If you specify a compareFunction property in an ISort object, Flex ignores any compareFunction properties of the ISort's SortField objects.

The compare function must have the following signature:

function myCompare(a:Object, b:Object):int

This function must return the following values:

The default value is an internal compare function that can perform a string, numeric, or date comparison in ascending or descending order, with case-sensitive or case-insensitive string comparisons. 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.

Note if you need language-specific sorting then consider using the spark.collections.SortField class.


Implementation
    public function get compareFunction():Function
    public function set compareFunction(value:Function):void

See also

spark.collections.SortField
descendingproperty 
descending:Boolean

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

Specifies whether this field should be sorted in descending order.

The default value is false (ascending).

This property can be used as the source for data binding.


Implementation
    public function get descending():Boolean
    public function set descending(value:Boolean):void
nameproperty 
name:String

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

The name of the field to be sorted.

The default value is null.

This property can be used as the source for data binding.


Implementation
    public function get name():String
    public function set name(value:String):void
numericproperty 
numeric:Object

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

Specifies that if the field being sorted contains numeric (number/int/uint) values, or string representations of numeric values, the comparator use a numeric comparison.

This property is used by SortField class in case custom compare function is not provided.

If this property is true, the built-in numeric compare function is used. Each of data items is cast to a Number() function before the comparison.

If this property is false, the built-in string compare function is used. Each of data items is cast to a String() function before the comparison.

If this property is null, the first data item is introspected to see if it is a number or string and the sort proceeds based on that introspection.

The default value is null.

This property can be used as the source for data binding.


Implementation
    public function get numeric():Object
    public function set numeric(value:Object):void
sortCompareTypeproperty 
sortCompareType:String

Language Version : ActionScript 3.0
Product Version : Flex 4.11
Runtime Versions : Flash Player 11.8, AIR 3.8

Specifies what compare type will be used for the sortField. This overrides the default behavior.

This property can be used as the source for data binding.


Implementation
    public function get sortCompareType():String
    public function set sortCompareType(value:String):void
usingCustomCompareFunctionproperty 
usingCustomCompareFunction:Boolean  [read-only]

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

True if this ISortField uses a custom comparator function.


Implementation
    public function get usingCustomCompareFunction():Boolean
Constructor Detail
SortField()Constructor
public function SortField(name:String = null, caseInsensitive:Boolean = false, descending:Boolean = false, numeric:Object = null, sortCompareType:String = null, customCompareFunction:Function = null)

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

Constructor.

Parameters
name:String (default = null) — The name of the property that this field uses for comparison. If the object is a simple type, pass null.
 
caseInsensitive:Boolean (default = false) — When sorting strings, tells the comparator whether to ignore the case of the values.
 
descending:Boolean (default = false) — Tells the comparator whether to arrange items in descending order.
 
numeric:Object (default = null) — Tells the comparator whether to compare sort items as numbers, instead of alphabetically.
 
sortCompareType:String (default = null) — Gives an indication to SortField which of the default compare functions to use.
 
customCompareFunction:Function (default = null) — Use a custom function to compare the objects based on this SortField.
Method Detail
getSortFieldValue()method
protected function getSortFieldValue(obj:Object):*

Parameters

obj:Object

Returns
*
initializeDefaultCompareFunction()method 
public function initializeDefaultCompareFunction(obj:Object):void

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

A helper function called by the Sort class to set the default comparison function to perform a comparison based on one of three things: whether or not a custom compare function has been set, the data type for the specified field or the the value of the numeric property. If the the numeric property is true, then a numeric comparison will be performed when sorting.

Parameters

obj:Object — The object that contains the data. If the field name has been set with the name property, then the name will be used to access the data value from this object. Otherwise the object itself will be used as the data value.

objectHasSortField()method 
public function objectHasSortField(object:Object):Boolean

Parameters

object:Object

Returns
Boolean
reverse()method 
public function reverse():void

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

Reverse the criteria for this sort field. If the field was sorted in descending order, for example, sort it in ascending order.

NOTE: An ICollectionView does not automatically update when the ISortFields are modified; call its refresh() method to update the view.

Note: a future release of Apache Flex SDK will change the signature of this function to return a reversed clone of this SortField instance. See FLEX-34853 for more details.

stringCompare()method 
protected function stringCompare(a:Object, b:Object):int

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

Pull the strings from the objects and call the implementation.

Parameters

a:Object
 
b:Object

Returns
int
updateSortCompareType()method 
public function updateSortCompareType():Boolean

Language Version : ActionScript 3.0
Product Version : Flex 4.11
Runtime Versions : Flash Player 11.8, AIR 3.8

This changes the internal compare function used by the SortField based on the value of sortCompareType.

Returns
Boolean — true for successfully matched or false for failure to match the sortCompareType.
xmlCompare()method 
protected function xmlCompare(a:Object, b:Object):int

Language Version : ActionScript 3.0
Product Version : Flex 3
Runtime Versions : Flash Player 9, AIR 1.1

Pull the values out fo the XML object, then compare using the string or numeric comparator depending on the numeric flag.

Parameters

a:Object
 
b:Object

Returns
int



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Wed Nov 15 2017, 09:50 AM +01:00