Key input ignored after clicking on components.

Newbie & Debugging Questions
#1

Hey,

I’ve just started to notice that whenever I click on anything other than my JFrame after starting my program for testing the key input is completely ignored, even if I click on the JFrame again. The KeyListener, which is below, is added to the JFrame at the start of the program. I don’t see any reason for the key listener to just stop working when I click on my canvas or JTextArea.

package valkryst.core;

import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

/**
 * This class handles all keyboard input from the user.
 * 
 * @author Valkryst
 * --- Last Edit 23-Sep-2013
 */
public class InputHandler implements KeyListener {
	private boolean[] isPressed = new boolean[128];
	
	/**
	 * Checks if the specified key is currently pressed.
	 * @param x The keyEvent.getKeyCode() number of the key.
	 * @return Return whether the specified key is pressed or not.
	 */
	public boolean isKeyPressed(final int x) {
		return isPressed[x];
	}
	
	/**
	 * Forces the specified key to be set as released.
	 * @param x The keyEvent.getKeyCode() number of the key.
	 */
	public void forceRelease(final int x) {
		if (x < isPressed.length)
			isPressed[x] = false;
	}

	/**
	 * When a key is pressed then set that key as pressed.
	 */
	public void keyPressed(final KeyEvent e) {
		final int KEY_CODE = e.getKeyCode();
		if (KEY_CODE < isPressed.length)
			isPressed[KEY_CODE] = true;
	}
	
	/**
	 * When a key is released then set that key as released.
	 */
	public void keyReleased(final KeyEvent e) {
		final int KEY_CODE = e.getKeyCode();
		if (KEY_CODE < isPressed.length)
			isPressed[KEY_CODE] = false;
	}

	public void keyTyped(final KeyEvent e) {
	}
}


package valkryst.core.graphics;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.TextArea;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JFrame;

import valkryst.core.Audio;
import valkryst.core.InputHandler;
import valkryst.systems.Message;

/**
 * @author Valkryst
 * --- Last Edit 07-Oct-2013
 */
public class Frame extends JFrame{
	private static final long serialVersionUID = -4612661261769049289L;
	
	public final static int WIDTH = 300;
	public final static int HEIGHT = 168; // 
	public final static int SCALE = 3;
	public final static InputHandler INPUT = new InputHandler();
	
	public Frame(final Screen screen) {
		setResizable(true); //You can set this to true, the graphics scale up.
		setTitle("Temp");
		add(screen);
		pack();
		setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);

		addWindowListener(new WindowAdapter() { // Runs before the game exits.
			public void windowClosing(WindowEvent e) {
				Audio.shutdown();
				System.exit(0);
			}
		});
		
		addKeyListener(INPUT);
		setLayout(new BorderLayout());
		add(screen, BorderLayout.CENTER);
		setLocationRelativeTo(null);
		setPreferredSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));
		setMinimumSize(new Dimension(WIDTH, HEIGHT));
		requestFocus();
		setFocusable(true);
		
		TextArea textArea = new TextArea();
		textArea.setEditable(false);
		textArea.setFocusable(false);
		textArea.setCursor(getCursor());
		textArea.setPreferredSize(new Dimension(WIDTH, HEIGHT + (HEIGHT/2)));
		textArea.setMinimumSize(new Dimension(50, 100));
		textArea.setMaximumSize(new Dimension(300, 600));
		textArea.setBackground(Color.WHITE);
		Message.setTextArea(textArea);
		add(textArea, BorderLayout.SOUTH);
		
		pack();
		
		setVisible(true);
		
		screen.start(); 
	}
}

Sorry for the terrible description of what’s going on, I’ll improve it when I get back from class. Thanks for any replies.