How can I override the default mousepressed background color of all JButtons into a darker shade of its current background color?

Say I have ten JButtons each with their own background color explicitly set.
Now, they all get the default mousepressed background color but how can I set it to be a shade darker of their respective background colors without doing it one by one?

I know that I can override the color in UIManager :

UIManager.put("Button.select", Color.RED);

Which I found here <https://stackoverflow.com/questions/14627223/how-to-change-a-jbutton-color-on-mouse-pressed>

But that will change it to a single color only. All of my buttons will get a red background when pressed.

Is there a way to make it something like:

UIManager.put("Button.select", JButton.getBackground().darker());

I'm trying to learn java swing so bear with my ignorance.

One way to do this, is to create your own ButtonUI. To avoid the hassle of reinventing the wheel, you can exend a subclass of ButtonUI.

For example BasicButtonUI like so:

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.util.Objects;
import java.util.Random;
import javax.swing.AbstractButton;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.plaf.basic.BasicButtonUI;
public class MainWithBasicButtonUI {
public static class SelectButtonUI extends BasicButtonUI {
protected Color selectColor;
public void setSelectColor(final Color selectColor) {
this.selectColor = Objects.requireNonNull(selectColor);
}
public Color getSelectColor() {
return selectColor;
}
@Override
protected void paintButtonPressed(final Graphics g,
final AbstractButton b){
if (b.isContentAreaFilled()) {
Dimension size = b.getSize();
g.setColor(getSelectColor());
g.fillRect(0, 0, size.width, size.height);
}
}
}
private static void createAndShowGUI() {
final int rows = 3, cols = 3;
final Color[] colors = new Color[]{Color.RED.brighter(), Color.GREEN.brighter(), Color.CYAN};
final JPanel buttons = new JPanel(new GridLayout(rows, cols, 2, 2));
final Random rand = new Random();
for (int i = 0; i < rows * cols; ++i) {
final JButton b = new JButton("Button");
b.setBackground(colors[rand.nextInt(colors.length)]);
final SelectButtonUI ui = new SelectButtonUI();
ui.setSelectColor(b.getBackground().darker());
b.setUI(ui);
buttons.add(b);
}
final JFrame frame = new JFrame("App");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(buttons);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(final String[] args) {
SwingUtilities.invokeLater(MainWithBasicButtonUI::createAndShowGUI);
}
}

or, even better, MetalButtonUI like so:

import java.awt.Color;
import java.awt.GridLayout;
import java.util.Objects;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.plaf.metal.MetalButtonUI;
public class MainWithMetalButtonUI {
public static class SelectButtonUI extends MetalButtonUI {
public SelectButtonUI() {
selectColor = super.getSelectColor();
}
public void setSelectColor(final Color selectColor) {
this.selectColor = Objects.requireNonNull(selectColor);
}
@Override
protected Color getSelectColor() {
return selectColor;
}
}
private static void createAndShowGUI() {
final int rows = 3, cols = 3;
final Color[] colors = new Color[]{Color.RED.brighter(), Color.GREEN.brighter(), Color.CYAN};
final JPanel buttons = new JPanel(new GridLayout(rows, cols, 2, 2));
final Random rand = new Random();
for (int i = 0; i < rows * cols; ++i) {
final JButton b = new JButton("Button");
b.setBackground(colors[rand.nextInt(colors.length)]);
final SelectButtonUI ui = new SelectButtonUI();
ui.setSelectColor(b.getBackground().darker());
b.setUI(ui);
buttons.add(b);
}
final JFrame frame = new JFrame("App");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(buttons);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(final String[] args) {
SwingUtilities.invokeLater(MainWithMetalButtonUI::createAndShowGUI);
}
}

The only problem with this, is that all your buttons are always going to look like in the metal L&F.