Java树形菜单的创建

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。

效果图：

代码：

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();
 } 

} 

本文按层次与模型创建的树形菜单，与创建菜单栏类似，不知道小伙伴们有没有掌握呐？