Gadgets affect the study habit of a student in many aspects. Using gadgets a student start becoming stupid, dependable, careless and do all his or her work with the help of gadgets. He also becomes drowsy and wants to do all his work in shortcut. This is a small answer of your question.
Make him useless
In this age of technology no part of life is deprived from the impact it has created on life pattern and so education is no exception. Education has undergone a revolutionary change with students being seen with laptops, tabs, and other gadgets.
Online education is the biggest proof of how education has been impacted with technology, no region in this world has remained aloof from this new form of education.