Based on my experience, here is a step by step guide for implementing Facebook login in your app using Facebook SDK v4.0
With the advancement in technology research. New SDK’s are getting periodically released, while older ones get deprecated. This is the sole reason why, inspite of a lot many tutorials and blogs out there, I have decided to write yet another tutorial which serves the same purpose but with a major difference – This is based on my own experience as an Android developer and I’ve provided a detailed and updated description on how to implement FB login while using their latest SDK. Adding Facebook login in your apps is even simpler with the new SDK than with the last although the first time around, it can be hard, thanks to the lack of a proper updated guides/tutorials.
Be advised, this tutorial quite rudimentary and is intended for those who have a hard time following the official Facebook documentation.