Full screen Window won't get keyboard input using KeyListener or KeyBoardFocusManager

Question

I'm having problems with getting my KeyBoardFocusManger to work with my full screen Window. No matter what, it just wont get keyboard input. I used a System.exit(0) and a println() to look for any call to the keypressed/released/typed method, but no errors are thrown. I've tried KeyListeners; but after I read this, I changed to a KeyboardFocusManager, and the same thing still happens. I'm really getting desperate; from what I can judge, the Window is not getting focus of the keyboard?

Here is my main:

public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {

        @Override
        public void run() {
            // Determine if full-screen mode is supported directly
            GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
            GraphicsDevice gs = ge.getDefaultScreenDevice();
            if (gs.isFullScreenSupported()) {
                Frame frame = new Frame(gs.getDefaultConfiguration());
                SpaceInvaderUI spaceInvaderUI = new SpaceInvaderUI(frame);
                // Enter full-screen mode
                gs.setFullScreenWindow(spaceInvaderUI);
            } else {
                JOptionPane.showMessageDialog(null, "Does not support full screen!", "Error 0x01", JOptionPane.ERROR_MESSAGE);
                System.exit(1);
            }
        }
    });
}

and here is the UI which contains the KeyBoardFocusManger, and is added in addListeners() method:

class SpaceInvaderUI extends Window {

    private JPanel drawingPanel;
    private Image background;
    private JButton btnExit;

    public SpaceInvaderUI(Frame frame) {
        super(frame);
        try {
            background = ImageIO.read(getClass().getResourceAsStream("background.png"));
        } catch (Exception ex) {
            JOptionPane.showMessageDialog(null, "Could not extract resource: " + ex.getMessage(), "Error 0x02", JOptionPane.ERROR_MESSAGE);
            System.exit(2);
        }
        createWindow();
    }

    private void createComponents() throws HeadlessException {
        drawingPanel = new DrawingPanel(background, this);
        btnExit = new JButton("Exit");
    }

    private void createWindow() {
        createComponents();
        addListeners();
        addComponentsToWindow();
    }

    private void addComponentsToWindow() {
        add(drawingPanel, BorderLayout.CENTER);
        add(btnExit, BorderLayout.SOUTH);
    }

    private void addListeners() {
        KeyboardFocusManager manager = KeyboardFocusManager.getCurrentKeyboardFocusManager();
        manager.addKeyEventDispatcher(new MyDispatcher());
        btnExit.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent ae) {
                System.exit(0);
            }
        });
    }

    private class MyDispatcher implements KeyEventDispatcher {

        @Override
        public boolean dispatchKeyEvent(KeyEvent e) {
            if (e.getID() == KeyEvent.KEY_PRESSED) {
                System.out.println("pressed");
                System.exit(0);
            } else if (e.getID() == KeyEvent.KEY_RELEASED) {
                System.out.println("released");
                System.exit(0);
            } else if (e.getID() == KeyEvent.KEY_TYPED) {
                System.out.println("Typed");
                System.exit(0);
            }
            return false;
        }
    }
}

The exit button is just because I got tired of killing my app via taskmanager. Finally here is my panel on which the game will take place and my background is painted on:

public class DrawingPanel extends JPanel {

    private final Image background;
    private final SpaceInvaderUI invaderUI;

    DrawingPanel(Image background, SpaceInvaderUI invaderUI) {
        this.background = background;
        this.invaderUI = invaderUI;
    }

    @Override
    protected void paintComponent(Graphics grphcs) {
        super.paintComponent(grphcs);
        grphcs.drawImage(background.getScaledInstance((int) invaderUI.getWidth(), (int) invaderUI.getHeight(), Image.SCALE_SMOOTH), 0, 0, this);
    }
}

Thank you in advance.

EDIT: I have now tried using a keybinding on my drawingPanel but still nothing happens when I press f2:

class SpaceInvaderUI extends Window {

    private JPanel drawingPanel;
    private Image background;
    private JButton btnExit;

    public SpaceInvaderUI(Frame frame) {
        super(frame);
        try {
            background = ImageIO.read(getClass().getResourceAsStream("background.png"));
        } catch (Exception ex) {
            JOptionPane.showMessageDialog(null, "Could not extract resource: " + ex.getMessage(), "Error 0x02", JOptionPane.ERROR_MESSAGE);
            System.exit(2);
        }
        createWindow();
    }

    private void createComponents() throws HeadlessException {
        drawingPanel = new DrawingPanel(background, this);
        btnExit = new JButton("Exit");
    }

    private void createWindow() {
        createComponents();
        addListeners();
        addComponentsToWindow();
    }

    private void addComponentsToWindow() {
        add(drawingPanel, BorderLayout.CENTER);
        add(btnExit, BorderLayout.SOUTH);
    }

    private void addListeners() {
        Action exit = new AbstractAction() {

            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        };
        drawingPanel.getInputMap().put(KeyStroke.getKeyStroke("F2"),
                exit);
        btnExit.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent ae) {
                System.exit(0);
            }
        });
    }
}

Answer 1

Why are you using AWT components in your Swing GUI? I fear (but don't know for sure) that by doing this, you may be losing some of the Swing functionality.

