How to exchange the Joptionpane background with an image?

Question

You can use that "ImageIcon" as background of a JOptionPane?

Follow the code I tried:

public static void main(String args []){

  UIManager UI = new UIManager();
  ImageIcon icon = new ImageIcon("Imagens/Imagem.jpg"); //Declara Icon como Imagem

  UI.put("OptionPane.messageFont", new Font("Times New Roman", Font.PLAIN, 18));
  UI.put("OptionPane.messageForeground", Color.white);
  UI.put("OptionPane.background", Color.black);  
  UI.put("Panel.background", Color.black);

Answer 1

I don’t think it’s possible. JOptionPane is already a basic implementation of a modal warning window. If you want something more customized, the best way is to build your own component.

Change by settings of look and Feel(LAF) is much more complex as it only changes when the LAF Nimbus is applied, if you switch to another LAF, all these changes will be ignored. As an alternative to this, I built this JDialog, that functions as a JOptionpane but customizable, relevant excerpts are commented:

class JOptionBackgroundPane extends JDialog {

    BufferedImage imgBackground;
    JLabel label;

    public JOptionBackgroundPane(BufferedImage imgBackgound, String message) {
        this.imgBackground = imgBackgound;
        makeUI(message);
    }

    private void makeUI(String message) {

        JPanel backgroundPane = new JPanel() {

            @Override
            public void paintComponent(Graphics g) {

                super.paintComponents(g);
                //desenha a imagem no componente como fundo
                g.drawImage(imgBackground, 0, 0, this);
            }
        };

        label = new JLabel(message);

        //mude para cor de primeiro plano que quiser
        label.setForeground(Color.BLACK);
        //mude para o formato de fonte que quiser
        label.setFont(new Font("Times New Roman", Font.PLAIN, 18));

        label.setAlignmentX(Component.CENTER_ALIGNMENT);

        JButton btn = new JButton("OK");

        btn.setAlignmentX(Component.CENTER_ALIGNMENT);

        btn.addActionListener(e -> {
            dispose();
        });

        backgroundPane.setLayout(new BoxLayout(backgroundPane, BoxLayout.Y_AXIS));
        //workaround para evitar que o label fique colado no topo
        backgroundPane.add(Box.createRigidArea(new Dimension(0, Math.round(getPreferredSize().height*0.1f))));
        backgroundPane.add(label);
        backgroundPane.add(Box.createVerticalGlue());
        backgroundPane.add(btn);
        //workaround para evitar que o label fique colado na parte de baixo
        backgroundPane.add(Box.createRigidArea(new Dimension(0, Math.round(getPreferredSize().height*0.1f))));

        setModal(true);
        setResizable(false);
        setContentPane(backgroundPane);
        pack();
        setLocationRelativeTo(null);
    }

    @Override
    public Dimension getPreferredSize() {
        //força o container a ter sempre o mesmo tamanho da imagem
        return new Dimension(imgBackground.getWidth(), imgBackground.getHeight());
    }
}

to use, just pass an image through a BufferredImage, sort of like this:

BufferedImage image = ImageIO.read(SuaClasse.class.getResource("path da imagem"));

JOptionBackgroundPane pane = new JOptionBackgroundPane(image, "mensagem");
pane.setVisible(true);

---

You can see working through the example below:

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.net.URL;

import javax.imageio.ImageIO;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class JOptionPaneBackground {
    public static void main(String[] args) throws Exception {

        BufferedImage image = ImageIO.read(
                new URL("https://www.walldevil.com/wallpapers/a64/thumb/background-wallpapers-blue-opera-light-images.jpg"));

        JOptionBackgroundPane pane = new JOptionBackgroundPane(image, "Teste");
        pane.setVisible(true);

    }
}

class JOptionBackgroundPane extends JDialog {

    BufferedImage imgBackground;
    JLabel label;

    public JOptionBackgroundPane(BufferedImage imgBackgound, String message) {
        this.imgBackground = imgBackgound;
        makeUI(message);
    }

    private void makeUI(String message) {

        JPanel backgroundPane = new JPanel() {

            @Override
            public void paintComponent(Graphics g) {

                super.paintComponents(g);
                //desenha a imagem no componente como fundo
                g.drawImage(imgBackground, 0, 0, this);
            }
        };

        label = new JLabel(message);

        //mude para cor de primeiro plano que quiser
        label.setForeground(Color.BLACK);
        //mude para o formato de fonte que quiser
        label.setFont(new Font("Times New Roman", Font.PLAIN, 18));

        label.setAlignmentX(Component.CENTER_ALIGNMENT);

        JButton btn = new JButton("OK");

        btn.setAlignmentX(Component.CENTER_ALIGNMENT);

        btn.addActionListener(e -> {
            dispose();
        });

        backgroundPane.setLayout(new BoxLayout(backgroundPane, BoxLayout.Y_AXIS));
        //workaround para evitar que o label fique colado no topo
        backgroundPane.add(Box.createRigidArea(new Dimension(0, Math.round(getPreferredSize().height*0.1f))));
        backgroundPane.add(label);
        backgroundPane.add(Box.createVerticalGlue());
        backgroundPane.add(btn);
        //workaround para evitar que o label fique colado na parte de baixo
        backgroundPane.add(Box.createRigidArea(new Dimension(0, Math.round(getPreferredSize().height*0.1f))));

        setModal(true);
        setResizable(false);
        setContentPane(backgroundPane);
        pack();
        setLocationRelativeTo(null);
    }

    @Override
    public Dimension getPreferredSize() {
        //força o container a ter sempre o mesmo tamanho da imagem
        return new Dimension(imgBackground.getWidth(), imgBackground.getHeight());
    }
}