Java, set colour of a button and not the border on a macOS?

Question

I'm trying to assign random colors to my buttons on mouseclick. The action itself seems to work but it is not coloring my button - but the border instead! :( (FYI, I'm just starting to learn to code so I apologize for my '2+2=4' skills)

It also won't let me do setBorderPainted(false) within the If statements or anywhere else.

Here's my code:

import javax.swing.border.Border;
import javax.xml.transform.Source;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

public class buttonTest extends JFrame implements ActionListener {

    JPanel p = new JPanel();
    Random rand = new Random();
    Button one, two, three, four, five, six, seven, eight, nine;


    public static void main(String[] args) {

        new buttonTest();
    }

    public buttonTest() {
        super("ColourButton(2.0)");
        setSize(500, 500);

        setDefaultCloseOperation(EXIT_ON_CLOSE);

        one = new Button("one");
        two = new Button("two");
        three = new Button("three");
        four = new Button("four");
        five = new Button("five");
        six = new Button("six");
        seven = new Button("seven");
        eight = new Button("eight");
        nine = new Button("nine");

        float r = rand.nextFloat();
        float g = rand.nextFloat();
        float b = rand.nextFloat();

        Color randColor = new Color(r, g, b);


        p.setLayout(new GridLayout(3, 3));
        p.add(one);
        p.add(two);
        p.add(three);
        p.add(four);
        p.add(five);
        p.add(six);
        p.add(seven);
        p.add(eight);
        p.add(nine);

        one.addActionListener(this);
        two.addActionListener(this);
        three.addActionListener(this);
        four.addActionListener(this);
        five.addActionListener(this);
        six.addActionListener(this);
        seven.addActionListener(this);
        eight.addActionListener(this);
        nine.addActionListener(this);


        add(p);
        setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        String clickedbutton = e.getActionCommand();
        System.out.println(clickedbutton + " button clicked.");


        float r = rand.nextFloat();
        float g = rand.nextFloat();
        float b = rand.nextFloat();

        Color randColor = new Color(r, g, b);


        if (e.getSource() == one) {
            one.setBackground(new Color(r,g,b));

        } else if (e.getSource() == two) {
            two.setBackground(new Color(r,g,b));

        } else if (e.getSource() == three) {
            three.setBackground(new Color(r,g,b));

        } else if (e.getSource() == four) {
            four.setBackground(new Color(r,g,b));

        } else if (e.getSource() == five) {
            five.setBackground(new Color(r,g,b));

        } else if (e.getSource() == six) {
            six.setBackground(new Color(r,g,b));

        } else if (e.getSource() == seven) {
            seven.setBackground(new Color(r,g,b));

        } else if (e.getSource() == eight) {
            eight.setBackground(new Color(r,g,b));

        } else {
            nine.setBackground(new Color(r,g,b));
        }


        }

    }

Answer 1

The "long" answer would involve creating your own UI delegate class which allowed you to take full control over the buttons appearance, but that seems like a lot of effort for something so simple.

A place to start is looking at setBorderPainted and setContentAreaFilled. This will allow you to, generally, remove all the customisation done by the platforms UI delegate, but in my testing, I also need to use setOpaque(true)

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new ButtonTest());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class ButtonTest extends JPanel implements ActionListener {

        Random rand = new Random();
        JButton buttons[];

        public ButtonTest() {
            buttons = new JButton[9];
            setLayout(new GridLayout(3, 3));
            for (int i = 0; i < buttons.length; i++) {
                buttons[i] = new JButton(Integer.toString(i));

                buttons[i].setBorderPainted(false);
                // This may not be needed, but shouldn't hurt
                buttons[i].setContentAreaFilled(false);
                // This is what fixed the issue for me
                // But you might need to consider providing a "default"
                // background color OR change this in the `actionPerformed`
                // method
                buttons[i].setOpaque(true);

                buttons[i].addActionListener(this);
                add(buttons[i]);
            }
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            if (!(e.getSource() instanceof JButton)) {
                return;
            }
            String clickedbutton = e.getActionCommand();
            System.out.println("You clicked " + clickedbutton);

            float r = rand.nextFloat();
            float g = rand.nextFloat();
            float b = rand.nextFloat();

            JButton button = (JButton) e.getSource();

            button.setBackground(new Color(r, g, b));
        }
    }
}

Answer 2

Use button.setBorderPainted(false); for all the JButtons, which should take away the border. But if that's not what you're talking about then I don't understand what you're trying to do; your JButtons are being colored when they are clicked, not the border.

Also, in order to reduce your code, I highly recommend creating a JButton array that holds all of your JButtons so you don't need to write code to initialize and set the color of every inividual JButton.

Here is the revised code that I wrote:

 import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 import java.util.Random;
 import javax.swing.*;

 public class ButtonTest extends JFrame implements ActionListener {

JPanel p = new JPanel();
Random rand = new Random();
JButton buttons[];


public static void main(String[] args) {

    new ButtonTest();
}

public ButtonTest() {
    super("ColourButton(2.0)");
    setSize(500, 500);

    setDefaultCloseOperation(EXIT_ON_CLOSE);

    buttons = new JButton[9];
    p.setLayout(new GridLayout(3, 3));
    for (int i = 0; i < buttons.length; i++)
    {
        buttons[i] = new JButton(Integer.toString(i));
        buttons[i].setBorderPainted(false);
        buttons[i].addActionListener(this);
        p.add(buttons[i]);
    }
    
    add(p);
    setVisible(true);
}

@Override
public void actionPerformed(ActionEvent e) {
    String clickedbutton = e.getActionCommand();
    System.out.println(clickedbutton + " button clicked.");

    float r = rand.nextFloat();
    float g = rand.nextFloat();
    float b = rand.nextFloat();

    JButton button = (JButton)e.getSource();

    button.setBackground(new Color(r,g,b));
    button.setForeground(new Color(0, 0, 0, 250));
}
}