Tree data is from XMLListCollection
<?xml version="1.0"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"> <mx:Tree labelField="@label" width="200"> <mx:XMLListCollection> <mx:XMLList> <state label="A"> <city label="A1" /> <city label="A2" /> </state> <state label="B"> <city label="B1" /> </state> </mx:XMLList> </mx:XMLListCollection> </mx:Tree> </mx:Application>