JAVA GUI学习 - JTree树结构组件学习 ***

 public class JTreeKnow extends JFrame
 {
     public JTreeKnow()
     {
         this.setBounds(300, 100, 400, 500);
         this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         //创建树的第一种方式
         JTree jTree = new JTree();
         this.add(jTree);

         //创建树的第二种方式：推荐
         //创建根节点
         DefaultMutableTreeNode defaultMutableTreeNode = new DefaultMutableTreeNode("根节点");
         //创建树模型
         DefaultTreeModel defaultTreeModel = new DefaultTreeModel(defaultMutableTreeNode);
         //创建树
         JTree jTree2 = new JTree(defaultTreeModel);
         //创建滚动面板
         JScrollPane jScrollPane = new JScrollPane(jTree2);
         this.add(jScrollPane);
         //添加子节点
         for(int i = 1; i < 3; i++)
         {
             DefaultMutableTreeNode defaultMutableTreeNode2 = new DefaultMutableTreeNode("第一阶子节点"+i);
             for(int j = 1; j < 4; j++)
             {
                 DefaultMutableTreeNode defaultMutableTreeNode3 = new DefaultMutableTreeNode("第二阶子节点"+i+j);
                 defaultMutableTreeNode2.add(defaultMutableTreeNode3);
             }
             defaultMutableTreeNode.add(defaultMutableTreeNode2);
         }

         //获取根节点
         DefaultMutableTreeNode defaultMutableTreeNode2 = (DefaultMutableTreeNode) defaultTreeModel.getRoot();
         //根据父节点索引+子节点索引找到节点
         DefaultMutableTreeNode defaultMutableTreeNode3 = (DefaultMutableTreeNode) defaultTreeModel.getChild(defaultMutableTreeNode2, 0);
         System.out.println(defaultMutableTreeNode3);
         //获取某一节点到顶级节点（根节点）之间所有的节点

         //获取某节点所对应的阶层
         int level = defaultMutableTreeNode3.getLevel();

         //刷新重新绘制节点数（重要）
         defaultTreeModel.reload();
         //获取所有节点：迭代器
         Enumeration<DefaultMutableTreeNode> nodes = defaultMutableTreeNode.children();
         //判断某节点是否是根节点、页节点isLeaf()
         ((DefaultMutableTreeNode)defaultMutableTreeNode.getChildAt(0)).isRoot();

         /*******************************************监听器****************************************/
         //
         /***************JTree的监听器**************/
         //绑定选项监听器
         //某节点被选中了
         jTree2.addTreeSelectionListener(new TreeSelectionListener()
         {
             @Override
             public void valueChanged(TreeSelectionEvent e)
             {
                 // TODO Auto-generated method stub
 //                System.out.println("节点被选择");
                 //获取选中的treePath,treePath即根节点至所选节点的集合
 //                System.out.println(tree.getSelectionPath());
 //                //获取节点集合的数量
 //                System.out.println(tree.getSelectionPath().getPathCount());
 //                //获取选中的节点对象
 //                System.out.println((DefaultMutableTreeNode)tree.getSelectionPath().getLastPathComponent());

                 System.out.println(e.getPath().getLastPathComponent());
             }
         });
         //为降低程序的错误率，监听器addTreeWillExpandListener和监听器addTreeExpansionListener通常会同时搭配使用，
         //以确保程序菜单正常、正确打开
         //绑定数结展开折叠的监听器
         //节点被展开了
         jTree2.addTreeExpansionListener(new TreeExpansionListener()
         {
             /**
              * 展开事件
              */
             @Override
             public void treeExpanded(TreeExpansionEvent event)
             {
                 // TODO Auto-generated method stub
                 System.out.println(event.getPath().getLastPathComponent()+" 被展开");
             }
             /**
              * 折叠
              */
             @Override
             public void treeCollapsed(TreeExpansionEvent event)
             {
                 // TODO Auto-generated method stub
                 System.out.println(event.getPath().getLastPathComponent()+" 被折叠");
             }
         });

         //绑定树结构将要执行展开和折叠的监听器
         //节点将被展开：通常使用本方法对节点进行动态的显示控制
         jTree2.addTreeWillExpandListener(new TreeWillExpandListener()
         {
             /**
              * 将被展开的事件
              */
             @Override
             public void treeWillExpand(TreeExpansionEvent event)
                     throws ExpandVetoException
             {
                 // TODO Auto-generated method stub
                 System.out.println(event.getPath().getLastPathComponent()+" 将被展开");

             }
             /**
              * 将被折叠的事件
              */
             @Override
             public void treeWillCollapse(TreeExpansionEvent event)
                     throws ExpandVetoException
             {
                 // TODO Auto-generated method stub
                 System.out.println(event.getPath().getLastPathComponent()+" 将被折叠");
             }
         });
     }
     public static void main(String[] args)
     {
         JTreeKnow jTreeKnow = new JTreeKnow();
         jTreeKnow.setVisible(true);
     }
 }