Implementation problem

Question

Hi
I wrote a frame class:
public class MyFrame extends javax.swing.JFrame{
    private MyPanel buttonPanel;
    private initGUI(){
            buttonPanel = new MyPanel();
            getContentPane().add( buttonPanel, new GridBagConstraints( 1, 4, 5, 1, 0.0, 0.0, GridBagConstraings.CENTER, GridBagConstraints.BOTH, new Insets( 0, 0, 0, 0), 0, 0));
    private changeSomething(){
        // just do anything
}and this panel class containing a button:
public class MyPanel extends javax.swing.JPanel{
    private JButton buttonDoSomething;
    private initPanel(){
        try{
            GridBagLayout layout = new GridBagLayout();
            button = new JButton();
            button.addActionListener( new ActionListener(){
                public void actionPerformed( ActionEvent ae){
                    if( ael.getSource().equals( button)){
                        // how can I fix this, that the method in the frame class will be called?
            this.add( button, new GridBagConstraints( 1, 0, 1, 1, 0.0, 0.0, GridBagCostraints.CENTER, GridBagConstraints.BOTH, new Insets( 0, 3, 0, 0), 0, 0));
            button.setText( "do something");
}I now like that a click on the button executes the MyFrame's method changeSomething(). What is an elegant way to get that implemented?

Answer 1

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
class Testing extends JFrame
  JLabel label = new JLabel("Hello World",JLabel.CENTER);
  public Testing()
    setLocation(400,300);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    getContentPane().add(label,BorderLayout.NORTH);
    getContentPane().add(new MyPanel(this),BorderLayout.CENTER);
    pack();
  public void changeSomething(String text)
    label.setText(text);
  public static void main(String[] args){new Testing().setVisible(true);}
class MyPanel extends JPanel
  private JButton buttonDoSomething;
  public MyPanel(Testing app)
    initPanel(app);
  private void initPanel(final Testing mainApp)
    GridBagLayout layout = new GridBagLayout();
    buttonDoSomething = new JButton( "do something");
    buttonDoSomething.addActionListener( new ActionListener(){
        public void actionPerformed( ActionEvent ae){
            //if( ael.getSource().equals( button)){//not needed - added directly to source
          mainApp.changeSomething("Goodbye");}});
    this.add(buttonDoSomething, new GridBagConstraints());
}