Repaint() Methode Aufruf in einer anderen Klasse

Question

Ich habe ein Problem mit repaint() Methode in meinem Java Code. Ich möchte es in einer anderen class anrufen, aber ich kann nicht, etwas überhaupt nicht funktioniert. Ich habe in Foren gesucht, aber nichts konnte mir helfen.

Mein Hauptclass:

public class Main { 

public static Main main; 
public static JFrame f; 
public Main(){ 

} 

public static void main(String[] args) { 
    main = new Main(); 

    f = new JFrame(); 
    Ball b = new Ball(); 

    f.getContentPane().setBackground(Color.GRAY); 

    f.add(b); 
    f.setSize(500, 500); 
    f.setLocationRelativeTo(null); 
    f.setTitle("Test"); 
    f.setVisible(true); 
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    f.addMouseMotionListener(b); 
    f.addKeyListener(new Key()); 


} 
} 

Kugelclass wo ich 2DGraphics zum Bewegen Formen erstellt:

public class Ball extends JLabel implements MouseMotionListener{ 

public Ball(){ 

} 

public static double x = 10; 
public static double y = 10; 
public static double width = 40; 
public static double height = 40; 

String nick; 
boolean isEllipse = true; 

public void paintComponent(Graphics g){ 
    super.paintComponent(g); 

    Graphics2D g2d = (Graphics2D) g; 
    if(isEllipse){ 
     Ellipse2D e2d = new Ellipse2D.Double(x, y, width, height); 
     g2d.setColor(Color.RED); 
     g2d.fill(e2d); 
    } 
    else{ 
     Rectangle2D r2d = new Rectangle2D.Double(x, y, width, height); 
     g2d.setColor(Color.GREEN); 
     g2d.fill(r2d); 
    } 

} 

@Override 
public void mouseDragged(MouseEvent e) { 
    isEllipse = false; 
    x = e.getX() - 30; 
    y = e.getY() - 40; 
    this.repaint(); 
} 

@Override 
public void mouseMoved(MouseEvent e) { 
    x = e.getX() - 30; 
    y = e.getY() - 40; 
    isEllipse = true; 
    this.repaint(); 
} 
} 

Und Keyclass wo ich KeyListener die Formen für Bewegung setzen durch Tastendruck:

public class Key extends Ball implements KeyListener { 

public Key() { 
} 

@SuppressWarnings("static-access") 
@Override 
public void keyPressed(KeyEvent e) { 

    if(e.getKeyCode() == KeyEvent.VK_W){ 
     super.x += 10; 
     super.repaint(); 
     System.out.println("x: " + super.x); 
    } 
} 

@Override 
public void keyReleased(KeyEvent e) { 
    // TODO Auto-generated method stub 

} 

@Override 
public void keyTyped(KeyEvent e) { 
    // TODO Auto-generated method stub 

} 
} 

Aber etwas ist mit diesem Code falsch: Super Methode für nicht Keyclass funktioniert. Alles in Ballclass funktioniert gut. Wo ist das Problem?

Answer 1

Super funktioniert gut, aber Ihre Interpretation dessen, was es tut, ist falsch. Ihr Problem besteht darin, dass Sie versuchen, Vererbung zu verwenden, um ein Problem zu lösen, das nicht durch Vererbung gelöst wird. Sie müssen repaint() auf der tatsächlichen visualisierten und verwendeten Ball-Instanz aufrufen, nicht auf einer Instanz einer völlig anderen Klasse, Key, die sich unangemessen von Ball erstreckt. Zunächst einmal machen Sie Key nicht Ball erweitern, in einem echten Ball Verweis in Key übergeben und die Lösung wird daraus fallen.

Vielleicht so etwas tun:

f.addKeyListener(new Key(b)); 

und

public class Key implements KeyListener { 
    private Ball ball; 

    public Key(Ball ball) { 
     this.ball = ball; 
    } 

    public void keyPressed(KeyEvent e) { 

     if(e.getKeyCode() == KeyEvent.VK_W){ 
      b.incrX(10); // give Ball a public method for this 
      b.repaint(); 
      // System.out.println("x: " + super.x); 
     } 
    } 

    // .... etc... 

Hinweis, ich selbst, ich Key Bindings für diese verwenden würde, kein KeyListener, da dann würde ich nicht haben, Fuz mit Tastatur Fokus.

Zum Beispiel:

import java.awt.Color; 
import java.awt.Dimension; 
import java.awt.Graphics; 
import java.awt.Graphics2D; 
import java.awt.Point; 
import java.awt.RenderingHints; 
import java.awt.event.*; 

import javax.swing.AbstractAction; 
import javax.swing.ActionMap; 
import javax.swing.InputMap; 
import javax.swing.JComponent; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.KeyStroke; 
import javax.swing.SwingUtilities; 

public class MoveBall { 
    private static final int PREF_W = 500; 
    private static final int PREF_H = PREF_W; 

    private static void createAndShowGui() { 
     BallPanel ballPanel = new BallPanel(PREF_W, PREF_H); 
     MyMouse myMouse = new MyMouse(ballPanel); 
     ballPanel.addMouseListener(myMouse); 
     ballPanel.addMouseMotionListener(myMouse); 
     new CreateKeyBindings(ballPanel); 


