Java tutorial
/* From http://java.sun.com/docs/books/tutorial/index.html */ /* * Copyright (c) 2006 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: * * -Redistribution of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * -Redistribution 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, Inc. or the names of contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * This software is provided "AS IS," without a warranty of any kind. ALL * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. * * You acknowledge that this software is not designed, licensed or intended * for use in the design, construction, operation or maintenance of any * nuclear facility. */ /* * KeyEventDemo.java is a 1.4 example that requires no other files. */ import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import javax.swing.JButton; import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.JTextField; public class KeyEventDemo extends JPanel implements KeyListener, ActionListener { JTextArea displayArea; JTextField typingArea; static final String newline = "\n"; public KeyEventDemo() { super(new BorderLayout()); JButton button = new JButton("Clear"); button.addActionListener(this); typingArea = new JTextField(20); typingArea.addKeyListener(this); //Uncomment this if you wish to turn off focus //traversal. The focus subsystem consumes //focus traversal keys, such as Tab and Shift Tab. //If you uncomment the following line of code, this //disables focus traversal and the Tab events will //become available to the key event listener. //typingArea.setFocusTraversalKeysEnabled(false); displayArea = new JTextArea(); displayArea.setEditable(false); JScrollPane scrollPane = new JScrollPane(displayArea); scrollPane.setPreferredSize(new Dimension(375, 125)); add(typingArea, BorderLayout.PAGE_START); add(scrollPane, BorderLayout.CENTER); add(button, BorderLayout.PAGE_END); } /** Handle the key typed event from the text field. */ public void keyTyped(KeyEvent e) { displayInfo(e, "KEY TYPED: "); } /** Handle the key pressed event from the text field. */ public void keyPressed(KeyEvent e) { displayInfo(e, "KEY PRESSED: "); } /** Handle the key released event from the text field. */ public void keyReleased(KeyEvent e) { displayInfo(e, "KEY RELEASED: "); } /** Handle the button click. */ public void actionPerformed(ActionEvent e) { //Clear the text components. displayArea.setText(""); typingArea.setText(""); //Return the focus to the typing area. typingArea.requestFocusInWindow(); } /* * We have to jump through some hoops to avoid trying to print non-printing * characters such as Shift. (Not only do they not print, but if you put * them in a String, the characters afterward won't show up in the text * area.) */ protected void displayInfo(KeyEvent e, String s) { String keyString, modString, tmpString, actionString, locationString; //You should only rely on the key char if the event //is a key typed event. int id = e.getID(); if (id == KeyEvent.KEY_TYPED) { char c = e.getKeyChar(); keyString = "key character = '" + c + "'"; } else { int keyCode = e.getKeyCode(); keyString = "key code = " + keyCode + " (" + KeyEvent.getKeyText(keyCode) + ")"; } int modifiers = e.getModifiersEx(); modString = "modifiers = " + modifiers; tmpString = KeyEvent.getModifiersExText(modifiers); if (tmpString.length() > 0) { modString += " (" + tmpString + ")"; } else { modString += " (no modifiers)"; } actionString = "action key? "; if (e.isActionKey()) { actionString += "YES"; } else { actionString += "NO"; } locationString = "key location: "; int location = e.getKeyLocation(); if (location == KeyEvent.KEY_LOCATION_STANDARD) { locationString += "standard"; } else if (location == KeyEvent.KEY_LOCATION_LEFT) { locationString += "left"; } else if (location == KeyEvent.KEY_LOCATION_RIGHT) { locationString += "right"; } else if (location == KeyEvent.KEY_LOCATION_NUMPAD) { locationString += "numpad"; } else { // (location == KeyEvent.KEY_LOCATION_UNKNOWN) locationString += "unknown"; } displayArea.append(s + newline + " " + keyString + newline + " " + modString + newline + " " + actionString + newline + " " + locationString + newline); displayArea.setCaretPosition(displayArea.getDocument().getLength()); } /** * Create the GUI and show it. For thread safety, this method should be * invoked from the event-dispatching thread. */ private static void createAndShowGUI() { //Make sure we have nice window decorations. JFrame.setDefaultLookAndFeelDecorated(true); //Create and set up the window. JFrame frame = new JFrame("KeyEventDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. JComponent newContentPane = new KeyEventDemo(); 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(); } }); } }