The following example shows how you can use the openItems property to determine which branches are currently open in a Flex Tree control.
Full code after the jump.
<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/12/01/determining-which-tree-branches-are-open-using-the-openitems-property/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="vertical"
verticalAlign="middle"
backgroundColor="white">
<mx:Script>
<![CDATA[
import mx.events.TreeEvent;
import mx.utils.ObjectUtil;
private function tree_openItems_change(evt:TreeEvent):void {
/* Set the array and let binding do the real work. */
openItemArr = tree.openItems as Array;
}
]]>
</mx:Script>
<mx:Array id="openItemArr" />
<mx:XML id="xmlDP">
<node>
<node label="1.a" />
<node label="1.b" />
<node label="1.c">
<node label="1.c.i" />
<node label="1.c.ii" />
<node label="1.c.iii" />
<node label="1.c.iv" />
<node label="1.c.v" />
</node>
<node label="1.d" />
<node label="1.e">
<node label="1.e.i" />
<node label="1.e.ii" />
<node label="1.e.iii">
<node label="1.e.iii.A" />
</node>
<node label="1.e.iv" />
</node>
<node label="1.f" />
</node>
</mx:XML>
<mx:ApplicationControlBar dock="true">
<mx:Label text="Tree openItems length: {openItemArr.length}" />
</mx:ApplicationControlBar>
<mx:HDividedBox width="100%">
<mx:Tree id="tree"
dataProvider="{xmlDP}"
labelField="@label"
showRoot="false"
width="50%"
rowCount="8"
itemOpen="tree_openItems_change(event);"
itemClose="tree_openItems_change(event);" />
<mx:List id="list"
dataProvider="{openItemArr}"
labelField="@label"
width="50%"
height="100%" />
<mx:TextArea id="textArea"
editable="false"
text="{ObjectUtil.toString(openItemArr)}"
width="50%"
height="100%" />
</mx:HDividedBox>
</mx:Application>
View source is enabled in the following example.
