How to sort an ArrayCollection in Flex

I want to sort an Arraycollection by fieldName as ascending. Here's my code and I want to know whether it's right. Do you have any suggestions?

public static function arrayCollectionSort(ar:ArrayCollection, fieldName:String, isNumeric:Boolean):void 
    {var dataSortField:SortField = new SortField();
        dataSortField.name = fieldName;
        dataSortField.numeric = isNumeric;
        var numericDataSort:Sort = new Sort();
        numericDataSort.fields = [dataSortField];
        arrCol.sort = numericDataSort;
        arrCol.refresh();}

回答1:

The code you have is correct, except for a type. arrCol should be ar. The code looks almost exactly like the code at the blog Flex Examples, which is also correct.

Just change is change arrCol to ar like below:

public static function arrayCollectionSort(ar:ArrayCollection, fieldName:String, isNumeric:Boolean):void 
{
    var dataSortField:SortField = new SortField();
    dataSortField.name = fieldName;
    dataSortField.numeric = isNumeric;
    var numericDataSort:Sort = new Sort();
    numericDataSort.fields = [dataSortField];
    ar.sort = numericDataSort;
    ar.refresh();
}

Not sure with numeric but otherwise everything else is correct.

回答2:

Here is full example how to use sort in Array collection

http://blog.flexexamples.com/2007/08/05/sorting-an-arraycollection-using-the-sortfield-and-sort-classes/

回答3:

Your code is fine, even so here are a couple of examples where a numeric and an alphabetical sort is applied on button clicks.

The alphabetical sort is a good example of sorting on 2 attributes. In this case, the primary sort is done on the 'firstname', the secondary sort is done on the 'lastname'.

The numerical sort is quite flexible, if you provide a boolean value of true for the numeric parameter of the sort field, the sort will cast the attribute to a number and sort by number. If you provide a boolean value of false, the built-in string compare function is used. Each of data items is cast to a String() function before the comparison. With the default value of null, the first data item is introspected to see if it is a number or string and the sort proceeds based on that introspection.

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" minWidth="955" minHeight="600">

    <mx:Button label="Sort by first then last name" click="sortItemsByName()"/>
    <mx:Button label="Sort by number" click="sortItemsByNumber()"/>

    <mx:DataGrid dataProvider="{items}"
                 width="300"
                 height="300">
        <mx:columns>
            <mx:DataGridColumn dataField="number"/>
            <mx:DataGridColumn dataField="firstname"/>
            <mx:DataGridColumn dataField="lastname"/>
        </mx:columns>
    </mx:DataGrid>

    <mx:ArrayCollection id="items">
        <mx:Object number="3" firstname="John" lastname="Brown"/>
        <mx:Object number="1" firstname="Kate" lastname="Brown"/>
        <mx:Object number="4" firstname="Jeremy" lastname="Ryan"/>
        <mx:Object number="5" firstname="Joe" lastname="Wilson"/>
        <mx:Object number="2" firstname="Greg" lastname="Walling"/>
    </mx:ArrayCollection>

    <mx:Script>
        <![CDATA[           
            import mx.collections.ArrayCollection;
            import mx.collections.Sort;
            import mx.collections.SortField;

            /**
             * Sort the arraycollection by the firstname and then the last name
             * */
            private function sortItemsByName():void{
                var srt:Sort = new Sort();
                srt.fields = [new SortField("firstname"), new SortField("lastname")];
                items.sort = srt;
                items.refresh();
            }

            /**
             * Sort the arraycollection numerically
             * */
            private function sortItemsByNumber():void{
                var srt:Sort = new Sort();
                srt.fields = [new SortField("number", true, false, true)];
                items.sort = srt;
                items.refresh();
            }

        ]]>
    </mx:Script>
</mx:Application>

Also here is the language reference for the sortField...

http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/mx/collections/SortField.html

...and the Adobe livedocs reference for data providers and collections...

http://livedocs.adobe.com/flex/3/html/help.html?content=about_dataproviders_2.html

...and here is a good livedocs reference for sorting and filtering...

http://livedocs.adobe.com/flex/3/html/help.html?content=about_dataproviders_4.html