I have a simple program that should print a JFrame that contains a JScrollPane. I'd like to print the whole thing, but when I try to do so, I get the following exception:

Exception occurred during event dispatching:
java.lang.NullPointerException
        at java.awt.Rectangle.intersects(Rectangle.java:383)
        at java.awt.Container.print(Container.java:769)
        at sun.awt.motif.MComponentPeer.print(MComponentPeer.java:172)
        at sun.awt.motif.MPanelPeer.print(MPanelPeer.java:41)
        at sun.awt.motif.MFramePeer.print(MFramePeer.java:174)
        at java.awt.Component.printAll(Component.java:1395)
        at ScrollerTest.print(ScrollerTest.java:85)
        at QWSTKey.keyPressed(ScrollerTest.java:109)
        at java.awt.Component.processKeyEvent(Component.java:2247)
        at com.sun.java.swing.JFrame.processKeyEvent(JFrame.java:106)
        at java.awt.Component.processEvent(Component.java:2138)
        at java.awt.Container.processEvent(Container.java:894)
        at java.awt.Window.processEvent(Window.java:315)
        at java.awt.Component.dispatchEventImpl(Component.java:1764)
        at java.awt.Container.dispatchEventImpl(Container.java:939)
        at java.awt.Window.dispatchEventImpl(Window.java:443)
        at java.awt.Component.dispatchEvent(Component.java:1704)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:63)
^

Here's the program


File 1

// ScrollerTest.java

/**
 * <B>ScrollerTest</B> is a simple class that has a main. Used to test things.
 * in libraries;
 *
 * @version $Id$
 *
 *
 */

import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Toolkit;
import java.awt.PrintJob;

import java.awt.event.InputEvent;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

import com.sun.java.swing.JFrame;

import com.sun.apps.frameworks.foundation.LFAssert;

import ScrollPanePanel;

import com.sun.java.swing.UIManager;

public class ScrollerTest
    extends
Container
{
//
// Protected Constants
//
    static protected int WIDTH = 500;
    static protected int HEIGHT = 400;

    static protected String TITLE = "ScrollerTest";

//
// Class Variables
//

//
// Instance Variables
//

static protected JFrame frame = null;

//
// General Methods
//

static public void main(String args[])
{
    LFAssert.setEnabled(true);

    frame = new JFrame(ScrollerTest.TITLE);
    frame.setForeground(Color.lightGray);

    Dimension screenSize, initialSize = new Dimension(WIDTH, HEIGHT);

    screenSize = Toolkit.getDefaultToolkit().getScreenSize();
    
    frame.setSize(initialSize);
    frame.setLocation(screenSize.width/2 - initialSize.width/2,
screenSize.height/2 - initialSize.height/2);
    frame.getContentPane().add(new ScrollPanePanel());
    frame.addKeyListener(new QWSTKey());
    frame.show();
}

static public void print()
{
    PrintJob pj = Toolkit.getDefaultToolkit().getPrintJob(frame,
"ScrollerTest",
null);
    Graphics pg = pj.getGraphics();
    frame.printAll(pg);
    return;
}

} // end of class ScrollerTest

class QWSTKey extends KeyAdapter
{

public void keyPressed(KeyEvent e)
{
    
    int keyCode = e.getKeyCode();
    
    switch (keyCode) {
    case KeyEvent.VK_ENTER:
break;
    case KeyEvent.VK_BACK_SPACE:
// delete selection;
break;
    case KeyEvent.VK_DELETE:
// delete selection;
break;
    case KeyEvent.VK_TAB:
ScrollerTest.print();
break;
    case KeyEvent.VK_LEFT:
break;
    case KeyEvent.VK_RIGHT:
break;
    case KeyEvent.VK_UP:
break;
    case KeyEvent.VK_DOWN:
break;
    case KeyEvent.VK_ALT:
    case KeyEvent.VK_CAPS_LOCK:
    case KeyEvent.VK_CONTROL:
    case KeyEvent.VK_META:
    case KeyEvent.VK_SHIFT:
// a modifier key: ignore it
break;
    case KeyEvent.VK_UNDEFINED:
break;
    default:
break;
    }

}
} // end of class QWSTKey

File 2


import com.sun.java.swing.*;

import java.awt.*;
import java.awt.event.*;

/*
 * @version 1.12 10/06/97
 * @author Jeff Dinkins
 */
public class ScrollPanePanel extends JPanel {

    public ScrollPanePanel() {
        setLayout(new BorderLayout());
add("Center", new TigerScrollPane());
    }

}

class TigerScrollPane extends JScrollPane {

    private JLabel makeLabel(String name, String description) {
String filename = "images/" + name;
ImageIcon image = new ImageIcon(filename, description);
return new JLabel(image);
    }

    public TigerScrollPane() {
super();

JLabel horizontalRule = makeLabel("scrollpane/header.gif", "Horizontal ruler carved out of stone");
JLabel verticalRule = makeLabel("scrollpane/column.gif", "Vertical ruler carved out of stone");
JLabel tiger = makeLabel("BigTiger.gif","A rather fierce looking tiger");

JLabel cornerLL = makeLabel("scrollpane/corner.gif","Square chunk of stone (lower left)");
JLabel cornerLR = makeLabel("scrollpane/corner.gif","Square chunk of stone (lower right)");
JLabel cornerUL = makeLabel("scrollpane/corner.gif","Square chunk of stone (upper left)");
JLabel cornerUR = makeLabel("scrollpane/corner.gif","Square chunk of stone (upper right)");

setViewportView(tiger);
setRowHeaderView(verticalRule);
setColumnHeaderView(horizontalRule);

setCorner(LOWER_LEFT_CORNER, cornerLL);
setCorner(LOWER_RIGHT_CORNER, cornerLR);
setCorner(UPPER_LEFT_CORNER, cornerUL);
setCorner(UPPER_RIGHT_CORNER, cornerUR);
    }
    
    public Dimension getMinimumSize() {
return new Dimension(25, 25);
    }
    
    public boolean isOpaque() {
        return true;
    }
}

In addition, you need to have the following hierarchy in the same directory as the compiled .class files

 
./images:
BigTiger.gif scrollpane
 
./images/scrollpane:
01.gif 02s.gif 04.gif 05s.gif column.gif main.gif
01s.gif 03.gif 04s.gif 06.gif corner.gif
02.gif 03s.gif 05.gif 06s.gif header.gif


For your convenience I have placed all of this at

cd /net/arago.eng/ProjectsLocal/edburns/scratch/bugtraq

To use the program have JDK1.1.5, Swing0.6.1 in your classpath,

java ScrollerTest

Press the <TAB> key to pop up the print dialog. Fill it out, and press
the <PRINT> button.

I was requested to reopen this bug and I have done so.


ed.burns@Eng 1998-03-18