How to call a private method in a JFrame

Question

I have a Frame which has some properties like its size, bgcolor plus other parameters, as instance variables. There is a button on the Frame with the caption : "set properties". When one clicks on that button, a new frame should appear via which a user can change the values of the parameters of the main Frame (i.e size, bgcolor,..etc). The user would input the new values in the textfields or radio buttons that are on the new frame, and then click a submit button, which has to exist on the same NFrame. How can I do that so that when the submit button is pressed, the parameters values are updated and so is the display view ?
I made it this way : I created 2 classes, the main frame and the new Frame. I made the new Frame an instance variable of the main Frame. When the user clicks the " set properties" button on the main Frame, the new Frame is shown. The user enters new values for some of the parameters and clicks submit. The parameters in the new Frame are updated. UP TO HERE EVERYTHING WENT JUST FINE. Now, there is a private method in the main frame that changes the color, size, ...etc of the main frame according to the values stored in the instance variables color, size,...etc. THE QUESTION IS: How can the new Frame display the changes after the values have been updated ? That is, how can it call the "private" method in the main class?? Should the new class be a child class of the main class to be able to access it's private methods ??

Answer 1

import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class CallingHome
    SkinMod skinMod;
    JPanel panel;
    public CallingHome()
        // send reference so SkinMod can call methods in this class
        skinMod = new SkinMod(this);
        JButton change = new JButton("change properties");
        change.addActionListener(new ActionListener()
            public void actionPerformed(ActionEvent e)
                skinMod.showDialog();
        JPanel north = new JPanel();
        north.add(change);
        panel = new JPanel();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(north, "North");
        f.getContentPane().add(panel);
        f.setSize(300,100);
        f.setLocation(200,200);
        f.setVisible(true);
    public void setBackground(Color color)
        panel.setBackground(color);
        panel.repaint();
    public static void main(String[] args)
        new CallingHome();
class SkinMod
    CallingHome callHome;
    Random seed;
    JDialog dialog;
    public SkinMod(CallingHome ch)
        callHome = ch;
        seed = new Random();
        createDialog();
    public void showDialog()
        if(!dialog.isShowing())
            dialog.setVisible(true);
    private void createDialog()
        JButton change = new JButton("change background");
        change.addActionListener(new ActionListener()
            public void actionPerformed(ActionEvent e)
                callHome.setBackground(getColor());
                dialog.dispose();
        JPanel p = new JPanel();
        p.add(change);
        dialog = new JDialog();
        dialog.getContentPane().add(p);
        dialog.setSize(200,100);
        dialog.setLocation(525,200);
    private Color getColor()
        return new Color(seed.nextInt(0xffffff));
}