I had created the screen layout by positioning the each component using the sublayout and tell the relative X, Y positions.
The problem is that when selecting a choice from the ObjectChoiceField or when adding a new text field programatically the whole layout draws again which causes the Scrollview jumps to the top from where the user previously interacted, causing pain to him.
Is it a problem to use sublayout for positioning? If so how can I create a complex layout in BlackBerry without sublayout?
You haven't posted code, so it's a bit difficult to pinpoint the problem. It sounds like your vertical scroll position is going to 0 whenever you modify the set of fields contained by the VFM. You can read the current scroll position before modifying the child fields, and then explicitly set it after doing your layout logic.