eventtestpane.java

JAVA 实例手册源码 Examples From Java Examples in a Nutshell, 2nd Edition

/*
 * Copyright (c) 2000 David Flanagan.  All rights reserved.
 * This code is from the book Java Examples in a Nutshell, 2nd Edition.
 * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
 * You may study, use, and modify it for any non-commercial purpose.
 * You may distribute it non-commercially as long as you retain this notice.
 * For a commercial use license, or to purchase the book (recommended),
 * visit http://www.davidflanagan.com/javaexamples2.
 */
package com.davidflanagan.examples.gui;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;

/** A program that displays all the event that occur in its window */
public class EventTestPane extends JPanel {
    /** The constructor: register the event types we are interested in */
    public EventTestPane() {
	// We're interested in all types of events
	this.enableEvents(AWTEvent.MOUSE_EVENT_MASK |
			  AWTEvent.MOUSE_MOTION_EVENT_MASK |
			  AWTEvent.KEY_EVENT_MASK |
			  AWTEvent.FOCUS_EVENT_MASK |
			  AWTEvent.COMPONENT_EVENT_MASK |
			  AWTEvent.WINDOW_EVENT_MASK);
	this.setPreferredSize(new Dimension(500, 400));
    }
    
    /**
     * Display mouse events that don't involve mouse motion.  The mousemods()
     * method prints modifiers, and is defined below.  The other methods
     * return additional information about the mouse event.  showLine()
     * displays a line of text in the window.  It is defined at the end of
     * this class, along with the paintComponent() method.
     **/
    public void processMouseEvent(MouseEvent e) {
	String type = null;
	switch(e.getID()) {
	case MouseEvent.MOUSE_PRESSED:   type = "MOUSE_PRESSED"; break;
	case MouseEvent.MOUSE_RELEASED:  type = "MOUSE_RELEASED"; break;
	case MouseEvent.MOUSE_CLICKED:   type = "MOUSE_CLICKED"; break;
	case MouseEvent.MOUSE_ENTERED:   type = "MOUSE_ENTERED"; break;
	case MouseEvent.MOUSE_EXITED:    type = "MOUSE_EXITED"; break;
	}
	showLine(mousemods(e) + type +
		 ": [" + e.getX() + "," + e.getY() + "] " +
		 "num clicks = " + e.getClickCount() +
		 (e.isPopupTrigger()?"; is popup trigger":""));

	// When the mouse enters the component, request keyboard focus so
	// we can receive and respond to keyboard events
	if (e.getID() == MouseEvent.MOUSE_ENTERED)
	    requestFocus();
    }
    
    /**
     * Display mouse moved and dragged mouse event.  Note that MouseEvent is
     * the only event type that has two methods, two EventListener interfaces
     * and two adapter classes to handle two distinct categories of events.
     * Also, as seen in init(), mouse motion events must be requested
     * separately from other mouse event types.
     **/
    public void processMouseMotionEvent(MouseEvent e) {
	String type = null;
	switch(e.getID()) {
	case MouseEvent.MOUSE_MOVED:   type = "MOUSE_MOVED"; break;
	case MouseEvent.MOUSE_DRAGGED: type = "MOUSE_DRAGGED"; break;
	}
	showLine(mousemods(e) + type +
		 ": [" + e.getX() + "," + e.getY() + "] " +
		 "num clicks = " + e.getClickCount() +
		 (e.isPopupTrigger()?"; is popup trigger":""));
    }
    
    /**
     * Return a string representation of the modifiers for a MouseEvent.
     * Note that the methods called here are inherited from InputEvent.
     **/
    protected String mousemods(MouseEvent e) {
	int mods = e.getModifiers();
	String s = "";
	if (e.isShiftDown()) s += "Shift ";
	if (e.isControlDown()) s += "Ctrl ";
	if ((mods & InputEvent.BUTTON1_MASK) != 0) s += "Button 1 ";
	if ((mods & InputEvent.BUTTON2_MASK) != 0) s += "Button 2 ";
	if ((mods & InputEvent.BUTTON3_MASK) != 0) s += "Button 3 ";
	return s;
    }

