Remove menu item when internal frame is closed

[Sylvia Allen]

I have this app that has a JFrame with a menu, and some JInternalFrames inside that. Each JInternalFrame has its own menuitem on the menu. How can I get the menuitem to go away when its JInternalFrame is closed? I tried to find this information on the Sun tutorial site but couldn't find it. I tried several ways already but nothing has worked. A code snippet would be very much appreciated.
- SA

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Sylvia Allen
[email protected]

[Manfred Leonhardt]

Hi Sylvia,
The code below doesn't do exactly what you want. But it might give you the general idea of menuItem add/remove.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
//
// Demo for dynamically adding checkboxmenuitems.
//  
public class JDynMenu extends JFrame implements ActionListener
{
  private JMenu windowMenu;
  private int numWindows = 1;
  private JPanel topPanel;
  //
  // Constructor for demo class.
  //
  public JDynMenu()
  {
    setSize( 700, 200 );
    addWindowListener(
      new WindowAdapter()
      {
        public void windowClosing( WindowEvent we )
        {
          System.exit( 0 );
        }
      });
    // Create Window menu with one item.
    JMenuBar mb = new JMenuBar();
    windowMenu = new JMenu( "Window" );
    JCheckBoxMenuItem mi = new JCheckBoxMenuItem( "Window0", true );
    windowMenu.add( mi );
    mb.add( windowMenu );
    setJMenuBar( mb );
    // Add buttons for adding and quitting.
    Panel p = new Panel();
    Button b1 = new Button( "Add" );
    b1.setActionCommand( "Add" );
    b1.addActionListener( this );
    Button b2 = new Button( "Quit" );
    b2.setActionCommand( "Quit" );
    b2.addActionListener( this );
    p.add( b1 );
    p.add( b2 );
    getContentPane().add( p, BorderLayout.SOUTH );
    // Add panel to north to hold new buttons (give one as default)
    topPanel = new JPanel();
    Button b = new Button( "Window0" );
    b.addActionListener( this );
    topPanel.add( b );
    getContentPane().add( topPanel, BorderLayout.CENTER );
  }
  //
  // Handle all button callbacks.
  //
  public void actionPerformed( ActionEvent ae )
  {
    String cmd = ae.getActionCommand();
    if( cmd.equals( "Quit" ) )
    {
      System.exit( 0 );
    }
    else if( cmd.equals( "Add" ) )
    {
      String newName = "Window" + numWindows;
      // Add button to topPanel first.
      Button b = new Button( newName );
      b.addActionListener( this );
      topPanel.add( b );
      topPanel.doLayout();
      // Add associated checkbox to window menu.
      addMenuCheckBox( newName );
      ++numWindows;
    }
    else if( cmd.equals( "Delete" ) )
    {
      String lastName = "Window" + --numWindows;
      deleteMenuCheckBox( lastName );
    }
    else
    {
      // Handle button specifying menu item to check.
      Object ob = ae.getSource();
      if( ob instanceof Button )
      {
        selectMenuCheckBox( ((Button)ob).getLabel() );
      }
    }
  }
  //
  // Clear all checkboxes inside menu.
  //
  public void clearMenuCheckBoxes()
  {
    for( int i = 0; i < windowMenu.getItemCount(); ++i )
    {
      JMenuItem c = windowMenu.getItem( i );
      if( c instanceof JCheckBoxMenuItem )
      {
        ((JCheckBoxMenuItem)c).setState( false );
      }
    }
  }
  //
  // Add new checkbox menu item.
  //
  public void addMenuCheckBox( String s )
  {
    clearMenuCheckBoxes();
    // Add new one and default it to set.
    JCheckBoxMenuItem cmi = new JCheckBoxMenuItem( s, true );
    windowMenu.add( cmi );
  }
  //
  // Delete checkbox menu item.
  //
  public void deleteMenuCheckBox( String s )
  {
    clearMenuCheckBoxes();
    // Delete it and set default to one before.
    windowMenu.remove( findMenuCheckBox( s ) );
  }
  //
  // Find which position checkbox is in menu.
  //
  public int findMenuCheckBox( String s )
  {
    int match = -1;    
    for( int i = 0; i < windowMenu.getItemCount(); ++i )
    {
      mi = windowMenu.getItem( i );
      if( mi instanceof JCheckBoxMenuItem )
      {
        if( ((JCheckBoxMenuItem)mi).getText().equals( s ) )
        {
          match = i;
          break;
        }
      }     
    }
    return( match );
  }
  public void selectMenuCheckBox( String s )
  {
    int match = findMenuCheckBox( s );
    if( match >= 0 )
    {
      // Clear all check boxes
      clearMenuCheckBoxes();
      // Set the specified one
      JMenuItem mi = windowMenu.getItem( match );
      ((JCheckBoxMenuItem)mi).setState( true );
    }
  }
  public static void main(String[] args) 
  {
    JDynMenu jm = new JDynMenu();
    jm.setVisible( true );
  }
}

Enjoy,
Manfred.

[Gregg Bolinger]

Hi, a way to do this is two ways.
1. Add a InternalFrame Listener and listen for the close event. On that event do myMenu.remove(myMenuItem)
2. Another way would be do disable the close option on the InternalFrame in the upper right corner and create a Close Button somewhere on the InternalFrame. And then add a Listener to the button and do the same as #1 above when the button is pressed but also do a dispose() for the Internal Frame to get rid of it.
Hope that helps

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Happy Coding,
Gregg Bolinger