Flex中如何利用isBranch()事件，检测Tree的节点是支节点还是叶子节点

main.mxml

1. <?xml version="1.0" encoding="utf-8"?>
2. <mx:Applicationxmlns:mx="http://www.adobe.com/2006/mxml"
3. layout="vertical"
4. verticalAlign="middle"
5. backgroundColor="white">
7. <mx:Script>
8. <![CDATA[
9. import mx.events.ListEvent;
11. private function tree_itemClick(evt:ListEvent):void {
12. var itemIsBranch:Boolean = tree.dataDescriptor.isBranch(tree.selectedItem);
13. lbl.text = itemIsBranch.toString();
14. }
16. private function tree_labelFunc(item:XML):String {
17. var returnStr:String = item.@label;
18. var itemIsBranch:Boolean = tree.dataDescriptor.isBranch(item);
19. if (itemIsBranch) {
20. returnStr += " (BRANCH)";
21. }
22. return returnStr;
23. }
24. ]]>
25. </mx:Script>
27. <mx:XMLid="xmlDP">
28. <node>
29. <nodelabel="1.a" />
30. <nodelabel="1.b" />
31. <nodelabel="1.c">
32. <nodelabel="1.c.i" />
33. <nodelabel="1.c.ii" />
34. <nodelabel="1.c.iii" />
35. <nodelabel="1.c.iv" />
36. <nodelabel="1.c.v" />
37. </node>
38. <nodelabel="1.d" />
39. <nodelabel="1.e">
40. <nodelabel="1.e.i" />
41. <nodelabel="1.e.ii" />
42. <nodelabel="1.e.iii">
43. <nodelabel="1.e.iii.A" />
44. </node>
45. <nodelabel="1.e.iv" />
46. </node>
47. <nodelabel="1.f" />
48. </node>
49. </mx:XML>
51. <mx:ApplicationControlBardock="true">
52. <mx:FormstyleName="plain">
53. <mx:FormItemlabel="isBranch():">
54. <mx:Labelid="lbl" fontWeight="bold" />
55. </mx:FormItem>
56. </mx:Form>
57. </mx:ApplicationControlBar>
59. <mx:Treeid="tree"
60. dataProvider="{xmlDP}"
61. labelFunction="tree_labelFunc"
62. showRoot="false"
63. width="50%"
64. rowCount="6"
65. itemClick="tree_itemClick(event);"/>
67. </mx:Application>