java树 JTree实例（可动态添加节点）

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import javax.swing.tree.*;

 

class Branch {

    DefaultMutableTreeNode r;

 

    // DefaultMutableTreeNode是树的数据结构中的通用节点,节点也可以有多个子节点。

    public Branch(String[] data) {

        r = new DefaultMutableTreeNode(data[0]);

        for (int i = 1; i < data.length; i++)

            r.add(new DefaultMutableTreeNode(data[i]));

        // 给节点r添加多个子节点

    }

 

    public DefaultMutableTreeNode node() {// 返回节点

        return r;

    }

}

 

public class Trees extends JPanel {

    String[][] data = { { "Colors", "Red", "Blue", "Green" },

            { "Flavors", "Tart", "Sweet", "Bland" },

            { "Length", "Short", "Medium", "Long" },

            { "Volume", "High", "Medium", "Low" },

            { "Temperature", "High", "Medium", "Low" },

            { "Intensity", "High", "Medium", "Low" } };

    static int i = 0; // I用于统计按钮点击的次数

    DefaultMutableTreeNode root, child, chosen;

    JTree tree;

    DefaultTreeModel model;

 

    public Trees() {

        setLayout(new BorderLayout());

        root = new DefaultMutableTreeNode("root");

        // 根节点进行初始化

        tree = new JTree(root);

        // 树进行初始化，其数据来源是root对象

        add(new JScrollPane(tree));

        // 把滚动面板添加到Trees中

        model = (DefaultTreeModel) tree.getModel();

        // 获得数据对象DefaultTreeModel

        JButton test = new JButton("Press me");

        // 按钮test进行初始化

        test.addActionListener(new ActionListener() {

            // 按钮test注册监听器

            public void actionPerformed(ActionEvent e) {

                if (i < data.length) {

                    // 按钮test点击的次数小于data的长度

                    child = new Branch(data[i++]).node();

                    // 生成子节点

                    chosen = (DefaultMutableTreeNode)

                    // 选择child的父节点

                    tree.getLastSelectedPathComponent();

                    if (chosen == null)

                        chosen = root;

                    model.insertNodeInto(child, chosen, 0);

                    // 把child添加到chosen

                }

            }

        });

        test.setBackground(Color.blue);

        // 按钮test设置背景色为蓝色

        test.setForeground(Color.white);

        // 按钮test设置前景色为白色

        JPanel p = new JPanel();

        // 面板p初始化

        p.add(test);

        // 把按钮添加到面板p中

        add(p, BorderLayout.SOUTH);

        // 把面板p添加到Trees中

    }

 

    public static void main(String args[]) {

        JFrame jf = new JFrame("JTree demo");

 

        jf.getContentPane().add(new Trees(), BorderLayout.CENTER);

        // 把Trees对象添加到JFrame对象的中央

        jf.setSize(200, 500);

        jf.setVisible(true);

    }

}