Chapter 08 · Firebase Firestore
Subchapter 8.10
references/standard/android_sdk_usage.mdMarkdown5 KBView on GitHub
This guide walks you through using Cloud Firestore in your Android app using Kotlin.
Before adding dependencies in your app, make sure you enable the Firestore service in your Firebase Project using the Firebase CLI:
npx -y firebase-tools@latest init firestoreIn your module-level build.gradle.kts (usually app/build.gradle.kts), add
the dependency for Cloud Firestore:
dependencies {
// [AGENT] Fetch the latest available BoM version from https://firebase.google.com/support/release-notes/android before adding this
implementation(platform("com.google.firebase:firebase-bom:<latest_bom_version>"))
// Add the dependency for the Cloud Firestore library
// When using the BoM, you don't specify versions in Firebase library dependencies
implementation("com.google.firebase:firebase-firestore")
}In your Activity or Fragment, initialize the FirebaseFirestore instance:
import com.google.firebase.firestore.FirebaseFirestore
import com.google.firebase.firestore.ktx.firestore
import com.google.firebase.ktx.Firebase
class MainActivity : AppCompatActivity() {
private lateinit var db: FirebaseFirestore
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val db = Firebase.firestore
setContent {
MaterialTheme {
Text("Firestore initialized!")
}
}
}
}Initialize inside a ComponentActivity using setContent:
import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Text
import com.google.firebase.Firebase
import com.google.firebase.firestore.firestore
class MainActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val db = Firebase.firestore
setContent {
MaterialTheme {
Text("Firestore initialized!")
}
}
}
}Add a new document with a generated ID using add():
// Create a new user with a first and last name
val user = hashMapOf(
"first" to "Ada",
"last" to "Lovelace",
"born" to 1815
)
// Add a new document with a generated ID
db.collection("users")
.add(user)
.addOnSuccessListener { documentReference ->
Log.d(TAG, "DocumentSnapshot added with ID: ${documentReference.id}")
}
.addOnFailureListener { e ->
Log.w(TAG, "Error adding document", e)
}Or set a document with a specific ID using set():
val city = hashMapOf(
"name" to "Los Angeles",
"state" to "CA",
"country" to "USA"
)
db.collection("cities").document("LA")
.set(city)
.addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully written!") }
.addOnFailureListener { e -> Log.w(TAG, "Error writing document", e) }Read a single document using get():
val docRef = db.collection("cities").document("SF")
docRef.get()
.addOnSuccessListener { document ->
if (document != null && document.exists()) {
Log.d(TAG, "DocumentSnapshot data: ${document.data}")
} else {
Log.d(TAG, "No such document")
}
}
.addOnFailureListener { exception ->
Log.d(TAG, "get failed with ", exception)
}Read multiple documents using a query:
db.collection("cities")
.whereEqualTo("capital", true)
.get()
.addOnSuccessListener { documents ->
for (document in documents) {
Log.d(TAG, "${document.id} => ${document.data}")
}
}
.addOnFailureListener { exception ->
Log.w(TAG, "Error getting documents: ", exception)
}Update some fields of a document using update() without overwriting the entire
document:
val washingtonRef = db.collection("cities").document("DC")
// Set the "isCapital" field to true
washingtonRef
.update("capital", true)
.addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully updated!") }
.addOnFailureListener { e -> Log.w(TAG, "Error updating document", e) }Delete a document using delete():
db.collection("cities").document("DC")
.delete()
.addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully deleted!") }
.addOnFailureListener { e -> Log.w(TAG, "Error deleting document", e) }