Simple key press listener

With this simple tutorial we are going to see how to implement a simple key listener for your Java Desktop Application. This is a very nice tool if your application offers rich keyboard activity to the user.

In short, in order to implement a simple key listener in Java, one should perform these steps:

• Create a new class that extends KeyAdapter class.
• Override the keyPressed method to customize the handling of that specific event. Now every time the user presses a key this method will be launched.
• Use KeyEvent.getKeyChar() and KeyEvent.getKeyCode() to find out which key the user pressed.

Let’s take a look at the code snippet that follow:

package com.javacodegeeks.snippets.desktop;

import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class Main {

    public static void main(String[] argv) throws Exception {

  JTextField textField = new JTextField();

  textField.addKeyListener(new MKeyListener());

  JFrame jframe = new JFrame();

  jframe.add(textField);

  jframe.setSize(400, 350);

  jframe.setVisible(true);

    }
}

class MKeyListener extends KeyAdapter {

    @Override
    public void keyPressed(KeyEvent event) {

  char ch = event.getKeyChar();

  if (ch == 'a' ||ch == 'b'||ch == 'c' ) {

System.out.println(event.getKeyChar());

  }

  if (event.getKeyCode() == KeyEvent.VK_HOME) {

System.out.println("Key codes: " + event.getKeyCode());

  }
    }
}

 
This was an example on how to implement a simple key listener in Java.