Why won't my JMenuBar appear?

Question

I am trying to create a GUI in java, but JMenuBar does not give me a hard time for two days. Can someone please tell me why it does not appear?

import java.awt.*;
import javax.swing.*;
import javax.swing.JPanel;
import java.awt.event.*;
import java.awt.image.*;     
import java.io.*;
import java.util.Arrays;
import javax.imageio.ImageIO;

public class selectionFrame extends JFrame
 {
  Font name;
  Font title;

  public void setup() //can't use constructer because this isn't given a size until after it is constructed.
  { 
   //getContentPane().add(menuBar);
   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   getContentPane().setLayout(new FlowLayout());
   //getContentPane().add(j);

   setJMenuBar(createMenuBar());
   //getContentPane().add(createMenuBar());  
  }

  public JMenuBar createMenuBar()
  {
   JMenuBar menuBar;
   JMenu m_file;
   JMenuItem mi_save;
   JMenuItem mi_load;

   JMenu m_edit;
   JMenuItem mi_tileHeight;
   JMenuItem mi_tileWidth;

   menuBar = new JMenuBar();
   m_file = new JMenu("File");
   m_edit = new JMenu("Edit");

   mi_save = new JMenuItem("Save file", KeyEvent.VK_S);
   mi_load = new JMenuItem("Load file", KeyEvent.VK_L);
   mi_tileHeight = new JMenuItem("Set tile height", KeyEvent.VK_H);
   mi_tileWidth = new JMenuItem("Set tile width", KeyEvent.VK_W);

   menuBar.add(m_file);
   m_file.add(mi_save);
   m_file.add(mi_load);

   menuBar.add(m_edit);
   m_edit.add(mi_tileHeight);
   m_edit.add(mi_tileWidth);

   return menuBar;
  }

  public static void main(String[] args) //run
  { 
   selectionFrame sel = new selectionFrame();
   sel.setLocationRelativeTo(null);
   sel.setSize((int) 400 + (sel.getInsets().left + sel.getInsets().right),(int) 400  + (sel.getInsets().top + sel.getInsets().bottom));

   sel.setVisible(true);
   sel.setTitle("Tiles/Meta");
   sel.setResizable(false);
   sel.setFocusable(true);
   sel.getContentPane().setSize(sel.getSize());
   sel.setLocation((int) sel.getX() - (sel.getWidth()/2),(int) sel.getY() -  (sel.getHeight()/2));
   sel.setup();
   sel.repaint();

   } 
 }

Answer 1

You have a lot of extra code there.

public class SelectionFrame extends JFrame
{
    Font name;
    Font title;

    public SelectionFrame()
    {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setJMenuBar(createMenuBar());
    }

    public JMenuBar createMenuBar()
    {
        JMenuBar menuBar;
        JMenu m_file;
        JMenuItem mi_save;
        JMenuItem mi_load;

        JMenu m_edit;
        JMenuItem mi_tileHeight;
        JMenuItem mi_tileWidth;

        menuBar = new JMenuBar();
        m_file = new JMenu("File");
        m_edit = new JMenu("Edit");

        mi_save = new JMenuItem("Save file", KeyEvent.VK_S);
        mi_load = new JMenuItem("Load file", KeyEvent.VK_L);
        mi_tileHeight = new JMenuItem("Set tile height",
        KeyEvent.VK_H);
        mi_tileWidth = new JMenuItem("Set tile width",
        KeyEvent.VK_W);

        menuBar.add(m_file);
        m_file.add(mi_save);
        m_file.add(mi_load);

        menuBar.add(m_edit);
        m_edit.add(mi_tileHeight);
        m_edit.add(mi_tileWidth);

        return menuBar;
    }

    public void main( String args[] )
    {

        SelectionFrame sel = new SelectionFrame();
        sel.setLocationRelativeTo(null);
        sel.setSize(400 + (sel.getInsets().left + > sel.getInsets().right), 400
        + (sel.getInsets().top + sel.getInsets().bottom));

        sel.setTitle("Tiles/Meta");
        sel.setResizable(false);
        sel.setFocusable(true);

        sel.getContentPane().add( new JLabel( "Content", SwingConstants.CENTER),
         BorderLayout.CENTER );
        sel.setLocation(sel.getX() - (sel.getWidth() / 2), sel.getY() - >             (sel.getHeight() / 2));
        sel.setVisible(true);

    }
}

This is displayed using the menu bar and all. if you add your content to the CENTER of the content area (the default border layout), the center automatically fills the entire content area, you do not need to resize.

This appears as a window with a menu bar, and everything works fine.

What platform are you doing this on? I am in Vista, I get what I expect to see.

Answer 2

Java ? 1.6.0_10. invokeLater(), , :

public static void main(String[] args)
    {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                selectionFrame sel = new selectionFrame();
                sel.setLocationRelativeTo(null);
                sel.setSize((int) 400 + (sel.getInsets().left + sel.getInsets().right), 
                            (int) 400 + (sel.getInsets().top + sel.getInsets().bottom));
                sel.setTitle("Tiles/Meta");
                sel.setResizable(false);
                sel.setFocusable(true);
                sel.getContentPane().setSize(sel.getSize());
                sel.setLocation((int) sel.getX() - (sel.getWidth() / 2),
                                (int) sel.getY() - (sel.getHeight() / 2));
                sel.setup();
                sel.setVisible(true); // Follow Kendrick advice too.
            }
        });
    }

Answer 3

HAVE, JMenuBar JFrame. , .

, . .

Answer 4

, RootPane, tsk tsk. RootPane (., , http://download.java.net/jdk7/archive/b123/docs/api/javax/swing/JRootPane.html) , , , .

ContentPane , :

frame.getContentPane().setLayout(...);
frame.getContentPane().add(...);

... ( OP, , ), , JMenuBar - , .

Answer 5

, . ?

- SelectionFrame

EDIT: , , . , Swing, AWT.

, , , , , - .

Sun AWT-, ( () setVisible (true)), .

, swing , SelectionFrame.

50-50 , , .

Answer 6

sel.setVisible();

, ......

Answer 7

, sel.setVisible(true); pls sel.pack();

, setSize setPreferredSize, .

It is not directly related to your question, but still - using a good layout manager is a huge time and frustration when using Swing. MigLayout is just a great layout manager.