create a login page which allow user to register with his facebook account

I have to create开发者_开发知识库 an app in android which will allow users to login in with their facebook account....if his mobile is connected to the internet.

Could someone give me a hint/example of how could that be done? Thank you

Try following this tutorial here it will take you through step by step on how to set up for application to use facebook. It also goes through how to setup the keys etc. Hope this helps!