Cancel navigation at onInputProcessing

Question

Hello,
I have an editable table view with the standard prev/next buttons. When the user changes data I want to validate it before it is saved. This is easy for my own events.
If the user changes something and then clicks "prev" or "next", I can see this at onInputProcessing. I could do the necessary checks and I notice that "prev" or "next" was clicked, BUT I cannot cancel the navigation.
Of course I can cancel the navigation using Java Script on the button, but A) I did not create the button and B) the checks are quite complex and I'd prefer to do it in ABAP.
Is there a way to cancel navigation at onInputProcessing? Otherwise I'd have to create my own "prev" and "next" buttons, but this will look ugly.
Thank you
Roland

Answer 1

> To which page you are being navigated?
Like I said, the user clicked "next" on a tableView, so the BSP page stays the same, just with a new set of table lines. I don't want this to happen in certain cases though.
> What do you mean by cancel navigation?
see above, the table should not change to new lines
> Is it a standard application you are working on? or custom application?
a custom BSP application