Action Listener problem

[mehnihma]

Can you help me with one problem,

I dont know how to invoke action op menu not the menu item?

I have File and Help menus and I need to invoke action when the Help menu is pressed but dont understand how, I know how to do in on MenuItem but same thing does not work on menu?

// menu 2

     menu2 = new JMenu("Help");
     menu2.setMnemonic('H');
     menuBar.add(menu2);     

menu2.addActionListener(this);

public void actionPerformed(ActionEvent e)
  {
      if (e.getActionCommand().equals("Exit"))
      {
         System.exit(0);
      }
      else if (e.getSource() == menu2) {
         JOptionPane.showMessageDialog(frame, "Protected Viewer\n Version 2.1\n January 15, 2011\n 218", "About Protected View", JOptionPane.INFORMATION_MESSAGE);           
         }

if i do this for menu item like Exit it works but in menu it does not work?

[mKorbel]

JMenu isn't designated to invoke any action, JMenu is container nested JMenuItem(s), sure there are two/three choices how to determine if JMenu is visible / hidden

my question Why do you want/need to listening for that, for why reason

[mehnihma]

That is asked in the lab that I need to do

[mKorbel]

that would be big mistake in the lab, only too higher/est applications needed listening for that and in other hands talking about wrong desing

there are some issue with Focus, ButtonModel and another for_your_lab_non_important ZOO, possible listeners are

- MenuListener

- FocusListener

- Property/ChangeListener

for me every a.m. returns same results

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

public class ActionExample {

    public static void main(String[] args) {
        Action sample = new SampleAction();
        JMenu menu = new JMenu("Menu");
        menu.setMnemonic(KeyEvent.VK_M);
        menu.add(sample);
        menu.addMenuListener(new SampleMenuListener());
        JToolBar tb = new JToolBar();
        tb.add(sample);
        JTextField field = new JTextField(10);
        field.setAction(sample);
        JFrame f = new JFrame("ActionExample");
        JMenuBar mb = new JMenuBar();
        mb.add(menu);
        f.setJMenuBar(mb);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(tb, BorderLayout.NORTH);
        f.getContentPane().add(field, BorderLayout.SOUTH);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    private ActionExample() {
    }
}

class SampleMenuListener implements MenuListener {

    @Override
    public void menuSelected(MenuEvent e) {
        System.out.println("menuSelected");
    }

    @Override
    public void menuDeselected(MenuEvent e) {
        System.out.println("menuDeselected");
    }

    @Override
    public void menuCanceled(MenuEvent e) {
        System.out.println("menuCanceled");
    }
}

class SampleAction extends AbstractAction {

    private static final long serialVersionUID = 1L;

    public SampleAction() {
        super("Sample");
        putValue(ACCELERATOR_KEY, KeyStroke.getKeyStroke("alt S"));
        putValue(MNEMONIC_KEY, new Integer(KeyEvent.VK_S));
        putValue(SHORT_DESCRIPTION, "Just a sample action");
    }

    @Override
    public void actionPerformed(ActionEvent evt) {
        System.out.println("sample...");
    }
}

[DavidKroukamp]

That is asked in the lab that I need to do

check this out not the best but its something, as mKorbel said and i agree java never intended a menu to be used like that, and its not a good question at all for the lecturers to ask but here:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package menu;

import javax.swing.*;
import java.awt.event.*;

public class Menu extends JFrame {

    public Menu() {
        super("Menu example");

        final JMenu file = new JMenu("File");
        file.setMnemonic('F');
        JMenuItem newItem = new JMenuItem("New");
        newItem.setMnemonic('N');
        file.add(newItem);
        JMenuItem openItem = new JMenuItem("Open");
        openItem.setMnemonic('O');
        file.add(openItem);
        JMenuItem exitItem = new JMenuItem("Exit");
        exitItem.setMnemonic('x');
        file.add(exitItem);
        //here i add an item listner to File/file
        file.addItemListener(new ItemListener() {

            int count = 0;

