Question

I have a problem when i want insert a separator with JSeparator for Java Swing application. In point of fact, I have this problem just when i run my program on Mac, i haven’t it on windows or linux. The separator is incorrectly placed, the text is strikethrough. Does anyone know why?

My code :

JMenuItem fileItem = new JMenuItem("Close");
KeyStroke ...
fileItem.add(new JSeparator(JSeparator.HORIZONTAL),BorderLayout.LINE_START);

Screenshot :

Answer 1

Basically your code right now shows that you are assuming JMenuItem has a default BorderLayout, which could be true (but I dont think so).

Though the root problem is you are adding the JSeparator to the JMenuItem when in fact you should add it to the JMenu which contains the various JMenuItems via JMenu#addSeparator(). See How to Use Separators for more.

You should be doing something like:

JMenu menu=new JMenu();

JMenuItem item1=new JMenuItem("something 1");
JMenuItem item2=new JMenuItem("something 1");

menu.add(item1);
menu.addSeparator();//lets add that separator
menu.add(item2);

giving you something like:

UPDATE:

Here is an example:

import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.SwingUtilities;

public class Test {

    public Test() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JMenuBar menuBar=new JMenuBar();

        JMenu menu = new JMenu("File");
        JMenu menu2 = new JMenu("Else");

        JMenuItem item1 = new JMenuItem("something 1");
        JMenuItem item2 = new JMenuItem("something 2");
        JMenuItem item3 = new JMenuItem("else 1");
        JMenuItem item4 = new JMenuItem("else 2");

        menu2.add(item3);
        menu2.addSeparator();//lets add that separator
        menu2.add(item4);

        menu.add(menu2);
        menu.add(item1);
        menu.addSeparator();//lets add that separator
        menu.add(item2);

        menuBar.add(menu);

        frame.setJMenuBar(menuBar);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String args[]) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Test();
            }
        });
    }
}