Android MVVM 应用架构：如何将 FirebaseFirestore 设置为存储库

Question

I want to create a app with the new architecture components and i already set up the views and the ViewModel. At the moment my app performs all Firestore queries in the ViewModel and it works to some extent. Google recommends that you should provide a Repository that caches some data and decides whether to fetch new data. This makes perfectly sense for my application since a have several Fragments nested in my MainActivity and lots of other activites.

I decided to implement the repository and created a Kotlin Object (Singleton) for my repository. As a consequence i got the warning that i should not store a FirebaseFirestore instance in it because it contains a Context field (i need an instance to assign snapshotListeners).

Do not place Android context classes in static fields; this is a memory leak (and also breaks Instant Run)

I completely understand this warning but i wonder how i should implement the Repository pattern with Firebase in my app without being in danger of causing a memory leak ? Since Firebase and the new Architecure Components/Guidlines are both from Google i assume there are designed to work together but after doing some research i wasn't able to figure it out.

Does anyone know an effective way to implement a repository with Firebase snapshotListeners?

Answer 1

It's been a while since I asked this question. Meanwhile, I have found a great way to solve this problem. The best way is to make use of the repository pattern and Dependency Injection. That means you have a class with a private field firebaseFirestore that implements an interface that defines all database operations ( RemoteRepository in my case). The class itself is provided as a Singelton via Dependency Injection.

class FirebaseRepository : RemoteRepository {
   private val firebaseFirestore = FirebaseFirestore.getInstance()

   override suspend fun saveSomething(...) {
     ...
   }

   override suspend fun getSomething(id: String) : T {
     return ...
   }


}