一个Oracle Java KeyListener/KeyEvent例子程序

・8 分钟阅读

下面的Java源代码来自这个Oracle URL 。我目前正在使用Java/Scala Swing keycode/keystroke事件做很多工作,包括KeyListener和KeyEvent类型的事情。

/**
 * 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;
/*
* KeyEventDemo
*/
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.*;
import javax.swing.*;
public class KeyEventDemo extends JFrame
 implements KeyListener,
 ActionListener
{
 JTextArea displayArea;
 JTextField typingArea;
 static final String newline = System.getProperty(\"line.separator\");
 public static void main(String[] args) {
 /* Use an appropriate Look and Feel */
 try {
 //UIManager.setLookAndFeel(\"com.sun.java.swing.plaf.windows.WindowsLookAndFeel\");
 //UIManager.setLookAndFeel(\"com.sun.java.swing.plaf.gtk.GTKLookAndFeel\");
 UIManager.setLookAndFeel(\"javax.swing.plaf.metal.MetalLookAndFeel\");
 } catch (UnsupportedLookAndFeelException ex) {
 ex.printStackTrace();
 } catch (IllegalAccessException ex) {
 ex.printStackTrace();
 } catch (InstantiationException ex) {
 ex.printStackTrace();
 } catch (ClassNotFoundException ex) {
 ex.printStackTrace();
 }
 /* Turn off metal\'s use of bold fonts */
 UIManager.put(\"swing.boldMetal\", Boolean.FALSE);
 //Schedule a job for event dispatch thread:
 //creating and showing this application\'s GUI.
 javax.swing.SwingUtilities.invokeLater(new Runnable() {
 public void run() {
 createAndShowGUI();
 }
 });
 }
 /**
 * 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.
 KeyEventDemo frame = new KeyEventDemo(\"KeyEventDemo\");
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 //Set up the content pane.
 frame.addComponentsToPane();
 //Display the window.
 frame.pack();
 frame.setVisible(true);
 }
 private void addComponentsToPane() {
 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));
 getContentPane().add(typingArea, BorderLayout.PAGE_START);
 getContentPane().add(scrollPane, BorderLayout.CENTER);
 getContentPane().add(button, BorderLayout.PAGE_END);
 }
 public KeyEventDemo(String name) {
 super(name);
 }
 /** 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.)
 */
 private void displayInfo(KeyEvent e, String keyStatus){
 //You should only rely on the key char if the event
 //is a key typed event.
 int id = e.getID();
 String keyString;
 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 modifiersEx = e.getModifiersEx();
 String modString =\"extended modifiers =\" + modifiersEx;
 String tmpString = KeyEvent.getModifiersExText(modifiersEx);
 if (tmpString.length() > 0) {
 modString +=\" (\" + tmpString +\")\";
 } else {
 modString +=\" (no extended modifiers)\";
 }
 String actionString =\"action key?\";
 if (e.isActionKey()) {
 actionString +=\"YES\";
 } else {
 actionString +=\"NO\";
 }
 String 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(keyStatus + newline
 +\"\" + keyString + newline
 +\"\" + modString + newline
 +\"\" + actionString + newline
 +\"\" + locationString + newline);
 displayArea.setCaretPosition(displayArea.getDocument().getLength());
 }
}

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