Java examples for Swing:Event
Handle List Data Event
/*/*from w w w . j a v a 2 s . c o m*/ * ListDataEventDemo.java requires the Java Look and Feel Graphics * Repository (jlfgr-1_0.jar). You can download this file from * http://java.sun.com/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.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; import java.net.URL; public class ListDataEventDemo 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 ListDataEventDemo() { 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 = ListDataEventDemo.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 ListDataEventDemo(); 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(); } }); } } /* * 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. */