Android library that aims to hide Firebase Firestore listener implementation and expose only a Kotlin Flow of specified type. ;)
Works for ColletionReferences, Queries, and DocumentReferences.

Check the pre-requisites for Firebase Firestore and for Kotlin Flow on respective documentation.
Be familiar with Kotlin Coroutines.
Based on versions 24.0.0 and 1.4.1 of firebase-firestore-ktx and kotlinx-coroutines-play-services respectively

Lets start by adding a corresponding repository in your root build.gradle file.

allprojects {
    repositories {
        ..
        maven { url 'https://jitpack.io' }
    }
}

The next task is to add the dependency to your app build.gradle file.

dependencies {
    ..
    implementation 'com.github.horaciocome1:fireflow:$VERSION'
}

Now you ready to go.
You might want to sync your project first. ;)

val db = FirebaseFirestore.getInstance()
val ref = db.collection("posts")
ref.addSnapshotListener { snapshot, error ->
    if (error != null) {
        // handle
    } else if (snapshot != null) {
        val posts = snapshot.toObjects(Post::class.java)
        // set posts to UI
    }
}

val db = FirebaseFirestore.getInstance()
db.collection("posts").asFlow<Post>().collect { posts ->
    // set posts to UI
}

You can also specify a coroutineContext. Default is Dispatchers.IO.

val db = FirebaseFirestore.getInstance()
db.collection("posts").asFlow<Post>(coroutineContext = Dispatchers.Main).collect { posts ->
   // set posts to UI
}

You can also read documents as flows

val db = FirebaseFirestore.getInstance()
db.collection("posts").document("1")
    .asFlow<Post>().collect { post ->
        // set post to UI
    }

You can also serve as livedata (if you are using Jetpack Lifecycle)

val db = FirebaseFirestore.getInstance()
db.collection("posts").document("1")
    .asFlow<Post>()
    .asLivedata()

You can also get the snapshot itself ("we never know ...")

val db = FirebaseFirestore.getInstance()
db.collection("posts").document("1")
    .snapshotAsFlow().collect { snapshot ->
        // handle
    }

There is no Java support.
For other things please open an Issue or reach me via [email protected]

Copyright 2021 Horácio Flávio Comé Júnior

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Firebase Firestore is a product from Google.
Kotlin is a product from Jetbrains.

We open to suggestions of any kind. Email me, open pull requests, etc.

Hope you development experience gets smootherrrrr.
If you want to see another utility please check my work on Recyclerview.
Simple RecyclerView Listener
Simple RecyclerView Adapter