Java by API/javax.swing.event/ListSelectionListener
implements ListSelectionListener
<source lang="java">
/*
* Copyright (c) 1995 - 2008 Sun Microsystems, Inc. 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 Sun Microsystems nor 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. */
/*
* ListDataEventDemo.java requires the Java Look and Feel Graphics * Repository (jlfgr-1_0.jar). You can download this file from * http://java.sun.ru/developer/techDocs/hi/repository/ * Put it in the class path using one of the following commands * (assuming jlfgr-1_0.jar is in a subdirectory named jars): * * java -cp .;jars/jlfgr-1_0.jar ListDataEventDemo [Microsoft Windows] * java -cp .:jars/jlfgr-1_0.jar ListDataEventDemo [UNIX] */
import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.GridLayout; import java.awt.Insets; import java.awt.Toolkit; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.DefaultListModel; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.JList; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JSplitPane; import javax.swing.JTextArea; import javax.swing.JTextField; import javax.swing.ListSelectionModel; import javax.swing.event.ListDataEvent; import javax.swing.event.ListDataListener; import javax.swing.event.ListSelectionEvent; import javax.swing.event.ListSelectionListener; public class Main extends JPanel implements ListSelectionListener {
private JList list;
private DefaultListModel listModel;
private static final String addString = "Add";
private static final String deleteString = "Delete";
private static final String upString = "Move up";
private static final String downString = "Move down";
private JButton addButton;
private JButton deleteButton;
private JButton upButton;
private JButton downButton;
private JTextField nameField;
private JTextArea log;
static private String newline = "\n";
public Main() {
super(new BorderLayout());
// Create and populate the list model.
listModel = new DefaultListModel();
listModel.addElement("Whistler, Canada");
listModel.addElement("Jackson Hole, Wyoming");
listModel.addElement("Squaw Valley, California");
listModel.addElement("Telluride, Colorado");
listModel.addElement("Taos, New Mexico");
listModel.addElement("Snowbird, Utah");
listModel.addElement("Chamonix, France");
listModel.addElement("Banff, Canada");
listModel.addElement("Arapahoe Basin, Colorado");
listModel.addElement("Kirkwood, California");
listModel.addElement("Sun Valley, Idaho");
listModel.addListDataListener(new MyListDataListener());
// Create the list and put it in a scroll pane.
list = new JList(listModel);
list.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
list.setSelectedIndex(0);
list.addListSelectionListener(this);
JScrollPane listScrollPane = new JScrollPane(list);
// Create the list-modifying buttons.
addButton = new JButton(addString);
addButton.setActionCommand(addString);
addButton.addActionListener(new AddButtonListener());
deleteButton = new JButton(deleteString);
deleteButton.setActionCommand(deleteString);
deleteButton.addActionListener(new DeleteButtonListener());
ImageIcon icon = createImageIcon("Up16");
if (icon != null) {
upButton = new JButton(icon);
upButton.setMargin(new Insets(0, 0, 0, 0));
} else {
upButton = new JButton("Move up");
}
upButton.setToolTipText("Move the currently selected list item higher.");
upButton.setActionCommand(upString);
upButton.addActionListener(new UpDownListener());
icon = createImageIcon("Down16");
if (icon != null) {
downButton = new JButton(icon);
downButton.setMargin(new Insets(0, 0, 0, 0));
} else {
downButton = new JButton("Move down");
}
downButton.setToolTipText("Move the currently selected list item lower.");
downButton.setActionCommand(downString);
downButton.addActionListener(new UpDownListener());
JPanel upDownPanel = new JPanel(new GridLayout(2, 1));
upDownPanel.add(upButton);
upDownPanel.add(downButton);
// Create the text field for entering new names.
nameField = new JTextField(15);
nameField.addActionListener(new AddButtonListener());
String name = listModel.getElementAt(list.getSelectedIndex()).toString();
nameField.setText(name);
// Create a control panel, using the default FlowLayout.
JPanel buttonPane = new JPanel();
buttonPane.add(nameField);
buttonPane.add(addButton);
buttonPane.add(deleteButton);
buttonPane.add(upDownPanel);
// Create the log for reporting list data events.
log = new JTextArea(10, 20);
JScrollPane logScrollPane = new JScrollPane(log);
// Create a split pane for the log and the list.
JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
listScrollPane, logScrollPane);
splitPane.setResizeWeight(0.5);
// Put everything together.
add(buttonPane, BorderLayout.PAGE_START);
add(splitPane, BorderLayout.CENTER);
}
class MyListDataListener implements ListDataListener {
public void contentsChanged(ListDataEvent e) {
log.append("contentsChanged: " + e.getIndex0() + ", " + e.getIndex1()
+ newline);
log.setCaretPosition(log.getDocument().getLength());
}
public void intervalAdded(ListDataEvent e) {
log.append("intervalAdded: " + e.getIndex0() + ", " + e.getIndex1()
+ newline);
log.setCaretPosition(log.getDocument().getLength());
}
public void intervalRemoved(ListDataEvent e) {
log.append("intervalRemoved: " + e.getIndex0() + ", " + e.getIndex1()
+ newline);
log.setCaretPosition(log.getDocument().getLength());
}
}
class DeleteButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
/*
* This method can be called only if there"s a valid selection, so go
* ahead and remove whatever"s selected.
*/
ListSelectionModel lsm = list.getSelectionModel();
int firstSelected = lsm.getMinSelectionIndex();
int lastSelected = lsm.getMaxSelectionIndex();
listModel.removeRange(firstSelected, lastSelected);
int size = listModel.size();
if (size == 0) {
// List is empty: disable delete, up, and down buttons.
deleteButton.setEnabled(false);
upButton.setEnabled(false);
downButton.setEnabled(false);
} else {
// Adjust the selection.
if (firstSelected == listModel.getSize()) {
// Removed item in last position.
firstSelected--;
}
list.setSelectedIndex(firstSelected);
}
}
}
/** A listener shared by the text field and add button. */
class AddButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
if (nameField.getText().equals("")) {
// User didn"t type in a name...
Toolkit.getDefaultToolkit().beep();
return;
}
int index = list.getSelectedIndex();
int size = listModel.getSize();
// If no selection or if item in last position is selected,
// add the new one to end of list, and select new one.
if (index == -1 || (index + 1 == size)) {
listModel.addElement(nameField.getText());
list.setSelectedIndex(size);
// Otherwise insert the new one after the current selection,
// and select new one.
} else {
listModel.insertElementAt(nameField.getText(), index + 1);
list.setSelectedIndex(index + 1);
}
}
}
// Listen for clicks on the up and down arrow buttons.
class UpDownListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
// This method can be called only when
// there"s a valid selection,
// so go ahead and move the list item.
int moveMe = list.getSelectedIndex();
if (e.getActionCommand().equals(upString)) {
// UP ARROW BUTTON
if (moveMe != 0) {
// not already at top
swap(moveMe, moveMe - 1);
list.setSelectedIndex(moveMe - 1);
list.ensureIndexIsVisible(moveMe - 1);
}
} else {
// DOWN ARROW BUTTON
if (moveMe != listModel.getSize() - 1) {
// not already at bottom
swap(moveMe, moveMe + 1);
list.setSelectedIndex(moveMe + 1);
list.ensureIndexIsVisible(moveMe + 1);
}
}
}
}
// Swap two elements in the list.
private void swap(int a, int b) {
Object aObject = listModel.getElementAt(a);
Object bObject = listModel.getElementAt(b);
listModel.set(a, bObject);
listModel.set(b, aObject);
}
// Listener method for list selection changes.
public void valueChanged(ListSelectionEvent e) {
if (e.getValueIsAdjusting() == false) {
if (list.getSelectedIndex() == -1) {
// No selection: disable delete, up, and down buttons.
deleteButton.setEnabled(false);
upButton.setEnabled(false);
downButton.setEnabled(false);
nameField.setText("");
} else if (list.getSelectedIndices().length > 1) {
// Multiple selection: disable up and down buttons.
deleteButton.setEnabled(true);
upButton.setEnabled(false);
downButton.setEnabled(false);
} else {
// Single selection: permit all operations.
deleteButton.setEnabled(true);
upButton.setEnabled(true);
downButton.setEnabled(true);
nameField.setText(list.getSelectedValue().toString());
}
}
}
/** Returns an ImageIcon, or null if the path was invalid. */
protected static ImageIcon createImageIcon(String imageName) {
String imgLocation = "toolbarButtonGraphics/navigation/" + imageName
+ ".gif";
java.net.URL imageURL = Main.class.getResource(imgLocation);
if (imageURL == null) {
System.err.println("Resource not found: " + imgLocation);
return null;
} else {
return new ImageIcon(imageURL);
}
}
/**
* 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("ListDataEventDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create and set up the content pane.
JComponent newContentPane = new Main();
newContentPane.setOpaque(true); // content panes must be opaque
frame.setContentPane(newContentPane);
// Don"t let the content pane get too small.
// (Works if the Java look and feel provides
// the window decorations.)
newContentPane.setMinimumSize(new Dimension(newContentPane
.getPreferredSize().width, 100));
// 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();
}
});
}
}
</source>
