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);
    }
}