event

A simple ChangeListener example

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 ChangeListener instance.
  • Override the stateChanged method 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.

Byron Kiourtzoglou

Byron is a master software engineer working in the IT and Telecom domains. He is an applications developer in a wide variety of applications/services. He is currently acting as the team leader and technical architect for a proprietary service creation and integration platform for both the IT and Telecom industries in addition to a in-house big data real-time analytics solution. He is always fascinated by SOA, middleware services and mobile development. Byron is co-founder and Executive Editor at Java Code Geeks.
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Burak6
Burak6
2 years ago

so confusing even after your explanations =\

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