The MainActivity is a Login/Signup screen. After Login is successful the app pulls all the users from the server and opens a new Activity with a ListView which lists all the
usernames. At the top-right of the screen, in the overflow options menu we have two options: to Share a picture and/or to Sign Out. Tapping a username from the ListView opens a new Activity which shows all the user posts.
There are many functionalities missing but this could be a very good starting point for a social media app.
For the backend I used Parse Server which is an open source Backend-as-a-Service(BaaS) framework initially developed by Facebook and an AWS EC2 instance.
