ActionListen didn't fire on JMenu

Question

I am fairly new java programming. I created a JMenu and add the actionlisten, but it didn't fire. The JPanel, jpCommentMainPane, is added to JFrame. Also the JFrame has its own menu bar and actionlistener. Would someone tell me how to make it work. Thanks in advance.

There is my code to add the JMenu into the JPanel:

jpCommentMainPane=new JPanel();         
jpCommentMainPane.setLayout(new BorderLayout(10,10));
JPanel totalCommentPane=new JPanel(new FlowLayout(FlowLayout.LEFT));
JPanel jpFindPane=new JPanel(new FlowLayout(FlowLayout.LEFT));      
totalCommentPane.setPreferredSize(new Dimension(rightPaneWidth,20));        
jpFindPane.add(sortMenu());  //add menubar
JPanel topPane=new JPanel();
topPane.setLayout(new BorderLayout());
topPane.add(jpFindPane, BorderLayout.SOUTH);
jpCommentMainPane.add(topPane, BorderLayout.NORTH);

There is the method to return the JMenuBar

//Create sort menu bar
private JMenuBar sortMenu(){

    JMenuBar menuBar=new JMenuBar();
    JMenu menu=new JMenu("Sort");
    JRadioButtonMenuItem menuItemType=new JRadioButtonMenuItem("Type");
    menu.add(menuItemType);
    JRadioButtonMenuItem menuItemPage=new  JRadioButtonMenuItem("Page");
    menu.add(menuItemPage);
    JRadioButtonMenuItem menuItemAuthor=new  JRadioButtonMenuItem("Author");
    menu.add(menuItemAuthor);
    JRadioButtonMenuItem menuItemDate=new  JRadioButtonMenuItem("Date");
    menu.add(menuItemDate);
    menu.addActionListener(new ActionListener(){            
    @Override
        public void actionPerformed(ActionEvent e){ 
             Utility.DisplayErrorMsg(pageErrorPrefix+ "line 145");
            String command=e.getActionCommand().trim().toUpperCase();
            if (command.equals(SortItem.TYPE)){
                pageSortBy=SortItem.TYPE;
            }else if (command.equals(SortItem.PAGE)){
                pageSortBy=SortItem.PAGE;
            }else if(command.equals(SortItem.TYPE)){
                pageSortBy=SortItem.TYPE;
            }else if(command.equals(SortItem.CREATOR)){
                pageSortBy=SortItem.CREATOR;
            }else if (command.equals(SortItem.DATE)){
                pageSortBy=SortItem.DATE;
            }

            getListCommentPane();

        }

    }

            );
    menuBar.add(menu);
    return menuBar;


}

Answer 1

JMenus need MenuListeners not ActionListeners to handle events. JMenuItems will use ActionListeners , however I'm not sure about JRadioButtonMenuItems.

One thing to try would be using inner classes for each JRadioButtonMenuItem.

For example, for the menuItemType

public class menuItemTypeListener implements ActionListener{
     public void ActionPerformed(ActionEvent ae){
         //Do Something here
     }
}

menuItemType.addActionListener(new menuItemTypeListener());

Answer 2

OK, I'm sure now. You can add an ActionListener to a JMenu, but unlike a JMenuItem, it has no effect. Instead if the JMenu object needs a listener, you should add a MenuListener to your JMenu.