MouseListener-repaint（）不起作用

Question

I'm trying to make a little board game in Java, the following is a little excerpt of it, just to show what my problem is.

I've got a JPanel with an array of JLabels to visualize a board. Every Label has its own MouseListener. In the beginning, all Labels are red, if I click any of them, a I'd like all of them to turn green.

I know it can be easily done using setBackground for every Label, but I'd like that to be done at the level of Panel, because it will be probably connected with simple board of ex chars, on which the whole game would develop, and Labels would be just visualizing that.

I have no idea, what I'm doing wrong. I guess I haven't thought it well, but I don't know how to do that. Could anyone please help me?

Please don't suggest the paintComponent overriden, it's just effect of my desperation and it doesn't work of course.

Main class:

import java.awt.EventQueue;

public class Main {
    public static void main( String args[] ) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Window();

            }
        });
    }
}

Window class:

import java.awt.FlowLayout;
import java.awt.Dimension;
import javax.swing.JFrame;

public class Window extends JFrame {

    public Window() {
        setMinimumSize( new Dimension(500, 600) );
        setLocationRelativeTo( null );
        setDefaultCloseOperation( EXIT_ON_CLOSE );
        setLayout( new FlowLayout() );

        PanelBoard b = new PanelBoard();
        add( b );
        setVisible( true );
    }
}

Panel class:

import javax.swing.JPanel;
import java.awt.FlowLayout;
import java.awt.Dimension;
import java.awt.Color;

public class PanelBoard extends JPanel {

    private Field fields[][] = new Field[6][6];

    public PanelBoard() {
        setLayout( new FlowLayout( FlowLayout.CENTER, 0, 0) );
        setPreferredSize( new Dimension( 60*6, 60*6 ) );

        addFields( Color.red );

    }

    public void addFields( Color c ) {
        for( int i=0; i<6; i++)
            for( int j=0; j<6; j++ ) {
                fields[i][j] = new Field( this, c );
                add( fields[i][j] );
            }
    }
}

Field class:

import javax.swing.BorderFactory;
import javax.swing.JLabel;
import java.awt.Color;
import java.awt.Dimension;

public class Field extends JLabel {

    public Field( PanelBoard pb, Color c) {
        setBackground( c );
        setBorder( BorderFactory.createLineBorder( Color.black ) );
        setOpaque( true );
        setPreferredSize( new Dimension( 60, 60 ) );

        addMouseListener( new Mouse( pb, this ) );
    }
}

MouseListener class:

import java.awt.Color;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.BorderFactory;

public class Mouse implements MouseListener {

    PanelBoard pb;
    Field f;

    public Mouse( PanelBoard pb, Field f ) {
        this.pb = pb;
        this.f = f;
    }

    @Override
    public void mouseReleased( MouseEvent arg ) {
        pb.addFields( Color.green );
        pb.revalidate();
        pb.repaint();

    }

    @Override
    public void mouseClicked( MouseEvent arg ) {}
    @Override
    public void mousePressed( MouseEvent arg ) {}
    @Override
    public void mouseExited( MouseEvent arg ) {}
    @Override
    public void mouseEntered( MouseEvent arg ) {}
}

Answer 1

Just add this method to PanelBoard :

public void modifyFields( Color c ) {
    for( int i=0; i<6; i++)
        for( int j=0; j<6; j++ ) {
          fields[i][j].setBackground(c);
        }
}

and modify mouseReleased method of class Mouse like this:

public void mouseReleased( MouseEvent arg ) {
    pb.modifyFields( Color.green );
}