Java tutorial
/* * 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. */ package events; /* * TreeExpandEventDemo2.java requires no other files. */ import javax.swing.*; import javax.swing.tree.*; import javax.swing.event.*; import java.awt.*; public class TreeExpandEventDemo2 extends JPanel { DemoArea demoArea; JTextArea textArea; final static String newline = "\n"; public TreeExpandEventDemo2() { super(new GridBagLayout()); GridBagLayout gridbag = (GridBagLayout) getLayout(); GridBagConstraints c = new GridBagConstraints(); c.fill = GridBagConstraints.BOTH; c.gridwidth = GridBagConstraints.REMAINDER; c.weightx = 1.0; c.weighty = 1.0; c.insets = new Insets(1, 1, 1, 1); demoArea = new DemoArea(); gridbag.setConstraints(demoArea, c); add(demoArea); c.insets = new Insets(0, 0, 0, 0); textArea = new JTextArea(); textArea.setEditable(false); JScrollPane scrollPane = new JScrollPane(textArea); scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS); scrollPane.setPreferredSize(new Dimension(200, 75)); gridbag.setConstraints(scrollPane, c); add(scrollPane); setPreferredSize(new Dimension(450, 450)); setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20)); } void saySomething(String eventDescription, TreeExpansionEvent e) { textArea.append(eventDescription + "; " + "path = " + e.getPath() + newline); } class DemoArea extends JScrollPane implements TreeExpansionListener, TreeWillExpandListener { Dimension minSize = new Dimension(100, 100); JTree tree; Object[] willExpandOptions = { "Cancel Expansion", "Expand" }; String willExpandText = "A branch node is about to be expanded.\n" + "Click \"Cancel Expansion\" to prevent it."; String willExpandTitle = "Tree Will Expand"; public DemoArea() { TreeNode rootNode = createNodes(); tree = new JTree(rootNode); tree.addTreeExpansionListener(this); tree.addTreeWillExpandListener(this); setViewportView(tree); } private TreeNode createNodes() { DefaultMutableTreeNode root; DefaultMutableTreeNode grandparent; DefaultMutableTreeNode parent; DefaultMutableTreeNode child; root = new DefaultMutableTreeNode("San Francisco"); grandparent = new DefaultMutableTreeNode("Potrero Hill"); root.add(grandparent); // parent = new DefaultMutableTreeNode("Restaurants"); grandparent.add(parent); child = new DefaultMutableTreeNode("Thai Barbeque"); parent.add(child); child = new DefaultMutableTreeNode("Goat Hill Pizza"); parent.add(child); // parent = new DefaultMutableTreeNode("Grocery Stores"); grandparent.add(parent); child = new DefaultMutableTreeNode("Good Life Grocery"); parent.add(child); child = new DefaultMutableTreeNode("Safeway"); parent.add(child); grandparent = new DefaultMutableTreeNode("Noe Valley"); root.add(grandparent); // parent = new DefaultMutableTreeNode("Restaurants"); grandparent.add(parent); child = new DefaultMutableTreeNode("Hamano Sushi"); parent.add(child); child = new DefaultMutableTreeNode("Hahn's Hibachi"); parent.add(child); // parent = new DefaultMutableTreeNode("Grocery Stores"); grandparent.add(parent); child = new DefaultMutableTreeNode("Real Foods"); parent.add(child); child = new DefaultMutableTreeNode("Bell Market"); parent.add(child); return root; } public Dimension getMinimumSize() { return minSize; } public Dimension getPreferredSize() { return minSize; } //Required by TreeWillExpandListener interface. public void treeWillExpand(TreeExpansionEvent e) throws ExpandVetoException { saySomething("Tree-will-expand event detected", e); int n = JOptionPane.showOptionDialog(this, willExpandText, willExpandTitle, JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE, null, willExpandOptions, willExpandOptions[1]); if (n == 0) { //User said cancel expansion. saySomething("Tree expansion cancelled", e); throw new ExpandVetoException(e); } } //Required by TreeWillExpandListener interface. public void treeWillCollapse(TreeExpansionEvent e) { saySomething("Tree-will-collapse event detected", e); } // Required by TreeExpansionListener interface. public void treeExpanded(TreeExpansionEvent e) { saySomething("Tree-expanded event detected", e); } // Required by TreeExpansionListener interface. public void treeCollapsed(TreeExpansionEvent e) { saySomething("Tree-collapsed event detected", e); } } /** * 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("TreeExpandEventDemo2"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. JComponent newContentPane = new TreeExpandEventDemo2(); 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(); } }); } }