     JFrame frame = new JFrame("MoveBall"); 
     frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); 
     frame.getContentPane().add(ballPanel); 
     frame.pack(); 
     frame.setLocationByPlatform(true); 
     frame.setVisible(true); 
    } 

    public static void main(String[] args) { 
     SwingUtilities.invokeLater(() -> { 
      createAndShowGui(); 
     }); 
    } 
} 

@SuppressWarnings("serial") 
class BallPanel extends JPanel { 

    private static final Color ELLIPSE_COLOR = Color.RED; 
    private static final Color SQUARE_COLOR = Color.GREEN; 
    private static final int BALL_WIDTH = 40; 
    private int prefW; 
    private int prefH; 
    private boolean isEllipse = true; 
    private int ballX; 
    private int ballY; 

    public BallPanel(int prefW, int prefH) { 
     this.prefW = prefW; 
     this.prefH = prefH; 
    } 

    public boolean isEllipse() { 
     return isEllipse; 
    } 

    public void setEllipse(boolean isEllipse) { 
     this.isEllipse = isEllipse; 
    } 

    public int getBallX() { 
     return ballX; 
    } 

    public void setBallX(int ballX) { 
     this.ballX = ballX; 
    } 

    public void setXY(int x, int y) { 
     ballX = x; 
     ballY = y; 
     repaint(); 
    } 

    public void setXYCenter(int x, int y) { 
     ballX = x - BALL_WIDTH/2; 
     ballY = y - BALL_WIDTH/2; 
     repaint(); 
    } 

    public void setXYCenter(Point p) { 
     setXYCenter(p.x, p.y); 
    } 

    public int getBallY() { 
     return ballY; 
    } 

    public void setBallY(int ballY) { 
     this.ballY = ballY; 
    } 

    public void incrementBallX(int x) { 
     ballX += x; 
     repaint(); 
    } 

    public void incrementBallY(int y) { 
     ballY += y; 
     repaint(); 
    } 



    @Override 
    protected void paintComponent(Graphics g) { 
     super.paintComponent(g); 
     Graphics2D g2 = (Graphics2D) g; 
     g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 
     if (isEllipse) { 
      g2.setColor(ELLIPSE_COLOR); 
      g2.fillOval(ballX, ballY, BALL_WIDTH, BALL_WIDTH); 
     } else { 
      g2.setColor(SQUARE_COLOR); 
      g2.fillOval(ballX, ballY, BALL_WIDTH, BALL_WIDTH); 
     } 
    } 

    @Override 
    public Dimension getPreferredSize() { 
     if (isPreferredSizeSet()) { 
      return super.getPreferredSize(); 
     } 
     return new Dimension(prefW, prefH); 
    } 
} 

class MyMouse extends MouseAdapter { 

    private BallPanel ballPanel; 

    public MyMouse(BallPanel ballPanel) { 
     this.ballPanel = ballPanel; 
    } 

    @Override 
    public void mousePressed(MouseEvent e) { 
     ballPanel.setXYCenter(e.getPoint()); 
    } 

    @Override 
    public void mouseDragged(MouseEvent e) { 
     ballPanel.setXYCenter(e.getPoint()); 
    } 

    @Override 
    public void mouseReleased(MouseEvent e) { 
     ballPanel.setXYCenter(e.getPoint()); 
    } 

} 

enum Direction { 
    UP(KeyEvent.VK_UP), DOWN(KeyEvent.VK_DOWN), LEFT(KeyEvent.VK_LEFT), RIGHT(KeyEvent.VK_RIGHT); 

    private int key; 

    private Direction(int key) { 
     this.key = key; 
    } 

    public int getKey() { 
     return key; 
    } 
} 

// Actions for the key binding 
@SuppressWarnings("serial") 
class MyKeyAction extends AbstractAction { 
    private static final int STEP_DISTANCE = 5; 
    private BallPanel ballPanel; 
    private Direction direction; 

    public MyKeyAction(BallPanel ballPanel, Direction direction) { 
     this.ballPanel = ballPanel; 
     this.direction = direction; 
    } 

    @Override 
    public void actionPerformed(ActionEvent e) { 
     switch (direction) { 
     case UP: 
      ballPanel.incrementBallY(-STEP_DISTANCE); 
      break; 
     case DOWN: 
      ballPanel.incrementBallY(STEP_DISTANCE); 
      break; 
     case LEFT: 
      ballPanel.incrementBallX(-STEP_DISTANCE); 
      break; 
     case RIGHT: 
      ballPanel.incrementBallX(STEP_DISTANCE); 
      break; 

     default: 
      break; 
     } 
    } 
} 

class CreateKeyBindings { 

    private BallPanel ballPanel; 

    public CreateKeyBindings(BallPanel ballPanel) { 
     this.ballPanel = ballPanel; 
     int condition = JComponent.WHEN_IN_FOCUSED_WINDOW; 
     InputMap inputMap = ballPanel.getInputMap(condition); 
     ActionMap actionMap = ballPanel.getActionMap(); 

     for (Direction direction : Direction.values()) { 
      KeyStroke keyStroke = KeyStroke.getKeyStroke(direction.getKey(), 0); 
      String keyString = keyStroke.toString(); 
      inputMap.put(keyStroke, keyString); 
      actionMap.put(keyString, new MyKeyAction(ballPanel, direction)); 
     } 
    } 

}