The following example shows how you can change the open duration and open easing function on a Tree control in Flex by setting the openDuration and openEasingFunction styles.
Full code after the jump.
<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/11/27/changing-the-open-duration-and-easing-function-on-a-flex-tree-control/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="vertical"
verticalAlign="middle"
backgroundColor="white">
<mx:Script>
<![CDATA[
import mx.effects.easing.*;
]]>
</mx:Script>
<mx:XMLListCollection id="xmlListColl">
<mx:source>
<mx:XMLList>
<node label="One">
<node label="One.1" />
<node label="One.2" />
<node label="One.3" />
</node>
<node label="Two">
<node label="Two.1" />
<node label="Two.2" />
<node label="Two.3" />
</node>
</mx:XMLList>
</mx:source>
</mx:XMLListCollection>
<mx:Tree id="tree"
dataProvider="{xmlListColl}"
labelField="@label"
selectionColor="haloBlue"
textSelectedColor="white"
openDuration="3000"
openEasingFunction="Bounce.easeOut"
fontSize="24"
fontWeight="bold"
rowHeight="40"
rowCount="4"
width="300" />
</mx:Application>
View source is enabled in the following example.

{ 3 comments… read them below or add one }
Is it just me or does this not work very well with FileSystemTree?
thebouv,
I’ve never tried a FileSystemTree control, but if it looks like a bug can you please file a bug (and include a simple test case, if possible) at http://bugs.adobe.com/flex/ if it isn’t already in the bugbase. (Please file against the “Flex SDK” project and “AIR: File System Tree” Component.)
Thanks,
Peter
Hope I made sense in my bug report:
http://bugs.adobe.com/jira/browse/SDK-17846
So, while I wait to find out about that, any hint on dragging a folder onto an AIR app and listing the directories/files/subdirectories in a Tree instead of a FileSystemTree? :-)