Jak używać KeyEventDispatcher

Question

Próbowałem zrobić klona Ponga jako swego rodzaju projekt dla początkujących, a ja uderzyłem w blokadę. Udało mi się dojść do punktu obsługi klawiatury, ale opóźnienie powtórzenia klawiatury się pojawi. Nie znalazłem żadnego użytecznego sposobu użycia KeyEventDispatcher. Nie zainicjuje nawet metody dispatchKeyEvent(). Jak miałbym to wykorzystać?

Z góry dziękuję.

PS: Oto moje źródło tej pory: http://pastebin.com/N9fLMzFT

Answer 1

trzeba szukać KeyBindings

import java.awt.*; 
import java.awt.event.*; 
import java.awt.image.BufferedImage; 
import java.io.IOException; 
import java.net.*; 
import java.util.HashMap; 
import java.util.Map; 
import javax.imageio.ImageIO; 
import javax.swing.*; 

public class MoveIcon extends JPanel { 

    private static final long serialVersionUID = 1L; 
    private static final String IMAGE_PATH = "http://duke.kenai.com/misc/Bullfight.jpg"; 
    private static final String IMAGE_PATH_PLAYER = "http://duke.kenai.com/iconSized/duke4.gif"; 
    public static final int STEP = 3; 
    private static final int TIMER_DELAY = STEP * 8; 
    private BufferedImage bkgrndImage = null; 
    private BufferedImage playerImage = null; 
    private Map<Direction, Boolean> directionMap = new HashMap<Direction, Boolean>(); 
    private int playerX = 0; 
    private int playerY = 0; 

    enum Direction { 

     UP(KeyEvent.VK_UP, 0, -1), DOWN(KeyEvent.VK_DOWN, 0, 1), 
     LEFT(KeyEvent.VK_LEFT, -1, 0), RIGHT(KeyEvent.VK_RIGHT, 1, 0); 
     private int keyCode; 
     private int xDirection; 
     private int yDirection; 

     private Direction(int keyCode, int xDirection, int yDirection) { 
      this.keyCode = keyCode; 
      this.xDirection = xDirection; 
      this.yDirection = yDirection; 
     } 

     public int getKeyCode() { 
      return keyCode; 
     } 

     public int getXDirection() { 
      return xDirection; 
     } 

     public int getYDirection() { 
      return yDirection; 
     } 
    } 

    public MoveIcon() { 
     try { 
      URL bkgrdImageURL = new URL(IMAGE_PATH); 
      URL playerImageURL = new URL(IMAGE_PATH_PLAYER); 
      bkgrndImage = ImageIO.read(bkgrdImageURL); 
      playerImage = ImageIO.read(playerImageURL); 
      setPreferredSize(new Dimension(bkgrndImage.getWidth(), bkgrndImage.getHeight())); 
     } catch (MalformedURLException e) { 
      e.printStackTrace(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
     for (Direction direction : Direction.values()) { 
      directionMap.put(direction, false); 
     } 
     setKeyBindings(); 
     Timer timer = new Timer(TIMER_DELAY, new TimerListener()); 
     timer.start(); 
    } 

    private void setKeyBindings() { 
     InputMap inMap = getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW); 
     ActionMap actMap = getActionMap(); 
     for (final Direction direction : Direction.values()) { 
      KeyStroke pressed = KeyStroke.getKeyStroke(direction.getKeyCode(), 0, false); 
      KeyStroke released = KeyStroke.getKeyStroke(direction.getKeyCode(), 0, true); 
      inMap.put(pressed, direction.toString() + "pressed"); 
      inMap.put(released, direction.toString() + "released"); 
      actMap.put(direction.toString() + "pressed", new AbstractAction() { 

       private static final long serialVersionUID = 1L; 

       @Override 
       public void actionPerformed(ActionEvent e) { 
        directionMap.put(direction, true); 
       } 
      }); 
      actMap.put(direction.toString() + "released", new AbstractAction() { 

       private static final long serialVersionUID = 1L; 

       @Override 
       public void actionPerformed(ActionEvent e) { 
        directionMap.put(direction, false); 
       } 
      }); 
     } 

    } 

    @Override 
    protected void paintComponent(Graphics g) { 
     super.paintComponent(g); 
     if (bkgrndImage != null) { 
      g.drawImage(bkgrndImage, 0, 0, null); 
     } 
     if (playerImage != null) { 
      g.drawImage(playerImage, playerX, playerY, null); 
     } 
    } 

    private class TimerListener implements ActionListener { 

     @Override 
     public void actionPerformed(ActionEvent e) { 
      boolean moved = false; 
      for (Direction direction : Direction.values()) { 
       if (directionMap.get(direction)) { 
        playerX += STEP * direction.getXDirection(); 
        playerY += STEP * direction.getYDirection(); 
        moved = true; 
       } 
      } 
      if (moved) { 
       int x = playerX - 2 * STEP; 
       int y = playerY - 2 * STEP; 
       int w = playerImage.getWidth() + 4 * STEP; 
       int h = playerImage.getHeight() + 4 * STEP; 
       MoveIcon.this.repaint(x, y, w, h); // !! repaint just the player 
      } 
     } 
    } 

    private static void createAndShowUI() { 
     JFrame frame = new JFrame("MoveIcon"); 
     frame.getContentPane().add(new MoveIcon()); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     frame.pack(); 
     frame.setLocationRelativeTo(null); 
     frame.setVisible(true); 
    } 

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

      @Override 
      public void run() { 
       createAndShowUI(); 
      } 
     }); 
    } 
}