            @Override
            public void itemStateChanged(ItemEvent e) {
                if (count == 2) {
                    count = 0;
                }
                if (count != 1) {
                    if (isActive()) {
                        System.out.println("File is pressed");
                    }
                }
                count++;
            }
        });
        //adding action listener to menu items
        newItem.addActionListener(
                new ActionListener() {

                    @Override
                    public void actionPerformed(ActionEvent e) {
                        System.out.println("New is pressed");
                    }
                });
        openItem.addActionListener(
                new ActionListener() {

                    @Override
                    public void actionPerformed(ActionEvent e) {
                        System.out.println("Open is pressed");
                    }
                });
        exitItem.addActionListener(
                new ActionListener() {

                    @Override
                    public void actionPerformed(ActionEvent e) {
                        System.out.println("Exit is pressed");
                    }
                });
        JMenuBar bar = new JMenuBar();
        setJMenuBar(bar);
        bar.add(file);

        getContentPane();
        setSize(200, 200);
        setVisible(true);
    }

    public static void main(String[] args) {
        Menu app = new Menu();
        app.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}

[mehnihma]

but how to do it with

public void menuSelected(MenuEvent e) {
         System.out.println("menuSelected");
      }

in a separate class?

[DavidKroukamp]

but how to do it with

public void menuSelected(MenuEvent e) {
         System.out.println("menuSelected");
      }

in a separate class?

is it not already in a separate class?:

class SampleMenuListener implements MenuListener {
 
    @Override
    public void menuSelected(MenuEvent e) {
        System.out.println("menuSelected");
    }
 
    @Override
    public void menuDeselected(MenuEvent e) {
        System.out.println("menuDeselected");
    }
 
    @Override
    public void menuCanceled(MenuEvent e) {
        System.out.println("menuCanceled");
    }
}

only difference is its in a nested class... so just add public class SampleMenuListener implements... and you can put it in a separate class in the package

[mehnihma]

i have a class helpmenulistiner

public class help implements ActionListener implements MenuListener

how can I do that?

[DavidKroukamp]

i have a class helpmenulistiner

public class help implements ActionListener implements MenuListener

how can I do that?

public class help implements ActionListener, MenuListener

[mehnihma]

i get this error

HelpListener.java:19: cannot find symbol
symbol: class MenuListener
public class HelpListener implements ActionListener, MenuListener {

[mehnihma]

import java.awt.Component;
import java.awt.event.*;
import java.awt.event.ActionListener;
import javax.swing.*;

/**
 * The listener interface for receiving help events.
 *
 * @see HelpEvent
 */
   public class HelpListener implements ActionListener, MenuListener   {

   /** The exit2 and about menu Items. */
      private JMenuItem about2, exit2;

   /** The frame. */
      private JFrame frame;

   /**
    * default constructor for help button.
    *
    * @param about2 the about button
    * @param exit2 the exit button
    */
      public HelpListener(JMenuItem about2, JMenuItem exit2) {

         this.about2 = about2;
         this.exit2 = exit2;
      }

   /**
    * indicates that a meaningful action occurred.
    *
    * @param e the e
    * @e Action Listener action when button pressed
    */
      @Override
      public void actionPerformed(ActionEvent e) {

         if (e.getActionCommand().equals("Exit"))
         {
            System.exit(0);
         }

         else if (e.getActionCommand().equals("About")) {
            JOptionPane.showMessageDialog(frame,"Protected Text Viewer\n Version 2.1\n February 5, 2011\n M 218", "About Protected View", JOptionPane.INFORMATION_MESSAGE);
            System.out.println("M");
         }
      }

      @Override
      public void menuSelected(MenuEvent e) {
         System.out.println("menuSelected");
      }

      @Override
      public void menuDeselected(MenuEvent e) {
         System.out.println("menuDeselected");
      }

      @Override
      public void menuCanceled(MenuEvent e) {
         System.out.println("menuCanceled");
      }
   }// end class

[DavidKroukamp]

Import these 2:

import javax.swing.event.MenuEvent;
import javax.swing.event.MenuListener;