Re: Help needed to make this stop().

From:
Knute Johnson <nospam@rabbitbrush.frazmtn.com>
Newsgroups:
comp.lang.java.help
Date:
Thu, 24 Aug 2006 20:58:12 -0700
Message-ID:
<ryuHg.22126$C12.12372@newsfe06.phx>
bH wrote:

Hi All,
I have spent a lot of time looking at possibilites at making this stop,
nothing seems to make it happen. I have looked at the deprecated list
for stop. Still nothing makes it stop short of recompiling or getting
the
task manger to stop it. Your help is appreciated.

import java.awt.*;

public class FramedBouncingBalls
    extends Frame
    implements Runnable {

    Thread runner;
    Image buffer;
    Graphics gBuffer;
    Ball ball[];
    //how many balls?
    static final int MAX = 3;
    static final int WIDTH = 500;
    static final int HEIGHT = 400;
    private int offScreenBufferWidth;
    private int offScreenBufferHeight;

    public FramedBouncingBalls() {
        super("Bouncing Balls");
        setSize(WIDTH, HEIGHT);

        ball = new Ball[MAX];

        int w = WIDTH;
        int h = HEIGHT;

        //our balls have different start coordinates, increment values
        //(speed, direction) and colors

        ball[0] = new Ball(w, h, 50, 20, 1.5, 2.0, Color.blue);

        ball[1] = new Ball(w, h, 60, 100, 2.0, -3.0, Color.red);
        ball[2] = new Ball(w, h, 15, 70, -2.0, -2.5, Color.green);

        start();
        setVisible(true);
    }

    public void start() {
        if (runner == null) {
            runner = new Thread(this);
            runner.start();
        }
    }

    public void stop() {
        if (runner != null) {
           // runner.stop(); // the stop method of Thread has been
deprecated as it was unsafe


                 runner.interrupt();

            setVisible(false);
        }
    }

    public void run() {

        while (true)


            while (!Thread.interrupted()) {
     or
            while (!runner.isInterrupted()) {

            //Thread sleeps for 15 milliseconds here
            try {
                Thread.sleep(15);
            }
            catch (InterruptedException ie) {
            }

            //move our balls around
            for (int i = 0; i < MAX; i++) {
                ball[i].move();

            }
            repaint();
        }
    }

    public void update(Graphics g) {
        paint(g);
    }

    public void paint(Graphics g) {
        if (getWidth() != offScreenBufferWidth ||
            getHeight() != offScreenBufferHeight) {
            buffer = null;
            gBuffer = null;
            offScreenBufferWidth = getWidth();
            offScreenBufferHeight = getHeight();
        }
        if (buffer == null) {
            buffer = createImage(offScreenBufferWidth,
offScreenBufferHeight);
            gBuffer = buffer.getGraphics();
        }

        //draw a gray background and a grid of lines
        gBuffer.setColor(Color.gray);
        gBuffer.fillRect(0, 0, getWidth(), getHeight());

        gBuffer.setColor(Color.lightGray);

        //paint our balls
        for (int i = 0; i < MAX; i++) {
            ball[i].paint(gBuffer);

        }
        g.drawImage(buffer, 0, 0, this);
    }

    public static void main(String[] args) {
        new FramedBouncingBalls();
    }
}

class Ball {
    //the boundaries of the window and the diameter of our ball
    //we tell our balls the window size by constructor, so we can
    //change the applet's size easily
    int width, height;
    static final int diameter = 30;
    //coordinates and value of increment
    double x, y, xinc, yinc;
    Color color;
    Graphics g;

    //the constructor
    public Ball(int w, int h, int x, int y, double xinc, double yinc,
Color c) {
        width = w;
        height = h;
        this.x = x;
        this.y = y;
        this.xinc = xinc;
        this.yinc = yinc;
        color = c;
    }

    public void move() {
        x += xinc;
        y += yinc;

        //when the ball bumps against a boundary, it bounces off
        if (x < 0 || x > width - diameter) {
            xinc = -xinc;
            x += xinc;
        }

        if (y < 0 || y > height - diameter) {
            yinc = -yinc;
            y += yinc;
        }
    }

    public void paint(Graphics gr) {
        g = gr;
        g.setColor(color);
        //the coordinates in fillOval have to be int, so we cast
        //explicitly from double to int
        g.fillOval( (int) x, (int) y, diameter, diameter);
    }
}


--

Knute Johnson
email s/nospam/knute/

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