Question

I’m super confused with what exactly models are supposed to do in java swing. At present I’m basically trying to create a model for JButton to detect if it isPressed(); My essential goal of the model is to do something like this:

if(myButton.isPressed() ) {
    myButton.setBackground(Color.RED);
}
else{//when any other button is pressed?
    myButton.setBackground(Color.WHITE);
}

At present my code is something like this:

    numberButton = new JButton("Num");
    numberButton.setBounds(20,40,80,30);
    numberButton.addChangeListener(new ChangeListener() {
        public void stateChanged (ChangeEvent e){
           if (model.isPressed() ){
              doColorChange(model);
           }
        }
    });

I understand that this is totally wrong, but I have no idea where, and I haven’t found a tutorial that really explains what I’m doing wrong or why I need a model for this at all.

Please help me restore my sanity! Thanks a lot!

Answer 1

Use radio buttons in a button group.

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

import java.net.URL;
import javax.imageio.ImageIO;

class RedAndWhite {

    public static Image getColoredImage(Color color, int size) {
        BufferedImage bi = new BufferedImage(
            size,
            size,
            BufferedImage.TYPE_INT_RGB);
        Graphics g = bi.getGraphics();
        g.setColor(color);
        g.fillRect(0,0,size,size);

        g.dispose();
        return bi;
    }

    public static void main(String[] args) throws Exception {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                Image red = getColoredImage(Color.RED, 32);
                Image white = getColoredImage(Color.WHITE, 32);
                JPanel p = new JPanel(new GridLayout(1,0,5,5));

                ButtonGroup bg = new ButtonGroup();
                for (int ii=0; ii<6; ii++) {
                    JRadioButton b = new JRadioButton();
                    b.setSelectedIcon(new ImageIcon(red));
                    b.setIcon(new ImageIcon(white));
                    b.setContentAreaFilled(true);
                    bg.add(b);
                    p.add(b);
                }

                JOptionPane.showMessageDialog(null, p);
            }
        });
    }
}