Re: Communicating from event handler to container

From:
"Michael Dunn" <m_odunn@yahoo.com>
Newsgroups:
comp.lang.java.help
Date:
25 Feb 2007 20:27:41 -0800
Message-ID:
<1172464061.584984.63560@j27g2000cwj.googlegroups.com>
On Feb 26, 1:32 pm, "eastside" <easts...@spamarrest.com> wrote:

I have a class, let's call it AC, which extends JPanel. Each instance of AC
also contains a JTextField. The actionlistener for the text field is also in
the class definition of AC. If a certain condition is detected by the
actionlistener, the object needs to tell the parent object that contains AC
to inform all other instances of AC that they need to be updated. How is
this communication back to the parent object usually accomplished in Java?
Thanks!


maybe(??) this might do what you want

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Testing
{
  public void buildGUI()
  {
    JPanel p = new JPanel(new GridLayout(5,1));
    for(int x = 0; x < 5; x++) p.add(new AC());
    JFrame f = new JFrame();
    f.getContentPane().add(p);
    f.pack();
    f.setLocationRelativeTo(null);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setVisible(true);
  }
  public static void main(String[] args)
  {
    SwingUtilities.invokeLater(new Runnable(){
      public void run(){
        new Testing().buildGUI();
      }
    });
  }
}
class AC extends JPanel
{
  static java.util.List acPanels = new java.util.ArrayList();
  JTextField tf = new JTextField(5);
  public AC()
  {
    acPanels.add(this);
    add(tf);
    tf.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent ae){
        for(int x = 0, y = acPanels.size(); x < y; x++)
        {
          AC acPanel = (AC)acPanels.get(x);
          acPanel.tf.setText(acPanel.tf.getText()+x);
        }
      }
    });
  }
}

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