Question

i have a program that create the circle that move to random position with multithread, each thread will handle each circle movement. i know how to move a image but not a shape object.

g2d.draw(s.circle);

this line only paint the circle with spawn x y.

i’ve tried add
s.circle.getBounds().setLocation(s.x, s.y);
before
g2d.draw(s.circle);
but no effect

public void paint(Graphics g) {
    if (draw == true) {


        super.paint(g);
        Graphics2D g2d = (Graphics2D)g;

            for (Star s : this.items) {
                //g2d.drawImage(s.starImage, s.x, s.y, this);

                g2d.draw(s.circle);

            }

        Toolkit.getDefaultToolkit().sync();
        g.dispose();

    }
}

public void run() {

    //if (!items.isEmpty()) {
        while(true){
            try {
                for (Star s : this.items) {
                    s.move();
                }
                repaint();

                Thread.sleep(50);
            } catch (InterruptedException ex) {
                Logger.getLogger(Board.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    //}
}

Answer 1

You will have to

1) draw the circle
2) wait for some short interval (eg, 100ms)
3) REDRAW the same circle - This time with the background colour, so that it has the effect of erasing the shape.
4) draw the circle at the new location.
5) repeat.

Atleast the above worked for me when I was doing Java/2D – sorry for not posting the actual code, as it was long ago – but I’m sure you’ll figure it out 🙂