SWING - WindowListener Interface


Advertisements


The class which processes the WindowEvent should implement this interface. The object of that class must be registered with a component. The object can be registered using the addWindowListener() method.

Interface Declaration

Following is the declaration for java.awt.event.WindowListener interface −

public interface WindowListener
   extends EventListener

Interface Methods

Sr.No. Method & Description
1

void windowActivated(WindowEvent e)

Invoked when the Window is set to be the active Window.

2

void windowClosed(WindowEvent e)

Invoked when a window has been closed as a result of calling dispose on the Window.

3

void windowClosing(WindowEvent e)

Invoked when the user attempts to close the Window from the Window's system menu.

4

void windowDeactivated(WindowEvent e)

Invoked when a Window is no longer the active Window.

5

void windowDeiconified(WindowEvent e)

Invoked when a Window is changed from a minimized to a normal state.

6

void windowIconified(WindowEvent e)

Invoked when a Window is changed from a normal to a minimized state.

7

void windowOpened(WindowEvent e)

Invoked the first time a Window is made visible.

Methods Inherited

This interface inherits methods from the following interfaces −

java.awt.EventListener

WindowListener Example

Create the following Java program using any editor of your choice in say D:/ > SWING > com > tutorialspoint > gui >

SwingListenerDemo.java

package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class SwingListenerDemo {
   private JFrame mainFrame;
   private JLabel headerLabel;
   private JLabel statusLabel;
   private JPanel controlPanel;

   public SwingListenerDemo(){
      prepareGUI();
   }
   public static void main(String[] args){
      SwingListenerDemo  swingListenerDemo = new SwingListenerDemo();  
      swingListenerDemo.showWindowListenerDemo();
   }
   private void prepareGUI(){
      mainFrame = new JFrame("Java SWING Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));

      headerLabel = new JLabel("",JLabel.CENTER );
      statusLabel = new JLabel("",JLabel.CENTER);        
      statusLabel.setSize(350,100);
      
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      controlPanel = new JPanel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }
   private void showWindowListenerDemo(){
      headerLabel.setText("Listener in action: WindowListener");      
      JButton okButton = new JButton("OK");

      aboutFrame = new JFrame();
      aboutFrame.setSize(300,200);;
      aboutFrame.setTitle("WindowListener Demo");
      aboutFrame.addWindowListener(new CustomWindowListener());
      
      JPanel panel = new JPanel();      
      panel.setBackground(Color.white);            
      JLabel msglabel = new JLabel("Welcome to TutorialsPoint SWING Tutorial."
         ,JLabel.CENTER);        
      panel.add(msglabel);
      aboutFrame.add(panel);
      aboutFrame.setVisible(true); 
   }
   class CustomWindowListener implements WindowListener {
      public void windowOpened(WindowEvent e) {
      }
      public void windowClosing(WindowEvent e) {
         aboutFrame.dispose();
      }
      public void windowClosed(WindowEvent e) {
      }
      public void windowIconified(WindowEvent e) {
      }
      public void windowDeiconified(WindowEvent e) {
      }
      public void windowActivated(WindowEvent e) {
      }
      public void windowDeactivated(WindowEvent e) {
      }
   }   
}

Compile the program using the command prompt. Go to D:/ > SWING and type the following command.

D:\SWING>javac com\tutorialspoint\gui\SwingListenerDemo.java

If no error occurs, it means the compilation is successful. Run the program using the following command.

D:\SWING>java com.tutorialspoint.gui.SwingListenerDemo

Verify the following output.

SWING WindowListener
swing_event_listeners.htm

Advertisements