Java/Event/Swing Action
Содержание
Demonstrate a listener being reused
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002. All rights
* reserved. Software written by Ian F. Darwin and others. $Id: LICENSE,v 1.8
* 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer. 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee cup"
* logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.awt.Button;
import java.awt.Frame;
import java.awt.Menu;
import java.awt.MenuBar;
import java.awt.MenuItem;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class ListenerReuse extends Frame {
public ListenerReuse() {
Button b = new Button("Save");
add(b);
MenuBar mb = new MenuBar();
setMenuBar(mb);
Menu fm = new Menu("File");
mb.add(fm);
MenuItem mi = new MenuItem("Save");
fm.add(mi);
// Construct the ActionListener, and keep a reference to it.
ActionListener saver = new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Saving your file...");
// In real life we would call the doSave() method
// in the main class, something like this:
// mainProg.doSave();
}
};
// Register the actionListener with the Button
b.addActionListener(saver);
// And now register the same actionListener with the MenuItem
mi.addActionListener(saver);
pack();
}
/** Main just calls the above */
public static void main(String[] a) {
ListenerReuse lr = new ListenerReuse();
lr.setVisible(true);
}
}
Derive a class from a component and implement an action listener inside the class.
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
class MyButton extends JButton implements ActionListener {
public MyButton(String text) {
super.setText(text);
addActionListener(this);
}
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
public class UsingInterface {
public static void main(String[] args) {
MyButton close = new MyButton("Close");
JFrame f = new JFrame();
f.add(close);
f.setSize(300, 200);
f.setLocationRelativeTo(null);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
}
How to have multiple listeners
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
/**
* Demo I wrote in response to a student request for how to have multiple
* listeners (Bobs) that are already on-screen added as listeners to a
* newly-created pushbutton (Fred).
*/
public class MultiListeners {
public static void main(String[] args) {
Bob b1 = new Bob();
b1.setVisible(true);
Bob b2 = new Bob();
b2.setVisible(true);
ActionListener[] bobs = { b1, b2 };
Fred f1 = new Fred(bobs);
f1.setVisible(true);
}
}
class Fred extends JFrame {
JButton okbutton = new JButton("OK");
public Fred(ActionListener[] bobs) {
getContentPane().add(okbutton);
for (int i = 0; i < bobs.length; i++) {
okbutton.addActionListener(bobs[i]);
}
}
}
class Bob extends JFrame implements ActionListener {
protected JLabel statusLabel = new JLabel(" ");
public Bob() {
getContentPane().add(statusLabel);
}
public void actionPerformed(ActionEvent e) {
statusLabel.setText("OK");
}
}
Keymap and KeyStroke Demo
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.KeyStroke;
import javax.swing.text.Keymap;
public class DefaultSample {
public static void main(String args[]) {
JFrame frame = new JFrame("Default Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container content = frame.getContentPane();
JTextField textField = new JTextField();
content.add(textField, BorderLayout.NORTH);
ActionListener actionListener = new ActionListener() {
public void actionPerformed(ActionEvent actionEvent) {
System.out
.println(actionEvent.getActionCommand() + " selected");
}
};
JPanel panel = new JPanel();
JButton defaultButton = new JButton("Default Button");
defaultButton.addActionListener(actionListener);
panel.add(defaultButton);
JButton otherButton = new JButton("Other Button");
otherButton.addActionListener(actionListener);
panel.add(otherButton);
content.add(panel, BorderLayout.SOUTH);
Keymap keymap = textField.getKeymap();
KeyStroke keystroke = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0,
false);
keymap.removeKeyStrokeBinding(keystroke);
frame.getRootPane().setDefaultButton(defaultButton);
frame.setSize(250, 150);
frame.setVisible(true);
}
}
Use Action class
import java.awt.Color;
import java.awt.ruponent;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
public class ColorAction extends AbstractAction {
public ColorAction(String name, Icon icon, Color c, Component comp) {
putValue(Action.NAME, name);
putValue(Action.SMALL_ICON, icon);
putValue("Color", c);
target = comp;
}
public void actionPerformed(ActionEvent evt) {
Color c = (Color) getValue("Color");
target.setBackground(c);
target.repaint();
}
private Component target;
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setTitle("SeparateGUITest");
frame.setSize(300, 200);
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
JPanel panel = new JPanel();
Action blueAction = new ColorAction("Blue", new ImageIcon(
"blue-ball.gif"), Color.blue, panel);
Action yellowAction = new ColorAction("Yellow", new ImageIcon(
"yellow-ball.gif"), Color.yellow, panel);
Action redAction = new ColorAction("Red",
new ImageIcon("red-ball.gif"), Color.red, panel);
panel.add(new JButton(yellowAction));
panel.add(new JButton(blueAction));
panel.add(new JButton(redAction));
panel.registerKeyboardAction(yellowAction, KeyStroke.getKeyStroke(
KeyEvent.VK_Y, 0), JComponent.WHEN_IN_FOCUSED_WINDOW);
panel.registerKeyboardAction(blueAction, KeyStroke.getKeyStroke(
KeyEvent.VK_B, 0), JComponent.WHEN_IN_FOCUSED_WINDOW);
panel.registerKeyboardAction(redAction, KeyStroke.getKeyStroke(
KeyEvent.VK_R, 0), JComponent.WHEN_IN_FOCUSED_WINDOW);
Container contentPane = frame.getContentPane();
contentPane.add(panel);
JMenu m = new JMenu("Color");
m.add(yellowAction);
m.add(blueAction);
m.add(redAction);
JMenuBar mbar = new JMenuBar();
mbar.add(m);
frame.setJMenuBar(mbar);
frame.show();
}
}
You can change event behavior dynamically
// : c14:DynamicEvents.java
// You can change event behavior dynamically.
// Also shows multiple actions for an event.
// <applet code=DynamicEvents
// width=250 height=400></applet>
// From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002
// www.BruceEckel.ru. See copyright notice in CopyRight.txt.
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class DynamicEvents extends JApplet {
private java.util.List list = new ArrayList();
private int i = 0;
private JButton b1 = new JButton("Button1"), b2 = new JButton("Button2");
private JTextArea txt = new JTextArea();
class B implements ActionListener {
public void actionPerformed(ActionEvent e) {
txt.append("A button was pressed\n");
}
}
class CountListener implements ActionListener {
private int index;
public CountListener(int i) {
index = i;
}
public void actionPerformed(ActionEvent e) {
txt.append("Counted Listener " + index + "\n");
}
}
class B1 implements ActionListener {
public void actionPerformed(ActionEvent e) {
txt.append("Button 1 pressed\n");
ActionListener a = new CountListener(i++);
list.add(a);
b2.addActionListener(a);
}
}
class B2 implements ActionListener {
public void actionPerformed(ActionEvent e) {
txt.append("Button2 pressed\n");
int end = list.size() - 1;
if (end >= 0) {
b2.removeActionListener((ActionListener) list.get(end));
list.remove(end);
}
}
}
public void init() {
Container cp = getContentPane();
b1.addActionListener(new B());
b1.addActionListener(new B1());
b2.addActionListener(new B());
b2.addActionListener(new B2());
JPanel p = new JPanel();
p.add(b1);
p.add(b2);
cp.add(BorderLayout.NORTH, p);
cp.add(new JScrollPane(txt));
}
public static void main(String[] args) {
run(new DynamicEvents(), 250, 400);
}
public static void run(JApplet applet, int width, int height) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(applet);
frame.setSize(width, height);
applet.init();
applet.start();
frame.setVisible(true);
}
} ///:~
