import javax.swing.*;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;
import java.awt.Insets;
import java.awt.Dimension;
import java.awt.Color;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class MultiListener extends JPanel
implements ActionListener {
JTextArea topTextArea;
JTextArea bottomTextArea;
JButton button1, button2;
final static String newline = "\n";
public MultiListener() {
super(new GridBagLayout());
GridBagLayout gridbag = (GridBagLayout)getLayout();
GridBagConstraints c = new GridBagConstraints();
JLabel l = null;
c.fill = GridBagConstraints.BOTH;
c.gridwidth = GridBagConstraints.REMAINDER;
l = new JLabel("What MultiListener hears:");
gridbag.setConstraints(l, c);
add(l);
c.weighty = 1.0;
topTextArea = new JTextArea();
topTextArea.setEditable(false);
JScrollPane topScrollPane = new JScrollPane(topTextArea);
Dimension preferredSize = new Dimension(200, 75);
topScrollPane.setPreferredSize(preferredSize);
gridbag.setConstraints(topScrollPane, c);
add(topScrollPane);
c.weightx = 0.0;
c.weighty = 0.0;
l = new JLabel("What Eavesdropper hears:");
gridbag.setConstraints(l, c);
add(l);
c.weighty = 1.0;
bottomTextArea = new JTextArea();
bottomTextArea.setEditable(false);
JScrollPane bottomScrollPane = new JScrollPane(bottomTextArea);
bottomScrollPane.setPreferredSize(preferredSize);
gridbag.setConstraints(bottomScrollPane, c);
add(bottomScrollPane);
c.weightx = 1.0;
c.weighty = 0.0;
c.gridwidth = 1;
c.insets = new Insets(10, 10, 0, 10);
button1 = new JButton("Blah blah blah");
gridbag.setConstraints(button1, c);
add(button1);
c.gridwidth = GridBagConstraints.REMAINDER;
button2 = new JButton("You don't say!");
gridbag.setConstraints(button2, c);
add(button2);
button1.addActionListener(this);
button2.addActionListener(this);
button2.addActionListener(new Eavesdropper(bottomTextArea));
setPreferredSize(new Dimension(450, 450));
setBorder(BorderFactory.createCompoundBorder(
BorderFactory.createMatteBorder(
1,1,2,2,Color.black),
BorderFactory.createEmptyBorder(5,5,5,5)));
}
public void actionPerformed(ActionEvent e) {
topTextArea.append(e.getActionCommand() + newline);
topTextArea.setCaretPosition(topTextArea.getDocument().getLength());
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("MultiListener");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
JComponent newContentPane = new MultiListener();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
class Eavesdropper implements ActionListener {
JTextArea myTextArea;
public Eavesdropper(JTextArea ta) {
myTextArea = ta;
}
public void actionPerformed(ActionEvent e) {
myTextArea.append(e.getActionCommand()
+ MultiListener.newline);
myTextArea.setCaretPosition(myTextArea.getDocument().getLength());
}
}
