In this example we are going to talk about how to work with multiple listeners in Java. This is particularly useful when you want to register more than one listeners in a single component, a button for instance.
All you have to do to work with multiple listeners is:
- Create a class that extends
JFrameand implementsActionListener. - Create an number of these
JFramesand put them in an array. This array could easily hold any class as long as it implements theActionListenerinterface. - Create a master
JFramecomponent that has aJButtonas a field. Then go through the array of theActionListenersand useJButton.addActionListenermethod to register each on of them to the button.
Let’s take a closer look at the code snippets that follow:
package com.javacodegeeks.java.core;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class MultiWinListener {
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
showUI();
}
});
}
private static void showUI() {
Two fr1 = new Two();
fr1.setVisible(true);
Two fr2 = new Two();
fr2.setVisible(true);
ActionListener[] broFrames = { fr1, fr2 };
One f1 = new One(broFrames);
f1.setVisible(true);
}
}
class One extends JFrame {
JButton button = new JButton("Press Here!");
public One(ActionListener[] frs) {
getContentPane().add(button);
for (int c = 0; c < frs.length; c++) {
button.addActionListener(frs);
}
}
}
class Two extends JFrame implements ActionListener {
protected JLabel label = new JLabel("");
public Two() {
getContentPane().add(label);
}
@Override
public void actionPerformed(ActionEvent event) {
label.setText("OK");
}
}
This was an example on how to work with Multiple Listeners in Java.
