在Windows上设置JButton背景颜色

Question

I have a JButton which I want to set the background to a color.

JButton button = new JButton();
button.setVisible(true);
button.setPreferredSize(new Dimension(student_scroll.getWidth(), 50));
button.setBorder(BorderFactory.createLineBorder(Color.WHITE, 1));
button.setBackground(Color.BLACK);
button.setForeground(Color.WHITE);
button.setOpaque(true);

I used this for mac and it showed up as I wanted it to be. However, upon trying it on windows, the foreground is white(as it should) but the background is empty.

Setting background color to JButton

says to add button.setContentAreaFilled(false); which I did but had no effect. Most others say to add button.setOpaque(true); which I also did already.

What else do I have to do so that it will show up with a black background?

EDIT

As requested, the SSCCE:

import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class MainSwing extends JFrame {
    private static final long serialVersionUID = -8231889836024827530L;

    public static void main(String[] args) {
        try {
            System.setProperty("apple.laf.useScreenMenuBar", "true");
            System.setProperty("com.apple.mrj.application.apple.menu.about.name", "Test");
            UIManager.put("ScrollBarUI", "main.CustomScrollBarUI");
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    }
    catch(ClassNotFoundException e) {
            System.out.println("ClassNotFoundException: " + e.getMessage());
    }
    catch(InstantiationException e) {
            System.out.println("InstantiationException: " + e.getMessage());
    }
    catch(IllegalAccessException e) {
            System.out.println("IllegalAccessException: " + e.getMessage());
    }
    catch(UnsupportedLookAndFeelException e) {
            System.out.println("UnsupportedLookAndFeelException: " + e.getMessage());
    }
        SwingUtilities.invokeLater( new Runnable() {
            public void run() {
                JFrame frame = new JFrame() {

                    Container c = getContentPane();
                    JButton button = new JButton("Hello");
                    {
                        button.setText("Hello");
                        button.setVisible(true);
                        button.setPreferredSize(new Dimension(100, 50));
                        button.setBorder(BorderFactory.createLineBorder(Color.WHITE, 1));
                        button.setBackground(Color.BLACK);
                        button.setForeground(Color.WHITE);
                        button.setOpaque(true);
                        c.add(button);
                    }

                };
                frame.setSize(500, 500);
                frame.setBackground(Color.BLACK);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

It seems that the problem has something to do with the line: UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); as when I remove it, the buttons are black.

Answer 1

I'm guessing from those UIManager key/value pairs that the PLAF is the OS X based Aqua PLAF. And that seems to be part of the problem here. Here it is without the content area filled on Windows.

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

public class MainSwing extends JFrame {

    public static void main(String[] args) {
        try {
            System.setProperty("apple.laf.useScreenMenuBar", "true");
            System.setProperty("com.apple.mrj.application.apple.menu.about.name", "Test");
            UIManager.put("ScrollBarUI", "main.CustomScrollBarUI");
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Exception e) {
            e.printStackTrace(); // more info for less LOC!
        }
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JFrame frame = new JFrame() {

                    Container c = getContentPane();
                    JButton button = new JButton("Hello");

                    {
                        c.setLayout(new GridLayout(0,1));
                        c.add(new JButton("Hi"));
                        button.setText(UIManager.getSystemLookAndFeelClassName());
                        button.setVisible(true);
                        button.setPreferredSize(new Dimension(400, 100));
                        button.setBorder(BorderFactory.createLineBorder(Color.WHITE, 1));
                        button.setContentAreaFilled(false);
                        button.setBackground(Color.BLACK);
                        button.setForeground(Color.WHITE);
                        button.setOpaque(true);
                        c.add(button);
                    }
                };
                frame.pack();
                frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

Answer 2

It seems that the problem has something to do with the line: UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); as when I remove it, the buttons are black.

So that is extra information we didn't have before you created the SSCCE (which is why you should always post a SSCCE with your question).

It also tells you the problem is not with your code but with the LAF. The Windows LAF ignores the setBackground(...) method and paints its own background.

One option would be to add an Icon to the button of your desired color. Then you can configure the text to be painted in the center of the button:

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

public class ColorIcon implements Icon
{
    private Color color;
    private int width;
    private int height;

    public ColorIcon(Color color, int width, int height)
    {
        this.color = color;
        this.width = width;
        this.height = height;
    }

    public int getIconWidth()
    {
        return width;
    }

    public int getIconHeight()
    {
        return height;
    }

    public void paintIcon(Component c, Graphics g, int x, int y)
    {
        g.setColor(color);
        g.fillRect(x, y, width, height);
    }

    public static void main(String[] args)
    {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }

    public static void createAndShowGUI()
    {
        JPanel panel = new JPanel( new GridLayout(2, 2) );

        for (int i = 0; i < 4; i++)
        {
            Icon icon = new ColorIcon(Color.RED, 50, 50);
            JButton label = new JButton( icon );
            label.setText("" + i);
            label.setHorizontalTextPosition(JButton.CENTER);
            label.setVerticalTextPosition(JButton.CENTER);
            panel.add(label);
        }

        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(panel);
        f.setSize(200, 200);
        f.setLocationRelativeTo( null );
        f.setVisible(true);
    }
}

Then is should work on all LAF's.