Resize problem with JMenuBar

[Balasubramanian Chandrasekaran]

I am working under Windows OS, the default behavior while resizing application under windows is to bring the menu downwards if it doesn't fit the size. (Please refer the attachment Expected.jpg) where i tried resizing the Eclipse IDE window which shows the menu perfectly and all the menu's are accessible

Wherein if i try to resize the JFrame which i have created using the code below

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

public class Test
{
	public static void main(String args[])
	{
		JFrame frame = new JFrame("Test Frame");
		JMenuBar menuBar = new JMenuBar();
		frame.setJMenuBar(menuBar);
		JMenu Test1 = new JMenu();
		menuBar.add(Test1);
		Test1.setText("Test1");
		JMenu Test2 = new JMenu();
		menuBar.add(Test2);
		Test2.setText("Test2");
		JMenu Test3 = new JMenu();
		menuBar.add(Test3);
		Test3.setText("Test3");
		JMenu Test4 = new JMenu();
		menuBar.add(Test4);
		Test4.setText("Test4");
		JMenu Test5 = new JMenu();
		menuBar.add(Test5);
		Test5.setText("Test5");
		JMenu Test6 = new JMenu();
		menuBar.add(Test6);
		Test6.setText("Test6");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.pack();
		frame.setVisible(true);
	}
}

I can see that the menu is no longer usable (Please refer Result.jpg in attachment). How can i prevent this from happening. I tried using FlowLayout on JMenuBar but still i can't see any difference.

[Balasubramanian Chandrasekaran]

Finally, searching the bug tracker of java revealed a similar issue which i am facing and i tried out the code provided in the bug tracker

Old Java Bug

and that one seemed to work if i have only the menu aligned in the left of the JFrame. When i tried adding a JLabel onto JMenuBar using Box.createHorizontalGlue() to align only the JLabel to the right the custom layout code is not working as it uses the FlowLayout wherein the Glue will work perfectly under BoxLayout only. So any idea how to over come this situation.

Here is the updated code which i am trying now

import java.awt.*;
import java.awt.event.*;

import javax.swing.Box;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JTextArea;

public class LayoutTest
{
	public static void main(String args[])
	{
		JFrame mainFrame = new JFrame("Test mainFrame");
		JMenuBar menuBar = new JMenuBar();
		menuBar.setLayout(new CustomJMenuBarLayout(menuBar));
		mainFrame.setJMenuBar(menuBar);
		JMenu fileMenu = new JMenu();
		fileMenu.setText("File");
		menuBar.add(fileMenu);
		JMenu editMenu = new JMenu();
		editMenu.setText("Edit");
		menuBar.add(editMenu);
		JMenu formatMenu = new JMenu();
		formatMenu.setText("Format");
		menuBar.add(formatMenu);
		JMenu optionMenu = new JMenu();
		optionMenu.setText("Options");
		menuBar.add(optionMenu);
		JMenu helpMenu = new JMenu();
		helpMenu.setText("Help");
		menuBar.add(helpMenu);
		menuBar.add(Box.createRigidArea(new Dimension(30,0)));
		JLabel cusMsg = new JLabel();
		cusMsg.setText("My custom message goes here, it must align to right");
		menuBar.add(cusMsg);
		mainFrame.add(new JTextArea(30,100));
		mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		mainFrame.pack();
		mainFrame.setVisible(true);
	}
}

class CustomJMenuBarLayout extends FlowLayout implements ComponentListener {
	private static final long serialVersionUID = 1L;
	private JMenuBar menubar;
	public CustomJMenuBarLayout(JMenuBar menubar) {
		super(FlowLayout.LEFT, 0, 0);
		this.menubar = menubar;
		menubar.addComponentListener( this );
	}
	public Dimension preferredLayoutSize(Container target) {
//		System.out.println("Preferred layout called");
		Insets insets = target.getInsets();
		int hgap = getHgap();
		int vgap = getVgap();
		
