Use Custom object used as tree node - Java Swing

Java examples for Swing:JTree

Description

Use Custom object used as tree node

Demo Code

/**//from  ww w  .j  av  a2 s.  c  o m
 * A 1.4 application that requires the following additional files:
 *   TreeDemoHelp.html
 *    arnold.html
 *    bloch.html
 *    chan.html
 *    jls.html
 *    swingtutorial.html
 *    tutorial.html
 *    tutorialcont.html
 *    vm.html
 */

import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;

import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreeSelectionModel;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.ImageIcon;

import java.net.URL;
import java.io.IOException;
import java.awt.Dimension;
import java.awt.GridLayout;

public class TreeIconDemo extends JPanel implements TreeSelectionListener {
    private JEditorPane htmlPane;
    private JTree tree;
    private URL helpURL;
    private static boolean DEBUG = false;

    public TreeIconDemo() {
        super(new GridLayout(1, 0));

        //Create the nodes.
        DefaultMutableTreeNode top = new DefaultMutableTreeNode(
                "The Java Series");
        createNodes(top);

        //Create a tree that allows one selection at a time.
        tree = new JTree(top);
        tree.getSelectionModel().setSelectionMode(
                TreeSelectionModel.SINGLE_TREE_SELECTION);

        //Set the icon for leaf nodes.
        ImageIcon leafIcon = createImageIcon("images/middle.gif");
        if (leafIcon != null) {
            DefaultTreeCellRenderer renderer = new DefaultTreeCellRenderer();
            renderer.setLeafIcon(leafIcon);
            tree.setCellRenderer(renderer);
        } else {
            System.err.println("Leaf icon missing; using default.");
        }

        //Listen for when the selection changes.
        tree.addTreeSelectionListener(this);

        //Create the scroll pane and add the tree to it. 
        JScrollPane treeView = new JScrollPane(tree);

        //Create the HTML viewing pane.
        htmlPane = new JEditorPane();
        htmlPane.setEditable(false);
        initHelp();
        JScrollPane htmlView = new JScrollPane(htmlPane);

        //Add the scroll panes to a split pane.
        JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
        splitPane.setTopComponent(treeView);
        splitPane.setBottomComponent(htmlView);

        Dimension minimumSize = new Dimension(100, 50);
        htmlView.setMinimumSize(minimumSize);
        treeView.setMinimumSize(minimumSize);
        splitPane.setDividerLocation(100); //XXX: ignored in some releases
                                           //of Swing. bug 4101306
        //workaround for bug 4101306:
        //treeView.setPreferredSize(new Dimension(100, 100)); 

        splitPane.setPreferredSize(new Dimension(500, 300));

        //Add the split pane to this panel.
        add(splitPane);
    }

    /** Required by TreeSelectionListener interface. */
    public void valueChanged(TreeSelectionEvent e) {
        DefaultMutableTreeNode node = (DefaultMutableTreeNode) tree
                .getLastSelectedPathComponent();

        if (node == null)
            return;

        Object nodeInfo = node.getUserObject();
        if (node.isLeaf()) {
            BookInfo book = (BookInfo) nodeInfo;
            displayURL(book.bookURL);
            if (DEBUG) {
                System.out.print(book.bookURL + ":  \n    ");
            }
        } else {
            displayURL(helpURL);
        }
        if (DEBUG) {
            System.out.println(nodeInfo.toString());
        }
    }

    private class BookInfo {
        public String bookName;
        public URL bookURL;

        public BookInfo(String book, String filename) {
            bookName = book;
            bookURL = TreeIconDemo.class.getResource(filename);
            if (bookURL == null) {
                System.err.println("Couldn't find file: " + filename);
            }
        }

        public String toString() {
            return bookName;
        }
    }

    private void initHelp() {
        String s = "TreeDemoHelp.html";
        helpURL = TreeIconDemo.class.getResource(s);
        if (helpURL == null) {
            System.err.println("Couldn't open help file: " + s);
        } else if (DEBUG) {
            System.out.println("Help URL is " + helpURL);
        }

        displayURL(helpURL);
    }

    private void displayURL(URL url) {
        try {
            if (url != null) {
                htmlPane.setPage(url);
            } else { //null url
                htmlPane.setText("File Not Found");
                if (DEBUG) {
                    System.out.println("Attempted to display a null URL.");
                }
            }
        } catch (IOException e) {
            System.err.println("Attempted to read a bad URL: " + url);
        }
    }

    private void createNodes(DefaultMutableTreeNode top) {
        DefaultMutableTreeNode category = null;
        DefaultMutableTreeNode book = null;

        category = new DefaultMutableTreeNode("Books for Java Programmers");
        top.add(category);

        //original Tutorial
        book = new DefaultMutableTreeNode(new BookInfo(
                "The Java Tutorial: A Short Course on the Basics",
                "tutorial.html"));
        category.add(book);

        //Tutorial Continued
        book = new DefaultMutableTreeNode(new BookInfo(
                "The Java Tutorial Continued: The Rest of the JDK",
                "tutorialcont.html"));
        category.add(book);

        //JFC Swing Tutorial
        book = new DefaultMutableTreeNode(new BookInfo(
                "The JFC Swing Tutorial: A Guide to Constructing GUIs",
                "swingtutorial.html"));
        category.add(book);

        //Bloch
        book = new DefaultMutableTreeNode(new BookInfo(
                "Effective Java Programming Language Guide", "bloch.html"));
        category.add(book);

        //Arnold/Gosling
        book = new DefaultMutableTreeNode(new BookInfo(
                "The Java Programming Language", "arnold.html"));
        category.add(book);

        //Chan
        book = new DefaultMutableTreeNode(new BookInfo(
                "The Java Developers Almanac", "chan.html"));
        category.add(book);

        category = new DefaultMutableTreeNode("Books for Java Implementers");
        top.add(category);

        //VM
        book = new DefaultMutableTreeNode(new BookInfo(
                "The Java Virtual Machine Specification", "vm.html"));
        category.add(book);

        //Language Spec
        book = new DefaultMutableTreeNode(new BookInfo(
                "The Java Language Specification", "jls.html"));
        category.add(book);
    }

    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) {
        java.net.URL imgURL = TreeIconDemo.class.getResource(path);
        if (imgURL != null) {
            return new ImageIcon(imgURL);
        } else {
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("TreeIconDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        TreeIconDemo newContentPane = new TreeIconDemo();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

/*
 * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

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