Java 图形用户界面 树形菜单的创建

/**
作者：wwj
日期：2012/4/15
功能：实现创建一个树形菜单
说明：创建树形菜单结构与创建菜单栏类似，是按层次与模型创建的。
通过DefaultMutableTreeNode类创建根节点、子节点和孙节点对象，再通过DefaultTreeModel
类利用根节点创建树模型对象，然后通过treeModel.insertNodeInto方法将节点对象插入树模型中
**/

import java.awt.*;
import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;
public class Tree extends JFrame implements TreeSelectionListener
{
	private JLabel label;

	public Tree()
	{
		super("树形菜单");	setSize(400,400);
		Container container = getContentPane();

		//创建根节点和子节点
		DefaultMutableTreeNode root = new DefaultMutableTreeNode("文本编辑器");
		DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("文件");
		DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("编辑");
		//利用根节点创建TreeModel
		DefaultTreeModel treeModel = new DefaultTreeModel(root);
		//插入子节点node1,node2
		treeModel.insertNodeInto(node1,root,root.getChildCount());
		treeModel.insertNodeInto(node2,root,root.getChildCount());

		//创建节点node1的子节点并插入
		DefaultMutableTreeNode leafnode = new DefaultMutableTreeNode("打开");
		treeModel.insertNodeInto(leafnode,node1,node1.getChildCount());
		leafnode = new DefaultMutableTreeNode("保存");
		treeModel.insertNodeInto(leafnode,node1,node1.getChildCount());
		leafnode = new DefaultMutableTreeNode("另存为");
		treeModel.insertNodeInto(leafnode,node1,node1.getChildCount());
		leafnode = new DefaultMutableTreeNode("关闭");
		treeModel.insertNodeInto(leafnode,node1,node1.getChildCount());

		//创建节点node2的子节点并插入
		leafnode = new DefaultMutableTreeNode("剪切");
		treeModel.insertNodeInto(leafnode,node2,node2.getChildCount());
		leafnode = new DefaultMutableTreeNode("复制");
		treeModel.insertNodeInto(leafnode,node2,node2.getChildCount());
		leafnode = new DefaultMutableTreeNode("粘贴");
		treeModel.insertNodeInto(leafnode,node2,node2.getChildCount());

		//创建树对象
		JTree tree = new JTree(treeModel);
		//设置Tree的选择为一次只能选择一个节点
		tree.getSelectionModel().setSelectionMode(
							TreeSelectionModel.SINGLE_TREE_SELECTION);
		//注册监听器
		tree.addTreeSelectionListener(this);

		tree.setRowHeight(20);

		//创建节点绘制对象
		DefaultTreeCellRenderer cellRenderer =
							(DefaultTreeCellRenderer)tree.getCellRenderer();

		//设置字体
		cellRenderer.setFont(new Font("Serif",Font.PLAIN,14));
		cellRenderer.setBackgroundNonSelectionColor(Color.white);
		cellRenderer.setBackgroundSelectionColor(Color.yellow);
		cellRenderer.setBorderSelectionColor(Color.red);

		//设置选或不选时，文字的变化颜色
		cellRenderer.setTextNonSelectionColor(Color.black);
		cellRenderer.setTextSelectionColor(Color.blue);
		
		//把树对象添加到内容面板
		container.add(new JScrollPane(tree));

		//创建标签
		label = new JLabel("你当前选择的节点为：",JLabel.CENTER);
		label.setFont(new Font("Serif",Font.PLAIN,14));
		container.add(label,BorderLayout.SOUTH);

		setVisible(true);	//设置可见
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);	//设置窗口关闭动作
	}

	//处理TreeSelectionEvent事件
	public void valueChanged(TreeSelectionEvent event)
	{
		JTree tree = (JTree)event.getSource();
		//获取目前选取的节点
		DefaultMutableTreeNode selectionNode =
			(DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
		String nodeName = selectionNode.toString();
		label.setText("你当前选取的节点为： "+nodeName);
	}

	public static void main(String args[])
	{
		Tree d = new Tree();
	}

}