Name: rv122619 Date: 08/20/2004

One of our products has demonstrated non-standard behaviour whereby a modal dialog that has no focusable components does not block key events and therefore allows menubar accelerators to run.

Current Behavior:
If you have a Modal Window open and try to access a menu bar item, via the keyboard(ALT + mnemonic) computer does not beep at user.

Beep, does occur with a mouse.

Expected Behavior:
When you try to access a menu bar item via keyboard with a Modal Window open, access should not be allowed and a beep should be provided to user.

Also, if you have a dialog with nothing in it to receive input focus (which is probably never the case), the modal dialog doesn't lock one out.

Source code that demonstrates issue and provides workaround:

import java.awt.BorderLayout;
import java.awt.Menu;
import java.awt.MenuBar;
import java.awt.MenuItem;
import java.awt.MenuShortcut;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.KeyStroke;
import javax.swing.WindowConstants;

public class TestFrame
         extends JFrame
{
   public static void main(String[] args)
   {
      boolean awtMenuBar = (args != null && args.length > 0 && args[0].equals("awt"));
      TestFrame frame = new TestFrame(awtMenuBar);
      frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }
   
   public TestFrame(boolean useAWTMenuBar)
   {
      setTitle("Test Frame");
      getContentPane().add(new JLabel("Test Frame"));
      
      if (useAWTMenuBar)
         setMenuBar(createAWTMenuBar());
      else
         setJMenuBar(createJMenuBar());
   }

   private MenuBar createAWTMenuBar()
   {
      MenuBar menuBar = new MenuBar();
      Menu menu = new Menu("File");
      menuBar.add(menu);
      
      MenuItem mi = new MenuItem("Show Focusable Dialog");
      mi.setShortcut(new MenuShortcut(KeyEvent.VK_S, false));
      mi.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent event) {
            showTestDialog(TestFrame.this, true);
         }
      });
      menu.add(mi);
      
      mi = new MenuItem("Show Non-Focusable Dialog");
      mi.setShortcut(new MenuShortcut(KeyEvent.VK_D, false));
      mi.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent event) {
            showTestDialog(TestFrame.this, false);
         }
      });
      menu.add(mi);
      return menuBar;
   }

   private JMenuBar createJMenuBar()
   {
      JMenuBar menuBar = new JMenuBar();
      JMenu menu = new JMenu("File");
      menuBar.add(menu);
      
      JMenuItem mi = new JMenuItem("Show Focusable Dialog");
      mi.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S, InputEvent.CTRL_MASK));
      mi.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent event) {
            showTestDialog(TestFrame.this, true);
         }
      });
      menu.add(mi);
      
      mi = new JMenuItem("Show Non-Focusable Dialog");
      mi.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_D, InputEvent.CTRL_MASK));
      mi.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent event) {
            showTestDialog(TestFrame.this, false);
         }
      });
      menu.add(mi);
      
      return menuBar;
   }

   public static void showTestDialog(JFrame frame, boolean addFocusableComp)
   {
      final JDialog dialog = new JDialog(frame, "Test Dialog", true);
      dialog.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
      if (addFocusableComp)
      {
         dialog.getContentPane().add(new JLabel("Test dialog with a focusable component."), BorderLayout.NORTH);
         dialog.getContentPane().add(new JButton("A Focusable Button"));
      }
      else
      {
         dialog.getContentPane().add(new JLabel("Test dialog with no focusable components."));

// // workaround 1
// SwingUtilities.invokeLater(new Runnable() {
// public void run() {
// dialog.getContentPane().requestFocus();
// }
// });

// // workaround 2
// dialog.addKeyListener(new java.awt.event.KeyAdapter() {
// public void keyPressed(java.awt.event.KeyEvent event) {
// event.consume();
// }
// public void keyReleased(java.awt.event.KeyEvent event) {
// event.consume();
// }
// public void keyTyped(java.awt.event.KeyEvent event) {
// event.consume();
// }
// });
      }

      dialog.pack();
      dialog.setLocationRelativeTo(frame);
      dialog.setVisible(true);
   }
}

If run normally (i.e. "java TestFrame") you will be able to bring up multiple non-focusable modal dialogs (using ctrl-D). If you pass "awt" as an argument, the code will use an AWT menubar instead of a Swing menubar and this problem doesn't occur.



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