Question

I am a Blackberry java developer. I am trying to develop a simple slot machine logic. I am new to animated graphics etc in blackberry. So, can anyone tell me how to design a simple slot machine where on pressing a button the images in 3 blocks must start rotating and after it stops the prizes will be displayed according to the pics. So can u plz help me with some samples or tutorials of how to do it…

Edit: I am developing it just as fun application that doesnt involve any money transactions. So, any Blackberry developers plz guide me how to achieve the task and to spin the three images on click of a button…

Answer 1

This is a simple example but you will have to deal with decoration, smooth rolling etc yourself.

Let’s say you have 6 images 70×70.
Simple BitmapField extension to paint current slot image, half of image above and half of image below:

class SlotField extends BitmapField {
    Bitmap bmp1 = Bitmap.getBitmapResource("img1.png");
    Bitmap bmp2 = Bitmap.getBitmapResource("img2.png");
    Bitmap bmp3 = Bitmap.getBitmapResource("img3.png");
    Bitmap bmp4 = Bitmap.getBitmapResource("img4.png");
    Bitmap bmp5 = Bitmap.getBitmapResource("img5.png");
    Bitmap bmp6 = Bitmap.getBitmapResource("img6.png");

    Bitmap[] bmps = new Bitmap[] { bmp1, bmp2, bmp3, bmp4, bmp5, bmp6 };

    int mPos = 0;

    public SlotField(int position) {
        mPos = position;
    }

    public int getBitmapHeight() {
        return bmp1.getHeight() * 2;
    }

    public int getBitmapWidth() {
        return bmp1.getWidth();
    }

    protected void layout(int width, int height) {
        setExtent(getBitmapWidth(), getBitmapHeight());
    }

    int getNextPos() {
        if (mPos == bmps.length - 1) {
            return 0;
        } else
            return mPos + 1;
    }

    int getPrevPos() {
        if (mPos == 0) {
            return bmps.length - 1;
        } else
            return mPos - 1;
    }

    protected void paint(Graphics g) {
        Bitmap hImg = bmps[getPrevPos()];
        Bitmap mImg = bmps[mPos];
        Bitmap lImg = bmps[getNextPos()];
        g.drawBitmap(0, 0, 70, 35, hImg, 0, 35);
        g.drawBitmap(0, 35, 70, 70, mImg, 0, 0);
        g.drawBitmap(0, 105, 70, 35, lImg, 0, 0);
    }
}

Now put these fields on screen and animate with timer:

class MainScr extends MainScreen {
    SlotField slot1 = new SlotField(0);
    SlotField slot2 = new SlotField(3);
    SlotField slot3 = new SlotField(5);
    boolean running = false;

    public MainScr() {
        HorizontalFieldManager hField = new HorizontalFieldManager();
        add(hField);

        hField.add(slot1);
        hField.add(slot2);
        hField.add(slot3);

        ButtonField btnRoll = new ButtonField("Roll");
        btnRoll.setChangeListener(new FieldChangeListener() {
            public void fieldChanged(Field field, int context) {
                if (!running)
                    rollSlots();
            }
        });

        add(btnRoll);
    }

    void rollSlots() {
        Timer timer = new Timer();
        final Random rnd = new Random();
        TimerTask ttask1 = new TimerTask() {
            int cycle = 0;

            public void run() {
                slot1.mPos = slot1.getNextPos();
                invalidate();
                cycle++;
                if (cycle >= 100+rnd.nextInt(6))
                    cancel();
            }
        };

        TimerTask ttask2 = new TimerTask() {
            int cycle = 0;

            public void run() {
                slot2.mPos = slot2.getNextPos();
                invalidate();
                cycle++;
                if (cycle >= 100+rnd.nextInt(6))
                    cancel();
            }
        };

        TimerTask ttask3 = new TimerTask() {
            int cycle = 0;

            public void run() {
                slot3.mPos = slot3.getNextPos();
                invalidate();
                cycle++;
                if (cycle >= 100+rnd.nextInt(6))
                    cancel();
            }
        };

        timer.schedule(ttask1, 0, 50);
        timer.schedule(ttask2, 200, 50);
        timer.schedule(ttask3, 400, 50);
    }
}

alt text http://img534.imageshack.us/img534/2172/slots.jpg

For UI functionality read

Blackberry User Interface Design – Customizable UI?

and

Blackberry – fields layout animation