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Thread: Java bouncing balls flickering

  1. #1
    Junior Member
    Join Date
    Apr 2013
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    Default Java bouncing balls flickering

    Hi all, I am very new to Java and need help with this code if possible. I am to create an applet that creates a number of balls derived from a HTML.They bounce of the bounds of the frame but do not bounce of each other!

    I think I have most of the code however this keeps Flickering any help appreciated! I am very new to Java and coding in general, threads are killing me!
    I have been at this for days so any help at all appreciated!

    import java.applet.*;
    import java.awt.*;
    import java.util.Random;
    class Ball {
        Graphics g;
        int x;
        int y;
        int xmove; // x movement
        int ymove; // y movement
        int radius;
        Color bColor;
        private final Random generator = new Random();
        public Ball(Color c,int width,int height) {
            x = generator.nextInt(width);
            y = generator.nextInt(height);
            // calculate random direction (and speed)
            xmove = generator.nextInt(5) + 1;
            ymove = generator.nextInt(5) + 1;
            radius = 10;
            bColor = c;
        }// end constructor Ball
        public void paint(Graphics graphik) {
            graphik.fillOval(x - radius, y - radius, 2 * radius, 2 * radius);
        }// end method paint
        public void moveBall(int width,int height) {
            if ((x - radius + xmove < 0) || (x + radius + xmove > width)) {
                xmove = -xmove;
            if ((y - radius + ymove < 0) || (y + radius + ymove > height)) {
                ymove = -ymove;
            // recalulate the x,y coordinates of the circle
            x += xmove;
            y += ymove;
        }// end method moveBall
    }// end class ball
    public class BallsBounce extends Applet implements Runnable {
        Thread th;
        int numBalls;
        Graphics graphic;
        Image img;
        Ball balls[];
        private Color Colors[] = {Color.GRAY, Color.BLUE, Color.ORANGE, Color.CYAN, Color.BLACK, Color.MAGENTA, Color.GREEN, Color.PINK, Color.YELLOW, Color.RED};
        int c = 0; // count the colors used
        public void init() {
            numBalls = Integer.parseInt(getParameter("balls"));
            img = createImage(getWidth(), getHeight());
            graphic = img.getGraphics();
            balls = new Ball[numBalls];
            for (int i = 0; i < numBalls; i++) {
                if (c >= 10) {
                    c = 0;
                }// end if
                balls[i] = new Ball(Colors[c],getWidth(), getHeight());
            }// end for
        }// end method init
        public void start() {
            if (th == null) {
                th = new Thread(this);
            }// end if
        }// end method start
        public void run() {
            while (true) {
                for (int j = 0; j < numBalls; j++) {
                    balls[j].moveBall(getWidth(), getHeight());
                }// end for
                try {
                }// end try
                catch (InterruptedException except) {
                }// end catch
            }// end while
        }// end method run
        public void paint(Graphics g) {
            //g.clearRect(0, 0, this.getWidth(), this.getHeight());
            graphic.clearRect(0, 0, this.getWidth(), this.getHeight());
            for (int k = 0; k < numBalls; k++) {
                g.drawImage(img, 10, 10, this);
            }// end for
        }// end method paint
    }// end class BallsBounce
    Last edited by Norm; April 21st, 2013 at 06:42 AM. Reason: Removed spaces from code tag

  2. #2
    Super Moderator jps's Avatar
    Join Date
    Jul 2012
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    Thanked 263 Times in 232 Posts

    Default Re: Java bouncing balls flickering

    Neat code formatting. Could use some comments.
    Do you have a question?

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