public BallsFrame() throws HeadlessException {
super("Funny balls");
setLayout(new BorderLayout());
executorService = Executors.newScheduledThreadPool(1);
ballsPanel =
new JPanel() {
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (blueBallVisible) {
g.setColor(Color.BLUE);
g.fillOval(blueBall.x, getHeight() / 2, BALL_DIAGONAL, BALL_DIAGONAL);
}
g.setColor(Color.RED);
g.fillOval(redBall.x, getHeight() / 2, BALL_DIAGONAL, BALL_DIAGONAL);
}
};
add(ballsPanel, BorderLayout.CENTER);
blueBallSwitch = new JCheckBox("Collision", true);
blueBallSwitch.addItemListener(
e -> {
if (blueBallVisible = blueBallSwitch.isSelected()) {
int x;
do x = random.nextInt(getWidth() - BALL_DIAGONAL);
while (redBall.x <= x && x <= redBall.rightX()
|| redBall.x <= x + BALL_DIAGONAL && x + BALL_DIAGONAL <= redBall.rightX());
blueBall.x = x;
}
});
add(blueBallSwitch, BorderLayout.SOUTH);
blueBallVisible = true;
moveToRight = true;
setSize(500, 500);
}
private void startAnimation() {
redBall = new Ball(1);
blueBall = new Ball(getWidth() / 2);
executorService.scheduleAtFixedRate(
() -> {
if (redBall.rightX() >= getWidth()
|| redBall.x <= 0
|| blueBallVisible && redBall.intersectsWith(blueBall)) moveToRight = !moveToRight;
redBall.x += moveToRight ? 1 : -1;
ballsPanel.repaint();
},
1,
5,
TimeUnit.MILLISECONDS);
}
public boolean intersectsWith(Ball other) {
return this.x <= other.x && other.x <= this.rightX()
|| this.x <= other.rightX() && other.rightX() <= this.rightX();
}