Swing and Nimbus: Replace background of JPopupMenu (attached to JMenu)

Question

Nimbus often looks great, but for certain color combinations the result is non-optimal. In my case, the background of a JPopupMenu does not fit, which is why I

Answer 1

One way to do it is to color the background of the individual JMenuItems and make them opaque:

JMenuItem a = new JMenuItem("A");
a.setOpaque(true);
a.setBackground(Color.GREEN);

Then give the menu itself a green border to fill the rest:

menu.setBorder(BorderFactory.createLineBorder(Color.GREEN));

There may be an easy/more straightforward way out there, but this worked for me.

Answer 2

not the whole story - but looks like setting the opacity of menu/items to true partly solves it (as @Derek Richard already did for a item created under full application control):

UIDefaults ui = UIManager.getLookAndFeelDefaults();
ui.put("PopupMenu.background", GREEN);
ui.put("Menu.background", GREEN);
ui.put("Menu.opaque", true);
ui.put("MenuItem.background", GREEN);
ui.put("MenuItem.opaque", true);

and so on, for all types of items like radioButton/checkBox.

This still leaves a upper/lower grey area - don't know which part is responsible for that drawing. Removing the margin helps at the price of looking squeezed

// this looks not so good, but without the margins above/below are still grey
ui.put("PopupMenu.contentMargins", null);

There's a list of property keys in the tutorial.

Answer 3

• there are a few mistakes in both answers

• and above mentioned way to required to override most UIDeafaults that have got impact to the another JComponents and its Color(s)

• Nimbus has own Painter, one example for that ...

from code

import com.sun.java.swing.Painter;
import java.awt.*;
import javax.swing.*;

public class MyPopupWithNimbus {

    public MyPopupWithNimbus() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(200, 200);
        JPanel panel = new JPanel(new BorderLayout());
        panel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
        JList list = new JList();
        panel.add(list);
        frame.getContentPane().add(panel);
        JPopupMenu menu = new JPopupMenu();
        menu.add(new JMenuItem("A"));
        menu.add(new JMenuItem("B"));
        menu.add(new JMenuItem("C"));
        JMenu jmenu = new JMenu("D");
        jmenu.add(new JMenuItem("E"));
        menu.add(jmenu);
        frame.setVisible(true);
        menu.show(frame, 50, 50);
    }

    public static void main(String[] args) {

        try {
            for (UIManager.LookAndFeelInfo laf : UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(laf.getName())) {
                    UIManager.setLookAndFeel(laf.getClassName());
                    UIManager.getLookAndFeelDefaults().put("PopupMenu[Enabled].backgroundPainter",
                            new FillPainter(new Color(127, 255, 191)));
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                MyPopupWithNimbus aa = new MyPopupWithNimbus();
            }
        });
    }
}

class FillPainter implements Painter<JComponent> {

    private final Color color;

    FillPainter(Color c) {
        color = c;
    }

    @Override
    public void paint(Graphics2D g, JComponent object, int width, int height) {
        g.setColor(color);
        g.fillRect(0, 0, width - 1, height - 1);
    }
}