Blackberry - fields layout animation

It's easy to show some animation within one field - BitmapField or Screen:
[Blackberry - background image/animation RIM OS 4.5.0][1]

But what if you need to move fields, not just images?

May be used:

• game workflow functionality, like chess, puzzle etc
• application user-defined layout, like in Google gadgets
• enhanced GUI animation effects

So, I'd like to exchange my expirience in this task, on the other hand, I'd like to know about any others possibilities and suggestions.

This effect may be easily achived with custom layout:

class AnimatedManager extends Manager {
    int ANIMATION_NONE = 0;
    int ANIMATION_CROSS_FLY = 1;
    boolean mAnimationStart = false;
    Bitmap mBmpBNormal = Bitmap.getBitmapResource("blue_normal.png");
    Bitmap mBmpBFocused = Bitmap.getBitmapResource("blue_focused.png");
    Bitmap mBmpRNormal = Bitmap.getBitmapResource("red_normal.png");
    Bitmap mBmpRFocused = Bitmap.getBitmapResource("red_focused.png");
    Bitmap mBmpYNormal = Bitmap.getBitmapResource("yellow_normal.png");
    Bitmap mBmpYFocused = Bitmap.getBitmapResource("yellow_focused.png");
    Bitmap mBmpGNormal = Bitmap.getBitmapResource("green_normal.png");
    Bitmap mBmpGFocused = Bitmap.getBitmapResource("green_focused.png");
    int[] width = null;
    int[] height = null;
    int[] xPos = null;
    int[] yPos = null;
    BitmapButtonField mBButton = new BitmapButtonField(mBmpBNormal,
            mBmpBFocused);
    BitmapButtonField mRButton = new BitmapButtonField(mBmpRNormal,
            mBmpRFocused);
    BitmapButtonField mYButton = new BitmapButtonField(mBmpYNormal,
            mBmpYFocused);
    BitmapButtonField mGButton = new BitmapButtonField(mBmpGNormal,
            mBmpGFocused);

    public AnimatedManager() {
        super(USE_ALL_HEIGHT | USE_ALL_WIDTH);
        add(mBButton);
        add(mRButton);
        add(mYButton);
        add(mGButton);
        width = new int[] { mBButton.getPreferredWidth(),
                mRButton.getPreferredWidth(), 
                mYButton.getPreferredWidth(),
                mGButton.getPreferredWidth() };

        height = new int[] { mBButton.getPreferredHeight(),
                mRButton.getPreferredHeight(),
                mYButton.getPreferredHeight(),
                mGButton.getPreferredHeight() };

        xPos = new int[] { 0, getPreferredWidth() - width[1], 0,
                getPreferredWidth() - width[3] };
        yPos = new int[] { 0, 0, getPreferredHeight() - height[2],
                getPreferredHeight() - height[3] };

        Timer timer = new Timer();
        timer.schedule(mAnimationTask, 0, 100);
    }

    TimerTask mAnimationTask = new TimerTask() {
        public void run() {
            UiApplication.getUiApplication().invokeLater(new Runnable() {
                public void run() {
                    updateLayout();
                };
            });
        };
    };

    MenuItem mAnimationMenuItem = new MenuItem("Start", 0, 0) {
        public void run() {
            mAnimationStart = true;
        };
    };

    protected void makeMenu(Menu menu, int instance) {
        super.makeMenu(menu, instance);
        menu.add(mAnimationMenuItem);
    }

    public int getPreferredHeight() {
        return Display.getHeight();
    }

    public int getPreferredWidth() {
        return Display.getWidth();
    }

    protected void sublayout(int width, int height) {
        width = getPreferredWidth();
        height = getPreferredHeight();

        if (getFieldCount() > 3) {
            Field first = getField(0);
            Field second = getField(1);
            Field third = getField(2);
            Field fourth = getField(3);

            layoutChild(first, this.width[0], this.height[0]);
            layoutChild(second, this.width[1], this.height[1]);
            layoutChild(third, this.width[2], this.height[2]);
            layoutChild(fourth, this.width[3], this.height[3]);

            if (mAnimationStart) {
                boolean anim1 = performLayoutAnimation(0,
                        width - this.width[0], 
                        height - this.height[0]);
                boolean anim2 = performLayoutAnimation(1, 0, 
                        height - this.height[1]);
                boolean anim3 = performLayoutAnimation(2,
                        width - this.width[2], 0);
                boolean anim4 = performLayoutAnimation(3, 0, 0);
                mAnimationStart = anim1 || anim2 || anim3 || anim4;
            }
            setPositionChild(first, xPos[0], yPos[0]);
            setPositionChild(second, xPos[1], yPos[1]);
            setPositionChild(third, xPos[2], yPos[2]);
            setPositionChild(fourth, xPos[3], yPos[3]);

        }

        setExtent(width, height);
    }

    boolean performLayoutAnimation(int fieldIndex, int x, int y) {

        boolean result = false;
        if (xPos[fieldIndex] > x) {
            xPos[fieldIndex] -= 2;
            result = true;
        } else if (xPos[fieldIndex] < x) {
            xPos[fieldIndex] += 2;
            result = true;
        }

        if (yPos[fieldIndex] > y) {
            yPos[fieldIndex] -= 1;
            result = true;
        } else if (yPos[fieldIndex] < y) {
            yPos[fieldIndex] += 1;
            result = true;
        }
        return result;
    }
}

BitmapButtonField class I've used:

class BitmapButtonField extends ButtonField {
    Bitmap mNormal;
    Bitmap mFocused;

    int mWidth;
    int mHeight;

    public BitmapButtonField(Bitmap normal, Bitmap focused) {
        super(CONSUME_CLICK);
        mNormal = normal;
        mFocused = focused;
        mWidth = mNormal.getWidth();
        mHeight = mNormal.getHeight();
        setMargin(0, 0, 0, 0);
        setPadding(0, 0, 0, 0);
        setBorder(BorderFactory.createSimpleBorder(new XYEdges(0, 0, 0, 0)));
        setBorder(VISUAL_STATE_ACTIVE, BorderFactory
                .createSimpleBorder(new XYEdges(0, 0, 0, 0)));
    }

    protected void paint(Graphics graphics) {
        Bitmap bitmap = null;
        switch (getVisualState()) {
        case VISUAL_STATE_NORMAL:
            bitmap = mNormal;
            break;
        case VISUAL_STATE_FOCUS:
            bitmap = mFocused;
            break;
        case VISUAL_STATE_ACTIVE:
            bitmap = mFocused;
            break;
        default:
            bitmap = mNormal;
        }
        graphics.drawBitmap(0, 0, bitmap.getWidth(), bitmap.getHeight(),
                bitmap, 0, 0);
    }

    public int getPreferredWidth() {
        return mWidth;
    }

    public int getPreferredHeight() {
        return mHeight;
    }

    protected void layout(int width, int height) {
        setExtent(mWidth, mHeight);
    }

    protected void applyTheme(Graphics arg0, boolean arg1) {

    }
}