In this example we are going to see how to use the ChangeListener interface in Java. This is very useful when you want to monitor generic changes in your application.
In short, to use a simple ChangeListener one should follow these steps:
- Create a new
ChangeListenerinstance. - Override the
stateChangedmethod to customize the handling of specific events. - Use specific functions of components to get better undemanding of the event that occurred.
Let’s see the code:
package com.javacodegeeks.snippets.desktop;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.AbstractButton;
import javax.swing.ButtonModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class StateListener {
public static void main(String args[]) {
JFrame jFrame = new JFrame("");
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton button = new JButton("Press Me");
ActionListener actionListner = new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
AbstractButton absButton = (AbstractButton) event.getSource();
boolean selected = absButton.getModel().isSelected();
System.out.println("Selected=" + selected + "n");
}
};
ChangeListener changeListner = new ChangeListener() {
@Override
public void stateChanged(ChangeEvent event) {
AbstractButton aButton = (AbstractButton) event.getSource();
ButtonModel aModel = aButton.getModel();
boolean armed = aModel.isArmed();
boolean pressed = aModel.isPressed();
boolean selected = aModel.isSelected();
System.out.println("Armed :" + armed + " - Pressed :" + pressed + " - Selected :" + selected);
}
};
button.addActionListener(actionListner);
button.addChangeListener(changeListner);
Container cPane = jFrame.getContentPane();
cPane.add(button, BorderLayout.CENTER);
jFrame.setSize(800, 500);
jFrame.setVisible(true);
}
}
This was an example on how to use ChangeListener in Java.
so confusing even after your explanations =\