Saving Data on Android

14
Chapter 14: Real/me 
Database Offline 
Capabili/es
By Dean Djermanović
So far, you've created an app that enables you to save posts to the database and read 
the posts from the database. The next step is to implement offline support. If you 
turn off your internet connection now and run your app, you'd see an empty screen. 
That is because your app can't fetch the data from the database without an internet 
connection.
One of the most important features of Realtime database is its offline capabilities. If 
you were creating your own backend system, you would need to persist the data by 
yourself. Firebase handles that for you, and it enables your app to work properly even 
when the user loses network connection. In this chapter, you'll learn how exactly it 
does that, and you'll add offline support to your app so that you could see posts on 
the screen and even add posts while you are offline.
Note
: If you skipped previous chapters, you need to setup Firebase in order to 
follow along. Do the following steps:
1. Create a project in the Firebase console.
2. Enable Google sign-in.
3. Set security rules to the test mode to allow everyone