Question

I am having trouble with vertical scrolling on a blackberry app.
it works just fine on touch screens, but when scrolling using a track pad, it jumps from being at the top position to being at the bottom position.

Anyone had a similar problem? any idea what i could try?

Here is a snippet from my code. i have a static background image and the fields scroll on top of it:

vertical_main = new VerticalFieldManager(USE_ALL_WIDTH |NO_VERTICAL_SCROLL |USE_ALL_HEIGHT);
vertical_AllTags=new VerticalFieldManager(USE_ALL_WIDTH | VERTICAL_SCROLL);
// i then add all the fields to vertical_AllTags
vertical_main.add(vertical_AllTags);
vertical_main.invalidate();
add(vertical_main);

thanks in advance for your help

EDIT:
The suggestion of giving each field focus was correct. the only other part that needs to be done is when you override the onFocus method for a field, you need to call the super() function so that all the other normal parts of the onFocus method are still called:

protected void onFocus(int direction) {
    text_select=true;
    invalidate();
    super.onFocus(direction);
}

protected void onUnfocus() {
    text_select=false;
    invalidate();
    super.onUnfocus();
}

Thank you so much.

Answer 1

This is common issue in non touch devises for beginners.
if you want to scroll field by field there is two ways

1) you need to give the focus to all fields then it will come field by
field focus down

another way is means you dont need to focus on each and every field

2)just add the NullField after your every field and give focus to all
NullFields then your trackball will bring your screen field by field