		Dimension targetSize = target.getSize();
 		//System.out.println("targetSize  =" + targetSize);
		int maxwidth = targetSize.width - (insets.left + insets.right + hgap*2);
		int nmembers = target.getComponentCount();
		int xPos = 0;
		int maxHeight = 0;
		Dimension dim = new Dimension(0, 0);
		for (int i = 0 ; i < nmembers ; i++) {
			Component m = target.getComponent(i);
			if (m.isVisible()) {
				Dimension d = m.getPreferredSize();
				//System.out.println("preferred size of #"+i+" is " + d);
				
				if (xPos + d.width > maxwidth && xPos != 0) {
					xPos = 0;
					dim.height += maxHeight + vgap;
					maxHeight = 0;
				}
				xPos += d.width;
				dim.width = Math.max( dim.width, xPos);
				
				xPos += hgap;
				
				maxHeight = Math.max( maxHeight, d.height);
			}
		}
		dim.height += maxHeight + vgap;
		dim.width += insets.left + insets.right ;
		dim.height += insets.top + insets.bottom;
		//System.out.println("returning dim = "+ dim + "\n");
		return dim;
    }
	
    public Dimension minimumLayoutSize(Container target) {
		return preferredLayoutSize(target);
	}
	// Component Listeners
 	public void componentHidden( ComponentEvent e) {
 	}
 	public void componentMoved( ComponentEvent e) {
 	}
 	public void componentShown( ComponentEvent e) {
 	}
 	public void componentResized( ComponentEvent e) {
 	}
}

[Rob Camick]

Create a panel that contains 2 menubars. One that can wrap and one that can't.

Something like the following. This examples uses the Wrap Layout which probably does the same thing as your CustomJMenuBarLayout, but as the class name implies it is more general. Choose whichever layout you want to use.

import javax.swing.*;
import java.awt.*;

public class MenuBarTest2
{
	public static void main(String[] args)
	{
		JMenuBar main = new JMenuBar();
		WrapLayout layout = new WrapLayout(WrapLayout.LEFT, 0, 0);
		main.setLayout( layout );
		JMenu fileMenu = new JMenu("File");
		fileMenu.add("File1");
		main.add(fileMenu);
		main.add( new JMenu("Menu2") );
		main.add( new JMenu("Menu3") );
		main.add( new JMenu("Menu4") );
		main.add( new JMenu("Menu5") );
		main.add( new JMenu("Menu6") );
		main.add( new JMenu("Menu7") );
		main.add( new JMenu("Menu8") );

		JMenuBar right = new JMenuBar();
		JMenu helpMenu = new JMenu("Help");
//		helpMenu.setVerticalAlignment(JMenuItem.TOP);
		helpMenu.add( new JMenuItem("Help1") );
		right.add(helpMenu);

		JPanel menuPanel = new JPanel( new BorderLayout() );
		menuPanel.add(main, BorderLayout.CENTER);
		menuPanel.add(right, BorderLayout.EAST);

		JFrame frame = new JFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.add(menuPanel, BorderLayout.NORTH);
		frame.setSize(500, 200);
		frame.setLocationRelativeTo( null );
		frame.setVisible(true);
	}
}

[Balasubramanian Chandrasekaran]

Rob Camick - Thanks for your reply

I tried out your code and found that it is working perfectly fine with the JMenu Help laid at the right end of JMenuBar. But, when i tried to change your code to meet my requirement of placing a JLabel at the right end i end up with another problem.

I took your code and then replaced Help - JMenu with a JLabel

            .....
            main.add( new JMenu("Menu7") );  
            main.add( new JMenu("Menu8") );  
      
            JMenuBar right = new JMenuBar();  
            JLabel helpMenu = new JLabel("Custom message at the right side of JFrame");  
            //helpMenu.setVerticalAlignment(JMenuItem.TOP);  
            //helpMenu.add( new JMenuItem("Help1") );  
            right.add(helpMenu);  
      
            JPanel menuPanel = new JPanel( new BorderLayout() );  
            menuPanel.add(main, BorderLayout.CENTER);  
            menuPanel.add(right, BorderLayout.EAST);
            .....

When i run this code initially it came up well (Attachment Step1.jpg) then i tried resizing to increase the size of JFrame which also worked perfectly (Attachment Step2.jpg) then i tried resizing to reducing the size of JFrame and found that the JLabel which was added is causing the JMenu to disappear(Attachment Step3.jpg)

I tried the same operation with native windows application which does a reverse case of hiding the Label. So can you tell me your suggestion to make the same for this JFrame as well. If i try to reduce the size of the JFrame then the JLabel can be hidden but the JMenu should appear.

And finally you got a nice blog post explaining the issue and can i use your WrapLayout.java in my code provided i will include your blog URL in the code.

[Rob Camick]

Add a ComponentListener to the panel. On the componentResized() event you need to do a calculation that determines it the label should be visible or not based on the width of the panel the label and the menu items.

[Balasubramanian Chandrasekaran]

Rob i will try out your suggestion.