How to Set Vertical Separators for JMenuItems

Question

I can only set horizontal separator to my code , how to set vertical one ? Similar to this http://jade-cheng.com/hpu/2012-spring/csci-2912/assignment-5/blueprint-2.png

    file.add(newMenuItem);
    file.add(openMenuItem);
    file.add(saveMenuItem);
    file.add(subMenu);
    file.addSeparator();
    file.add(exitMenuItem);

Answer 1

Vertical separator in JMenuItem? The only thing which comes to my mind and which you can treat as a JSeparator is something like below:

But this left "JSeparator" is not an extra added JSeparator, but depends on LookAndFeel.

Below you see the same JFrame with the same JMenuBar but with different lookandfeel:

The code for both screens is exactly the same, but executed with different look and feels:

public class NewClass extends JFrame {

    public NewClass() throws HeadlessException {
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("File");
        menuBar.add(menu);
        menu.add(new JMenuItem("Open..."));
        menu.add(new JMenuItem("Save"));
        menu.add(new JMenuItem("Save as..."));
        menu.addSeparator();
        menu.add(new JMenuItem("Delete"));

        setJMenuBar(menuBar);
        setSize(new Dimension(500,500));
        setVisible(true);
    }

    public static void main(String[] args) {
        try {
           //UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
           //UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
           UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());      
           new NewClass();
        } catch (ClassNotFoundException ex) {
          Logger.getLogger(NewClass.class.getName()).log(Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
          Logger.getLogger(NewClass.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
          Logger.getLogger(NewClass.class.getName()).log(Level.SEVERE, null, ex);
        } catch (UnsupportedLookAndFeelException ex) {
          Logger.getLogger(NewClass.class.getName()).log(Level.SEVERE, null, ex);
        }
    }   
}

Note, that

menu.add(new JSeparator(JSeparator.VERTICAL));

will not generate any separator at all (you can try)

Answer 2

As already pointed out by @guitar_freak, some LayoutManagers give you this effect for free, whereas others do not. If you wanted this effect for any LM, you'll have to roll up your sleeves a bit.

A JMenu is an AbstractButton that has no layout by default. When you add something to a JMenu, you're actually adding it to the menu's internal JPopupMenu, which has a DefaultMenuLayout (subclass of BoxLayout) as it's layout by default.

Things to try: write your own MenuItemUI to install on the JMenu, or subclass the JMenu to use a JPopupMenu with a different LayoutManager. I haven't tried either so I'm not sure which is correct.

Personally, I'd just leave it up to the L&F as @guitar_freak suggested. It seems to much work for too little gain, but ultimately, only you can decide that.

Answer 3

I think this is what you're looking for:

file.add(new JSeparator(SwingConstants.VERTICAL));