Hello I created a little application that moves a ball that I've painted in Java but uses ActionListener, now I am new to Java and I would like to use mey keyboard to do this. What method should be used for this? I have seen people saying KeyBindings and some people say KeyListener I tried to figure out something myself but it doesn't work. the code I've wroten is as followed:
@Override
public void keyPressed(KeyEvent e) {
System.out.println("keyPressed");
char c = e.getKeyChar();
if( c == KeyEvent.VK_LEFT ) {
pos -= 10;
}
repaint();
}
@Override
public void keyReleased(KeyEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void keyTyped(KeyEvent arg0) {
System.out.println("keyTyped");
char v = arg0.getKeyChar();
if( v == KeyEvent.KEY_LOCATION_RIGHT ) {
pos -= 10;
}
repaint();
}
Okay, took a little longer then I'd hoped (fighting fires ;))
This basically uses a combination of Actions, key bindings and buttons...
Now I separated the ball rendering out to a separate class, this just allows me the chance to change how the ball is rendered without effecting the container...You obviously will have your own rendering process.
MAIN
public class BallsUp {
public static void main(String[] args) {
new BallsUp();
}
public BallsUp() {
JFrame frame = new JFrame();
frame.setTitle("Balls up");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
frame.setLocationRelativeTo(null);
BallPane ballPane = new BallPane();
JPanel mainPane = new JPanel(new BorderLayout());
mainPane.add(ballPane);
JPanel north = new JPanel(new GridBagLayout());
north.add(new JButton(new BallPane.UpAction(ballPane)));
mainPane.add(north, BorderLayout.NORTH);
JPanel south = new JPanel(new GridBagLayout());
south.add(new JButton(new BallPane.DownAction(ballPane)));
mainPane.add(south, BorderLayout.SOUTH);
JPanel east = new JPanel(new GridBagLayout());
east.add(new JButton(new BallPane.RightAction(ballPane)));
mainPane.add(east, BorderLayout.EAST);
JPanel west = new JPanel(new GridBagLayout());
west.add(new JButton(new BallPane.LeftAction(ballPane)));
mainPane.add(west, BorderLayout.WEST);
frame.add(mainPane);
frame.setVisible(true);
}
}
The Ball Pane
public class BallPane extends JPanel {
protected static final int DISTANCE = 10;
private Ball ball;
private Timer resizeTimer;
private ComponentListener componentListener;
public BallPane() {
setBall(new Ball());
InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
ActionMap am = getActionMap();
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0), "goDown");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0), "goUp");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0), "goLeft");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0), "goRight");
am.put("goDown", new DownAction(this));
am.put("goUp", new UpAction(this));
am.put("goLeft", new LeftAction(this));
am.put("goRight", new RightAction(this));
setFocusable(true);
requestFocusInWindow();
}
public void setBall(Ball ball) {
this.ball = ball;
}
public Ball getBall() {
return ball;
}
@Override
public void addNotify() {
super.addNotify();
componentListener = new ComponentAdapter() {
@Override
public void componentResized(ComponentEvent e) {
resizeTimer.restart();
}
};
resizeTimer = new Timer(250, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
removeComponentListener(componentListener);
Point p = new Point(getWidth() / 2, getHeight() / 2);
getBall().setLocation(p);
resizeTimer.stop();
resizeTimer = null;
repaint();
}
});
resizeTimer.setRepeats(false);
resizeTimer.setCoalesce(true);
addComponentListener(componentListener);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Ball ball = getBall();
if (ball != null) {
Graphics2D g2d = (Graphics2D) g;
ball.paint(g2d);
}
}
public static abstract class AbstractBallAction extends AbstractAction {
private BallPane pane;
public AbstractBallAction(BallPane pane) {
this.pane = pane;
}
public BallPane getBallPane() {
return pane;
}
public int getXDistance() {
return 0;
}
public int getYDistance() {
return 0;
}
@Override
public void actionPerformed(ActionEvent e) {
BallPane pane = getBallPane();
Ball ball = pane.getBall();
Point location = ball.getLocation();
location.y += getYDistance();
location.x += getXDistance();
if (location.y < (ball.getWidth() / 2)) {
location.y = (ball.getWidth() / 2);
} else if (location.y > pane.getHeight() - 1 - ball.getHeight()) {
location.y = pane.getHeight() - ball.getHeight();
}
if (location.x < (ball.getHeight() / 2)) {
location.x = (ball.getHeight() / 2);
} else if (location.x > pane.getWidth() - 1 - ball.getWidth()) {
location.x = pane.getWidth() - ball.getWidth();
}
ball.setLocation(location);
pane.repaint();
}
}
public static class UpAction extends AbstractBallAction {
public UpAction(BallPane pane) {
super(pane);
putValue(NAME, "Up");
}
@Override
public int getYDistance() {
return -DISTANCE;
}
}
public static class DownAction extends AbstractBallAction {
public DownAction(BallPane pane) {
super(pane);
putValue(NAME, "Down");
}
@Override
public int getYDistance() {
return DISTANCE;
}
}
public static class LeftAction extends AbstractBallAction {
public LeftAction(BallPane pane) {
super(pane);
putValue(NAME, "Left");
}
@Override
public int getXDistance() {
return -DISTANCE;
}
}
public static class RightAction extends AbstractBallAction {
public RightAction(BallPane pane) {
super(pane);
putValue(NAME, "Right");
}
@Override
public int getXDistance() {
return DISTANCE;
}
}
}
The Ball
public class Ball {
private Shape shape;
private Point p;
public Ball() {
shape = new Ellipse2D.Float(0, 0, 10, 10);
}
public void setLocation(Point p) {
this.p = p;
}
public Point getLocation() {
return p;
}
public Shape getShape() {
return shape;
}
public void paint(Graphics2D g2d) {
Point p = getLocation();
if (p != null) {
g2d = (Graphics2D) g2d.create();
g2d.setColor(Color.BLUE);
Shape shape = getShape();
int x = (int) p.x - (shape.getBounds().width / 2);
int y = (int) p.y - (shape.getBounds().height / 2);
g2d.translate(x, y);
g2d.fill(shape);
g2d.dispose();
}
}
public int getWidth() {
return getShape().getBounds().width;
}
public int getHeight() {
return getShape().getBounds().width;
}
}
I appologise, I got a little carried away, but this basic premise works ;)