    /**
     * Display keyboard events.
     *
     * Note that there are three distinct types of key events, and that key
     * events are reported by key code and/or Unicode character.  KEY_PRESSED
     * and KEY_RELEASED events are generated for all key strokes.  KEY_TYPED
     * events are only generated when a key stroke produces a Unicode
     * character; these events do not report a key code.  If isActionKey()
     * returns true, then the key event reports only a key code, because the
     * key that was pressed or released (such as a function key) has no
     * corresponding Unicode character.  Key codes can be interpreted by using
     * the many VK_ constants defined by the KeyEvent class, or they can be
     * converted to strings using the static getKeyText() method as we do
     * here.
     **/
    public void processKeyEvent(KeyEvent e) {
	String eventtype, modifiers, code, character;
	switch(e.getID()) {
	case KeyEvent.KEY_PRESSED:  eventtype = "KEY_PRESSED"; break;
	case KeyEvent.KEY_RELEASED: eventtype = "KEY_RELEASED"; break;
	case KeyEvent.KEY_TYPED:    eventtype = "KEY_TYPED"; break;
	default: eventtype = "UNKNOWN";
	}
	
	// Convert the list of modifier keys to a string
	modifiers = KeyEvent.getKeyModifiersText(e.getModifiers());
	
	// Get string and numeric versions of the key code, if any.
	if (e.getID() == KeyEvent.KEY_TYPED) code = "";
	else code = "Code=" + KeyEvent.getKeyText(e.getKeyCode()) +
		 " (" + e.getKeyCode() + ")";
	
	// Get string and numeric versions of the Unicode character, if any.
	if (e.isActionKey()) character = "";
	else character = "Character=" + e.getKeyChar() +
		 " (Unicode=" + ((int)e.getKeyChar()) + ")";
	
	// Display it all.
	showLine(eventtype + ": " + modifiers + " " + code + " " + character);
    }
    
    /**
     * Display keyboard focus events.  Focus can be permanently gained or
     * lost, or temporarily transferred to or from a component.
     **/
    public void processFocusEvent(FocusEvent e) {
	if (e.getID() == FocusEvent.FOCUS_GAINED)
	    showLine("FOCUS_GAINED" + (e.isTemporary()?" (temporary)":""));
	else
	    showLine("FOCUS_LOST" + (e.isTemporary()?" (temporary)":""));
    }
    
    /** Display Component events.  */
    public void processComponentEvent(ComponentEvent e) {
	switch(e.getID()) {
	case ComponentEvent.COMPONENT_MOVED:
	    showLine("COMPONENT_MOVED"); break;
	case ComponentEvent.COMPONENT_RESIZED:
	    showLine("COMPONENT_RESIZED");break;
	case ComponentEvent.COMPONENT_HIDDEN:
	    showLine("COMPONENT_HIDDEN"); break;
	case ComponentEvent.COMPONENT_SHOWN:
	    showLine("COMPONENT_SHOWN"); break;
	}
    }
    
    /** Display Window events.  Note the special handling of WINDOW_CLOSING */
    public void processWindowEvent(WindowEvent e) {
	switch(e.getID()) {
	case WindowEvent.WINDOW_OPENED: showLine("WINDOW_OPENED"); break;
	case WindowEvent.WINDOW_CLOSED: showLine("WINDOW_CLOSED"); break;
	case WindowEvent.WINDOW_CLOSING: showLine("WINDOW_CLOSING"); break;
	case WindowEvent.WINDOW_ICONIFIED: showLine("WINDOW_ICONIFIED"); break;
	case WindowEvent.WINDOW_DEICONIFIED:
	    showLine("WINDOW_DEICONIFIED"); break;
	case WindowEvent.WINDOW_ACTIVATED:
	    showLine("WINDOW_ACTIVATED"); break;
	case WindowEvent.WINDOW_DEACTIVATED:
	    showLine("WINDOW_DEACTIVATED"); break;
	}
	
	// If the user requested a window close, quit the program.
	// But first display a message, force it to be visible, and make
	// sure the user has time to read it.
	if (e.getID() == WindowEvent.WINDOW_CLOSING) {
	    showLine("WINDOW_CLOSING event received.");
	    showLine("Application will exit in 5 seconds");
	    // Force the updates to appear now.
	    update(this.getGraphics());
	    // Wait five seconds
	    try {Thread.sleep(5000);} catch (InterruptedException ie) { ; }
	    // Exit now
	    System.exit(0);
	}
    }
    
    /** The list of lines to display in the window */
    protected Vector lines = new Vector();
    
    /** Add a new line to the list of lines, and request redisplay */
    protected void showLine(String s) {
	if (lines.size() == 20) lines.removeElementAt(0);
	lines.addElement(s);
	repaint();
    }

    /** This method repaints the text in the window */
    public void paintComponent(Graphics g) {
	for(int i = 0; i < lines.size(); i++)
	    g.drawString((String)lines.elementAt(i), 20, i*16 + 50);
    }

    public boolean isOpaque() { return false; }
}