In App - Custom Fields and Logic App

Hi Experts - quick question

i have added a custom field using Custom Fields and logic App. There is a requirement to pre-fill this field through Cloud BADI and grey out this (should not be editable). I was able accomplish the pre-fill part through cloud BADI. but can you please help on how to make it non-editable? am using the procurement purchase order item business context. field is added at PO line level.

thanks a lot for your inputs as always. this is a great forum to share ideas.

Thanks

Srini