AWT FocusAdapter Class

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Introduction

The class FocusAdapter is an abstract (adapter) class for receiving keyboard focus events. All methods of this class are empty. This class is convenience class for creating listener objects.

Class declaration

Following is the declaration for java.awt.event.FocusAdapter class:

public abstract class FocusAdapter
   extends Object
      implements FocusListener

Class constructors

S.N.Constructor & Description
1FocusAdapter()

Class methods

S.N.Method & Description
1void focusGained(FocusEvent e)
Invoked when a component gains the keyboard focus.
2focusLost(FocusEvent e)
Invoked when a component loses the keyboard focus.

Methods inherited

This class inherits methods from the following classes:

  • java.lang.Object

FocusAdapter Example

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

AwtAdapterDemo.java
package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtAdapterDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;

   public AwtAdapterDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtAdapterDemo  awtAdapterDemo = new AwtAdapterDemo();        
      awtAdapterDemo.showFocusAdapterDemo();
   }

   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showFocusAdapterDemo(){

      headerLabel.setText("Listener in action: FocusAdapter");      

      Button okButton = new Button("OK");
      Button cancelButton = new Button("Cancel");
      okButton.addFocusListener(new FocusAdapter(){
         public void focusGained(FocusEvent e) {
            statusLabel.setText(statusLabel.getText() 
            + e.getComponent().getClass().getSimpleName() 
            + " gained focus. ");
         }
      });  
      
      cancelButton.addFocusListener(new FocusAdapter(){
         public void focusLost(FocusEvent e) {
            statusLabel.setText(statusLabel.getText() 
            + e.getComponent().getClass().getSimpleName() 
            + " lost focus. ");
         }
      });  
      
      controlPanel.add(okButton);
      controlPanel.add(cancelButton);     
      mainFrame.setVisible(true);  
   }
}

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

D:\AWT>javac com\tutorialspoint\gui\AwtAdapterDemo.java

If no error comes that means compilation is successful. Run the program using following command.

D:\AWT>java com.tutorialspoint.gui.AwtAdapterDemo

Verify the following output

AWT FocusAdapter

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