Saving Data on Android

Key points
• Firestore allows to 
read data once
 or to 
listen for data changes
 in real-time.
• To get the data once, you would need to use 
get
 method on the collection
Saving Data on Android
Chapter 18: Reading Data from Cloud Firestore
raywenderlich.com
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reference.
•
ListenerRegistration
 interface represents a Firestore subscription listener.
• You can call 
addSnapshotListener()
 on a collection reference to start listening 
for data changes at a specific location.
•
Queries
 are used to get only a 
subset
 of the documents within a collection.
• Cloud Firestore stores a copy of data that your app is using, locally, so that you can 
access the data, if the device goes offline.
• You can also use 
orderBy()
 and 
limit()
, on the collection reference, to get only 
specific documents from a collection.
•
Pagination
 allows you to split your database data into 
chunks
 so that you don't 
need to fetch all your data at once.
• To ensure good performance for every query, Firestore requires an index, when 
creating them.