Setting the selected indices on a Spark List control in Flex 4

By Peter deHaan On June 16, 2009 · 6 Comments

The following example shows how you can set the selected indices on a Spark List control in Flex 4 by setting the selectedIndices property to a Vector object.

For more information on MXML Vector support in Flex 4, see the MXML Vector Support spec on the Adobe Open Source Flex SDK site.

Full code after the jump.

The following example(s) require Flash Player 10 and the Adobe Flex 4 SDK. To download the Adobe Flash Builder 4 trial, see http://www.adobe.com/products/flex/. To download the latest nightly build of the Flex 4 SDK, see http://opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4.
For more information on getting started with Flex 4 and Flash Builder 4, see the official Adobe Flex Team blog.

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/06/16/setting-the-selected-indices-on-a-spark-list-control-in-flex-4/ -->
<s:Application name="Spark_List_selectedIndices_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/halo">
 
    <fx:Script>
        <![CDATA[
            private function button1_click(evt:MouseEvent):void {
                /** longhand */
                /*
                var victor:Vector.<int> = new Vector.<int>();
                victor.push(1, 3);
                list.selectedIndices = victor;
                */
 
                /** shorthand */
                list.selectedIndices = new <int>[1, 3];
            }
        ]]>
    </fx:Script>
 
    <mx:ApplicationControlBar width="100%" cornerRadius="0">
        <s:Button label="clear selectedIndices"
                click="list.selectedIndices = null;" />
        <s:Button label="set selectedIndices (MXML)"
                click="list.selectedIndices = new &lt;int&gt;[4,6];" />
        <s:Button label="set selectedIndices (ActionScript)"
                click="button1_click(event);" />
    </mx:ApplicationControlBar>
 
    <s:List id="list"
            labelField="label"
            requireSelection="false"
            allowMultipleSelection="true"
            horizontalCenter="0"
            verticalCenter="0">
        <s:dataProvider>
            <s:ArrayList>
                <fx:Object label="(0) One" />
                <fx:Object label="(1) Two*" />
                <fx:Object label="(2) Three" />
                <fx:Object label="(3) Four*" />
                <fx:Object label="(4) Five **" />
                <fx:Object label="(5) Six" />
                <fx:Object label="(6) Seven **" />
                <fx:Object label="(7) Eight" />
                <fx:Object label="(8) Nine" />
            </s:ArrayList>
        </s:dataProvider>
        <s:selectedIndices>
            <fx:Vector type="int">
                <fx:int>1</fx:int>
                <fx:int>3</fx:int>
            </fx:Vector>
        </s:selectedIndices>
    </s:List>
 
</s:Application>

Or, you can set the selectedIndices property inline using data binding, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/06/16/setting-the-selected-indices-on-a-spark-list-control-in-flex-4/ -->
<s:Application name="Spark_List_selectedIndices_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/halo">
 
    <s:List id="list"
            labelField="label"
            requireSelection="false"
            allowMultipleSelection="true"
            selectedIndices="{new &lt;int&gt;[1,3]}"
            horizontalCenter="0" verticalCenter="0">
        <s:dataProvider>
            <s:ArrayList>
                <fx:Object label="(0) One" />
                <fx:Object label="(1) Two*" />
                <fx:Object label="(2) Three" />
                <fx:Object label="(3) Four*" />
                <fx:Object label="(4) Five **" />
                <fx:Object label="(5) Six" />
                <fx:Object label="(6) Seven **" />
                <fx:Object label="(7) Eight" />
                <fx:Object label="(8) Nine" />
            </s:ArrayList>
        </s:dataProvider>
    </s:List>
 
</s:Application>

This entry is based on a beta version of the Flex 4 SDK and therefore is very likely to change as development of the Flex SDK continues. The API can (and will) change causing examples to possibly not compile in newer versions of the Flex 4 SDK.

Tagged with: Gumbo • selectedIndices

About The Author

Peter deHaan

Peter deHaan currently works for Adobe on the Flex SDK QA team. While not working on Flex, Flash, and ColdFusion applications, Peter enjoys making up bios and writing in 3rd person. Peter's rarely updated blog can be found at blogs.adobe.com/pdehaan/, actionscriptexamples.com, airexamples.com, and coldfusionexamples.com.

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6 Responses to Setting the selected indices on a Spark List control in Flex 4

Peter deHaan says:

June 17, 2009 at 4:35 pm

Note: This example requires Flex SDK 4.0.0.7916, or newer.

Reply
Anonymous says:

June 19, 2009 at 12:30 am

Description Resource Path Location Type
1067: Implicit coercion of a value of type __AS3__.vec:Vector. to an unrelated type Array. ListIndcs.mxml GumboExample/src line 15 Flex Problem

Reply
Peter deHaan says:

June 19, 2009 at 6:55 am

Anonymous,

Are you using Flex SDK 4.0.0.7916, or newer? http://opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4

Peter

Reply
JabbyPanda says:

June 23, 2009 at 1:53 am

I’ve downloaded the latest daily build as of today (4.0.0.8031, Sat Jun 20, 2009), still the error is here:

Description Resource Path Location Type
1067: Implicit coercion of a value of type __AS3__.vec:Vector. to an unrelated type __AS3__.vec:Vector.. Hello3.mxml Hello3/src line 19 Flex Problem

Reply
Peter deHaan says:

June 23, 2009 at 7:43 am

JabbyPanda,

Right you are! It looks like the Vector.<Number> was changed to Vector.<int>.

I updated the example above and verified it with build 8031.

Peter

Reply
Penguineer says:

April 4, 2011 at 1:17 pm

I can’t seem to get my commands to set selectedIndices. Here is some of my code and what happens:

trace (“last Indices” + _lastSelectedIndices_vector);
//vector is created and loaded elsewhere. Trace shows proper selected indices.

trace (“current Indices” + selectedIndices);
//trace shows current indices.

if (_lastSelectedIndices_vector){
selectedIndices = _lastSelectedIndices_vector;
}

trace (“selected Indices” + selectedIndices);
//trace shows original selected Indices

I have tried several formats for the setting command but no joy.

Suggestions?

Reply