If you are only capturing select key select key strokes to control the game, consider using Key Bindings.

Edit:
No, the AWT components aren't at fault, but still probably should not be used.

Edit 2:
Your top level Window is not focused for some reason. Continuing to test code...

Edit 3:
Using a JFrame worked for me:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Test3 {
   public static void main(String[] args) {
      EventQueue.invokeLater(new Runnable() {

         @Override
         public void run() {
            GraphicsEnvironment ge = GraphicsEnvironment
                  .getLocalGraphicsEnvironment();
            GraphicsDevice gs = ge.getDefaultScreenDevice();
            if (gs.isFullScreenSupported()) {
               SpaceInvaderUI spaceInvaderUI = new SpaceInvaderUI(gs.getDefaultConfiguration());
               gs.setFullScreenWindow(spaceInvaderUI);
            } else {
               JOptionPane.showMessageDialog(null,
                     "Does not support full screen!", "Error 0x01",
                     JOptionPane.ERROR_MESSAGE);
               System.exit(1);
            }
         }
      });
   }
}

// class SpaceInvaderUI extends JWindow {
class SpaceInvaderUI extends JFrame {

   private JPanel drawingPanel;
   private Image background;
   private JButton btnExit;

   public SpaceInvaderUI(GraphicsConfiguration gc) {
      super(gc);
      createWindow();
      addKeyBindings();
      setUndecorated(true);
   }

   private void addKeyBindings() {
      int condition = JPanel.WHEN_IN_FOCUSED_WINDOW;
      InputMap inputMap = drawingPanel.getInputMap(condition );
      ActionMap actionMap = drawingPanel.getActionMap();

      boolean released = false;
      KeyStroke upArrowKeyStrokePressed = KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, released );
      String upArrowPressed = "up arrow pressed";
      inputMap.put(upArrowKeyStrokePressed , upArrowPressed);
      actionMap.put(upArrowPressed, new AbstractAction() {

         @Override
         public void actionPerformed(ActionEvent arg0) {
            System.out.println("up arrow pressed");
         }
      });

      released = true;
      String upArrowReleased = "up arrow released";
      KeyStroke upArrowKeyStrokeReleased = KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, released );
      inputMap.put(upArrowKeyStrokeReleased , upArrowReleased);
      actionMap.put(upArrowReleased , new AbstractAction() {

         @Override
         public void actionPerformed(ActionEvent arg0) {
            System.out.println("up arrow released");
         }
      });

   }

   private void createComponents() throws HeadlessException {
      drawingPanel = new DrawingPanel(background, this);
      btnExit = new JButton("Exit");
   }

   private void createWindow() {
      createComponents();
      addListeners();
      addComponentsToWindow();
   }

   private void addComponentsToWindow() {
      add(drawingPanel, BorderLayout.CENTER);
      add(btnExit, BorderLayout.SOUTH);
   }

   private void addListeners() {
//      KeyboardFocusManager manager = KeyboardFocusManager
//            .getCurrentKeyboardFocusManager();
//      manager.addKeyEventDispatcher(new MyDispatcher());
      btnExit.addActionListener(new ActionListener() {

         @Override
         public void actionPerformed(ActionEvent ae) {
            System.exit(0);
         }
      });
   }
//
//   private class MyDispatcher implements KeyEventDispatcher {
//
//      @Override
//      public boolean dispatchKeyEvent(KeyEvent e) {
//         System.out.println("in dispatch. KeyEvent := " + e);
//         if (e.getID() == KeyEvent.KEY_PRESSED) {
//            System.out.println("pressed");
//            System.exit(0);
//         } else if (e.getID() == KeyEvent.KEY_RELEASED) {
//            System.out.println("released");
//            System.exit(0);
//         } else if (e.getID() == KeyEvent.KEY_TYPED) {
//            System.out.println("Typed");
//            System.exit(0);
//         }
//         return false;
//      }
//   }
}

class DrawingPanel extends JPanel {

   private final Image background;
   private final SpaceInvaderUI invaderUI;

   DrawingPanel(Image background, SpaceInvaderUI invaderUI) {
      this.background = background;
      this.invaderUI = invaderUI;
      setBackground(Color.pink);
   }

   @Override
   protected void paintComponent(Graphics grphcs) {
      super.paintComponent(grphcs);
   }
}

Answer 2

As shown in this related FullScreenTest, you can use the same Action instance for the button and the key binding.

Addendum: @nIcE cOw asks, Can we add more than one key on the same JComponent by using InputMap and ActionMap, and use the same AbstractAction class?

Yes, multiple key bindings are possible; I sometimes invoke doClick() to get the audio-visual feedback, as shown here.