Blackberry -- Listfield with transparent rows

I have a screen with a background image being rendered like so:

     bg = new VerticalFieldManager(
            VerticalFieldManager.USE_ALL_WIDTH |
            VerticalFieldManager.USE_ALL_HEIGHT |
            VerticalFieldManager.NO_HORIZONTAL_SCROLLBAR |
            VerticalFieldManager.NO_VERTICAL_SCROLLBAR |
            VerticalFieldManager.NO_HORIZONTAL_SCROLL |
            VerticalFieldManager.NO_VERTICAL_SCROLL) {
        //Override the paint method to draw the background image.
        public void paint(Graphics graphics) {
            //Draw the background image and then call paint.
            graphics.drawBitmap(Graphics.getScreenWidth()/2 - bgBitmap.getWidth()/2,
                    Graphics.getScreenHeight()/2 - bgBitmap.getHeight()/2, 
                    bgBitmap.getWidth(), bgBitmap.getHeight(), bgBitmap, 0, 0);
            super.paint(graphics);
        }
    };
    add(bg);

Then I'm adding any fields for the screen to this manager. I have a ListField that I'd like to see the background through. When the screen is first rendered, all is well. I can see the image. As soon as I scroll down, select something and unselect it, the background disappears (turns white).

Do I need to do something special when drawing my list rows in order to make them truly transparent after the selection color is gone?

NOTE: I've found that this happens no matter what field is drawn on top of the background. It displays correctly until the selection color is drawn for a given focusable field and then you select something else. All the area that was filled with the selection color turns to the default white after unsel开发者_高级运维ecting it.

use invalidate() function within onfocus() and onunfocus() method.

For example if you use LabelField then use:

LabelField l=new LabelField("Hello",FOCUSABLE)
        {
            protected void onFocus(int direction) 
            {
                invalidate();
                super.onFocus(direction);
            }
            protected void onUnfocus() 
            {
                invalidate();
                super.onUnfocus();
            }
        };

I ended up overriding moveFocus() in my custom ListField.

    public int moveFocus(int amount, int status, int time) {
        invalidate(getSelectedIndex());
        return super.moveFocus(amount, status, time);
    }

Vivek's method works well for single fields outside of a ListField row though.