Handle Key Event - Java Swing

Description

Handle Key Event
Demo Code

/*//  w w  w. j  a  v a  2  s .c o  m
 * 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());
    }
}

/*
 * 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.
 */
Handle Key Event - Java Swing

Description

Demo Code

Related Tutorials
