java examples
Home Java Examples Resources Java Interview Questions
Brainpower SEO

How to get the selected nodes of a JTree?

The following example show how to use the JTree.getSelectionPaths() method to get the selected node of a JTree component. This method returns an array of TreePath objects. In the case to get the last node in the path we can call the TreePath.getLastPathComponent().

In the code below when you pressed the button the listener gets the selection paths and print out the last path component of the selected nodes.

package com.javacoderanch.example.swing;

import javax.swing.*;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreePath;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class JTreeGetSelectedNode extends JFrame {
    public JTreeGetSelectedNode() throws HeadlessException {
        initializeUI();
    }

    private void initializeUI() {
        setSize(200, 400);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        DefaultMutableTreeNode root = new DefaultMutableTreeNode("Countries");
        DefaultMutableTreeNode asia = new DefaultMutableTreeNode("Asia");
        String[] countries = new String[] {"India", "Singapore", "Indonesia", "Vietnam"};
        for (String country : countries) {
            DefaultMutableTreeNode node = new DefaultMutableTreeNode(country);
            asia.add(node);
        }

        DefaultMutableTreeNode northAmerica = new DefaultMutableTreeNode("North America");
        countries = new String[] {"United States", "Canada"};
        for (String country : countries) {
            DefaultMutableTreeNode node = new DefaultMutableTreeNode(country);
            northAmerica.add(node);
        }

        DefaultMutableTreeNode southAmerica = new DefaultMutableTreeNode("South America");
        countries = new String[] {"Brazil", "Argetina", "Uruguay"};
        for (String country : countries) {
            DefaultMutableTreeNode node = new DefaultMutableTreeNode(country);
            southAmerica.add(node);
        }

        DefaultMutableTreeNode europe = new DefaultMutableTreeNode("Europe");
        countries = new String[] {"United Kingdom", "Germany", "Spain", "France", "Italy"};
        for (String country : countries) {
            DefaultMutableTreeNode node = new DefaultMutableTreeNode(country);
            europe.add(node);
        }

        root.add(asia);
        root.add(northAmerica);
        root.add(southAmerica);
        root.add(europe);

        final JTree tree = new JTree(root);
        JScrollPane pane = new JScrollPane(tree);
        pane.setPreferredSize(new Dimension(200, 400));


        JButton button = new JButton("Get Selected");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                TreePath[] paths = tree.getSelectionPaths();

                for (TreePath path : paths) {
                    System.out.println("You've selected: " + path.getLastPathComponent());
                }
            }
        });

        getContentPane().setLayout(new BorderLayout());
        getContentPane().add(pane, BorderLayout.CENTER);
        getContentPane().add(button, BorderLayout.SOUTH);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new JTreeGetSelectedNode().setVisible(true);
            }
        });
    }
}