flex实现树状网络布局，可以灵活的添加，删除节点，收缩展开子节点，功能可扩展，可以-flex tree network topology to achieve the flexibility to add, delete node, expand the child nodes shrink, the function can be extended

演示在树形结构中，怎样添加新节点并进行编辑。观察节点的展开以及收缩，以及滚动面板怎样让添加的节点保持在视图中。-Demonstration in the tree structure, how to add a new node and edit it. From one node to the start and shrink, and how to add scrolling panel to keep the nodes in the view.

本例子实现了 Flex tree 节点的展开与收缩 , 可以展开所有节点，展开第一层节点，展开名为child5的节点，收缩所有节点-expand the tree of flex , shrink the tree of flex