This is the solution to step 3 of the Stanford CS106A Breakout game assignment, creating a ball and making it bounce off the walls

BreakoutCreateBounceBall

//These are declared outside the method, but in the class. 

/**Ball velocity*/	
	private double vx, vy;
	
/**Random number generator for vx*/	
	private RandomGenerator rgen = RandomGenerator.getInstance();
	
/** Animation delay or paust time between ball moves */	
	private static final int DELAY = 10;

//this part is inside the method. 

//adding an individual ball object
	private GOval ball;

//ball set-up
	private void drawBall() {
		double x = getWidth()/2 - BALL_RADIUS;
		double y = getHeight()/2 - BALL_RADIUS;
		ball = new GOval(x, y, BALL_RADIUS, BALL_RADIUS);
		ball.setFilled(true);
		add(ball);
	}

private void playGame() {
		waitForClick();
		getBallVelocity();
		while (true) {
			moveBall();
		}
	}
	
	
	
	private void getBallVelocity() {
		vy = 3.0;
		vx = rgen.nextDouble(1.0, 3.0);
		if (rgen.nextBoolean(0.5)) {
			vx = -vx; 
		}
		
	}
	
	private void moveBall() {
		ball.move(vx, vy);
		//check for walls
		//need to get vx and vy at the point closest to 0 or the other edge
		if ((ball.getX() - vx <= 0 && vx < 0 )|| (ball.getX() + vx >= (getWidth() - BALL_RADIUS*2) && vx>0)) {
			vx = -vx;
		}
		if ((ball.getY() - vy <= 0 && vy < 0 ) || (ball.getY() + vy >= (getWidth() - BALL_RADIUS*2) && vy>0)) {
			vy = -vy;
		}
	}