addMouseListener for a JPanel

Question

Today I have a problem.. My program make a 8x8 grid and show the coord when I click on a JButton.

BUT I refuse to use JButton and I need to go for JPanel.. But my addMouseListener isn't working so I don't know how is it possible to fix that I'm searching since 4h.....

    package coordboutons;

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

    public class CoordBoutons extends JFrame {

        CoordBoutons() {
            super("GridLayout");
            setDefaultCloseOperation(EXIT_ON_CLOSE);
            Container contenant = getContentPane();
            contenant.setLayout(new GridLayout(8, 8));

            for (int i = 0; i < 8; i++) 
                for (int j = 0; j < 8; j++)
                    contenant.add(new CaseEchiquier(i, j));

            pack();
            setVisible(true);
        }

        **class CaseEchiquier extends JPanel** {
            private int lin, col;
            CaseEchiquier(int i, int j) {
                lin = i;
                col = j;
                setPreferredSize(new Dimension(80, 75));
                setBackground((i + j) % 2 == 0 ? Color.WHITE : Color.GRAY);
                addActionListener(new ActionListener() {
                    public void actionPerformed(ActionEvent evt) {
                        System.out.println((char)('a' + col) + "" + (8 - lin));

                    }
                });
            }


        }

        public static void main(String[] args) {
            JFrame.setDefaultLookAndFeelDecorated(true);
            CoordBoutons coordBoutons = new CoordBoutons();
        }
    }

Glasshouse

I might be missing something here but ActionListener isn't a MouseListener – Marx

You mean addActionListener isnt working. That would be because you can't register JPanel with this type of listener – Rodmann

yours trying to add a mouselistener to your panels right? but your code sais actionListener, there is no actionlistener method in JPanel. and i think its a bad idea to have 64 newMouseListeners, you only need one for all 64 panels. so add a mouselistener as a parameter in your CaseEchiquier(int i, int j, MouseListener m) – Dreadful

"I refuse to use JButton" ... why? – Hoop

Answer 1

JPanel doesn't have ActionListener capabilities. Instead, you need to use a MouseListener

import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class CoordBoutons extends JFrame {

    CoordBoutons() {
        super("GridLayout");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        Container contenant = getContentPane();
        contenant.setLayout(new GridLayout(8, 8));

        for (int i = 0; i < 8; i++) {
            for (int j = 0; j < 8; j++) {
                contenant.add(new CaseEchiquier(i, j));
            }
        }

        pack();
        setVisible(true);
    }

    class CaseEchiquier extends JPanel {

        private int lin, col;

        CaseEchiquier(int i, int j) {
            lin = i;
            col = j;
            setPreferredSize(new Dimension(80, 75));
            setBackground((i + j) % 2 == 0 ? Color.WHITE : Color.GRAY);
            addMouseListener(new MouseAdapter() {
                private Color background;

                @Override
                public void mousePressed(MouseEvent e) {
                    background = getBackground();
                    setBackground(Color.RED);
                    repaint();
                }

                @Override
                public void mouseReleased(MouseEvent e) {
                    setBackground(background);
                }
            });
//            addActionListener(new ActionListener() {
//                public void actionPerformed(ActionEvent evt) {
//                    System.out.println((char) ('a' + col) + "" + (8 - lin));
//
//                }
//            });
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame.setDefaultLookAndFeelDecorated(true);
                CoordBoutons coordBoutons = new CoordBoutons();
            }
        });
    }
}

Take a look at How to Write Mouse Listeners for more details...

Marx

Oh men thank you so much I searched since long hours... And now I understood it works and I can get coords by clicking on a case =) – Glasshouse

Thank you for your help! Very useful ;) However, how can I get coordinates from each case without using "System.out.println". I want something like getX() and getY() with letters A-H (column) and numbers 1-8 (rows) – Glasshouse

This will depend on more information then you actually have, you would need to know the width of each column and height of each row. A better solution might be to using the information from the class itself, the lin and col – Marx

Answer 2

The problem is that the method addActionListener does not exists for a JPanel. You should use the appropriate listener for this case (java.awt.event.MouseListener). Since MouseListener is an interface (and you don't want to implement all of its methods), you could use a MouseAdapter and override only the method(s) you need, like this:

addMouseListener(new MouseAdapter() {
    @Override
    public void mouseClicked(MouseEvent e) {
        System.out.println((char)('a' + col) + "" + (8 - lin));
    }
});

Endres

Thank you so much I understood now =) Great help ! – Glasshouse