防止Tree组件的非叶节点被选中.

<?xml version="1.0" encoding="utf-8"?>

<!-- http://blog.flexexamples.com/2008/01/16/preventing-branches-from-being-selected-in-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.events.ListEvent;

            private function tree_itemClick(evt:ListEvent):void {

                var item:Object = evt.currentTarget.selectedItem

                if (tree.dataDescriptor.isBranch(item)) {

                    tree.selectedItem = null;

                }

            }

        ]]>

    </mx:Script>

    <mx:XML id="dp">

        <root>

            <node label="Parent 1">

                <node label="Child 1" />

                <node label="Child 2">

                    <node label="Grandchild 1" />

                    <node label="Grandchild 2" />

                </node>

                <node label="Child 3" />

                <node label="Child 4" />

            </node>

        </root>

    </mx:XML>

    <mx:Tree id="tree"

            dataProvider="{dp}"

            showRoot="false"

            labelField="@label"

            width="200"

            itemClick="tree_itemClick(event);" />

</mx:Application>