Easy question: Give access to a class in another class.

Question

Stupid title, but dont know how to express myself :P Sorry for that.
To the problem. Never had this problem before, and I know its a really easy solution to this.
I have my Main class, which creates a MyView class. Inside this class, I make to new classes(or instances of classes i've already made), MyPanel and MyToolsPanel. Now I want to add buttons inside the MyToolsPanel class, and add actionlisteners to these buttons inside MyPanel.
What I'v always done to grant access to MyToolsPanel inside of MyTools, is to simply add a
//this is the MyPanel class
MyToolsPanel mtp;
public void setMtp(MyToolsPanel mtp){
this.mtp = mtp;
}and then in the MyView class which create these to classes, I put a command: mp.setMtp(mtp);
When I run this it doesnt work.. Why? Should be easy to solve, since it obviously is a stupid problem that I just dont see. :P Feeling kind of stupid to ask this question, but this is how it is...
EDIT: I might have to implement actionListener inside the MyToolsPanel class?
Edited by: Stianbl on Sep 28, 2008 4:59 PM

Answer 1

one way:
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JTextField;
* Subclasses JPanel, can send text out via the getText() method
* can hook into button press via addActionListener
* @author Pete
public class PanelCommSender extends JPanel
  private JTextField sendingField = new JTextField(12);
  private JButton sendButton = new JButton("Send");
  public PanelCommSender()
    add(sendingField);
    add(sendButton);
  public void addActionListener(ActionListener al)
    // attach this listener to the button
    sendButton.addActionListener(al);
   * call this to get the text currently in the textfield
   * @return String text
  public String getText()
    return sendingField.getText();
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
* Subclasses JPanel, receives text from another class
* @author Pete
public class PanelCommReceiver extends JPanel
  private JTextField showResultsField = new JTextField(12);
  public PanelCommReceiver()
    showResultsField.setEditable(false);
    add(new JLabel("Results from other panel: "));
    add(showResultsField);
   * call this to set text of textField
   * @param text
  public void setText(String text)
    showResultsField.setText(text);
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JDialog;
import javax.swing.JFrame;
public class PanelCommControl
  private static void createAndShowUI()
    // create new instances of the receiving and sending panels:
    final PanelCommReceiver receivePanel = new PanelCommReceiver();
    final PanelCommSender sendPanel = new PanelCommSender();
    // let the communicate w/ each other
    sendPanel.addActionListener(new ActionListener()
      public void actionPerformed(ActionEvent e)
        receivePanel.setText(sendPanel.getText());
    // place the receiving JPanel into a JFrame
    JFrame frame = new JFrame("Receiving Panel");
    frame.getContentPane().add(receivePanel);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setPreferredSize(new Dimension(300, 300)); // make it bigger so it can be seen
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
    // place the sending JPanel into a JDialog
    JDialog dialog = new JDialog(frame, "Sending Panel", false);
    dialog.getContentPane().add(sendPanel);
    dialog.pack();
    dialog.setLocationRelativeTo(null);
    dialog.setVisible(true);
  public static void main(String[] args)
    java.awt.EventQueue.invokeLater(new Runnable()
      public void run()
        // run the whole show in a thread-safe manner
        createAndShowUI();
}