AWT KeyAdapter Class

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Introduction

The class KeyAdapter is an abstract (adapter) class for receiving keyboard 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.KeyAdapter class:

public abstract class KeyAdapter
   extends Object
      implements KeyListener

Class constructors

S.N.Constructor & Description
1KeyAdapter()

Class methods

S.N.Method & Description
1void keyPressed(KeyEvent e)
Invoked when a key has been pressed.
2void keyReleased(KeyEvent e)
Invoked when a key has been released.
3void keyTyped(KeyEvent e)
Invoked when a key has been typed.

Methods inherited

This class inherits methods from the following classes:

  • java.lang.Object

KeyAdapter 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.showKeyAdapterDemo();
   }

   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 showKeyAdapterDemo(){
      headerLabel.setText("Listener in action: KeyAdapter");      

      final TextField textField = new TextField(10);

      textField.addKeyListener(new KeyAdapter() {
         public void keyPressed(KeyEvent e) {                
            if(e.getKeyCode() == KeyEvent.VK_ENTER){
               statusLabel.setText("Entered text: " + textField.getText());
            }
         }        
      });
      Button okButton = new Button("OK");
      okButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            statusLabel.setText("Entered text: " + textField.getText());                
         }
      });

      controlPanel.add(textField);
      controlPanel.add(okButton);    
      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 KeyAdapter

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