The problem:
My code
Panel Class:
import javax.swing.*;
import java.awt.*;
public class MainFramePanel extends JPanel {
public static final int WIDTH = 1700, HEIGHT = 900;
private final JMenuBar menuBar = new JMenuBar();
private final JMenu fileMenu = makeFileMenu();
private MainFramePanel() {
this.setPreferredSize(new Dimension(WIDTH, HEIGHT));
this.setLayout(new BorderLayout());
menuBar.add(fileMenu);
this.add(menuBar, BorderLayout.NORTH);
}
private JMenu makeFileMenu() {
JMenu menu = new JMenu();
JMenuItem newFile = new JMenuItem("New"),
openFile = new JMenuItem("Open"),
saveFile = new JMenuItem("Save"),
exportFile = new JMenuItem("Export As"),
exit = new JMenuItem("Exit");
menu.add(newFile); menu.add(openFile);
menu.addSeparator();
menu.add(saveFile); menu.add(exportFile);
menu.addSeparator();
menu.add(exit);
return menu;
}
private static final MainFramePanel INSTANCE = new MainFramePanel();
public static MainFramePanel getInstance() {
return INSTANCE;
}
}
Frame Class:
import javax.swing.*;
public class MainFrame extends JFrame {
private MainFrame() {
super("My Program");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setContentPane(MainFramePanel.getInstance());
this.pack();
this.setLocationRelativeTo(null);
}
private static final MainFrame INSTANCE = new MainFrame();
public static MainFrame getInstance() {
return INSTANCE;
}
}
I tried to set different BorderLayout parameters, I thought if I increased vgap, the menu bar would move down, but this didn't. I tried to do it through setBounds without using layout, but then the menu bar disappeared altogether. I tried using frame.setJMenuBar(), but I ran into the same problem.
By default, the height of the JMenuBar is determined by getPreferredSize
which tries to fit all the components as required. Since your JMenu doesn't have a name, the JMenuBar is like - "well since you don't have any text, I'll make myself the minimum size so I don't occupy unnecessary space". So to fix this, give your JMenu a name as shown below.
private JMenu makeFileMenu() {
JMenu menu = new JMenu();
menu.setName("File");
JMenuItem newFile = new JMenuItem("New"),
openFile = new JMenuItem("Open"),
saveFile = new JMenuItem("Save"),
exportFile = new JMenuItem("Export As"),
exit = new JMenuItem("Exit");
menu.add(newFile);
menu.add(openFile);
menu.addSeparator();
menu.add(saveFile);
menu.add(exportFile);
menu.addSeparator();
menu.add(exit);
return menu;
}
Learn how to use a JMenu if you're confused.