Saving Data on Android

18
Chapter 18: Reading Data 
from Cloud Firestore
By Dean Djermanović
In the previous chapter, you learned how to write data to the Firestore, and how to 
update or delete data from Firestore by implementing that functionality in the 
WhatsUp
 app. You also became familiar with the Firebase console and learned how 
to use it for managing data.
In this chapter, you'll continue working on your app. Since now you still don't have 
any data on the home screen when you run the app, you'll focus on implementing 
reading logic. In the process, you'll learn how to read data from the Firestore, how to 
listen for updates in real-time, and how queries work.
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