Help with pong game

[Eric]

Hi , I am trying to build a pong game. I just need to find some type of Keylistener that will help me know what the person typed. Like I know what they typed if I add a textbox, but I want them to type anywhere in my window and for my program to still be able to know what they did.

Eric

[Marcus]

There are several ways to approach this.

Implement KeyListener:

 import java.applet.Applet;
 
 import java.awt.event.KeyListener;
 import java.awt.event.KeyEvent;
 
 public class KeyListenerExample extends Applet implements KeyListener {
     public void init() {
         addKeyListener(this);
     }
     
     public void keyPressed(KeyEvent e) {
         System.out.println("keyPressed: " + e.getKeyChar());
     }
     
     public void keyTyped(KeyEvent e) {
         System.out.println("keyTyped: " + e.getKeyChar());
     }
     
     public void keyReleased(KeyEvent e) {
         System.out.println("keyReleased: " + e.getKeyChar());
     }
 }

Create an inner private class that extends a class that implements KeyListener, or that implements KeyListener itself:

import java.applet.Applet;
 
 import java.awt.event.KeyAdapter;
 import java.awt.event.KeyEvent;
 
 public class KeyListenerExample extends Applet {
     public void init() {
         addKeyListener(new MyKeyListener());
     }
     
     private class MyKeyListener extends KeyAdapter {
         public void keyPressed(KeyEvent e) {
             System.out.println("keyPressed: " + e.getKeyChar());
         }
     
         public void keyTyped(KeyEvent e) {
             System.out.println("keyTyped: " + e.getKeyChar());
         }
     
         public void keyReleased(KeyEvent e) {
             System.out.println("keyReleased: " + e.getKeyChar());
         }
     }
 }

Create an anonymous inner class:

import java.applet.Applet;
 
 import java.awt.event.KeyListener;
 import java.awt.event.KeyEvent;
 
 public class KeyListenerExample extends Applet {
     public void init() {
         addKeyListener(new KeyListener() {
             public void keyPressed(KeyEvent e) {
                 System.out.println("keyPressed: " + e.getKeyChar());
             }
             
             public void keyTyped(KeyEvent e) {
                 System.out.println("keyTyped: " + e.getKeyChar());
             }
             
             public void keyReleased(KeyEvent e) {
                 System.out.println("keyReleased: " + e.getKeyChar());
             }
         });
     }
 }

Greetings.

Marcus

[Felissa]

If you look at the JFrame API, you'll notice that it inherits from Component, which provides the addKeyListener(KeyListener) method.
JFrame

import java.awt.Container;
 import java.awt.Dimension;
 import java.awt.event.KeyListener;
 import java.awt.event.KeyEvent;
 
 import javax.swing.JFrame;
 import javax.swing.JPanel;
 
 public class KeyListenerExample extends JFrame {
     public KeyListenerExample() {
         super ("KeyListener Example");
         
         JPanel panel = (JPanel) getContentPane();
         panel.setPreferredSize(new Dimension(800, 600));
         panel.setLayout(null);
         
         pack();
         setResizable(false);
         setVisible(true);
 
         addKeyListener(new KeyListener() {
             public void keyPressed(KeyEvent e) {
                 System.out.println("keyPressed: " + e.getKeyChar());
             }
             
             public void keyTyped(KeyEvent e) {
                 System.out.println("keyTyped: " + e.getKeyChar());
             }
             
             public void keyReleased(KeyEvent e) {
                 System.out.println("keyReleased: " + e.getKeyChar());
             }
         });
      }
     
     static public void main(String[] args) {
          new KeyListenerExample();
      }
 }

Greetings.

Felissa