Flutter: Shows some Firestore Collection with a StreamBuilder from an authenticated Firebase Auth User

Question

My app has a collection of cards and I need to add some car to the favorites list, and I would like that each user has its own favorites collection.

So I did the classic StreamBuilder sample to show some list on Flutter:

StreamBuilder<QuerySnapshot>(
    stream: getCars()

If the getCars() function is like this, everything is ok:

getCars() {
   return Firestore.instance
    .collection("users")
    .document("oT646MvXXXXXXXXXXXjlN8L1V2")
    .collection("cars").snapshots();

}

Let's say that "oT646MvXXXXXXXXXXXjlN8L1V2" is the FirebaseUser uid.

But how can I read FirebaseUser uid dinamically to return the collection?

I tried this code but it didn't work, since it returns a Future:

getCarsError() async { FirebaseUser fUser = await FirebaseAuth.instance.currentUser();

return Firestore.instance
    .collection("users")
    .document(fUser.uid)
    .collection("cars").snapshots();

}

How can I acompplish that?

thank you

@KENdi Can you please make sure to fix all the tags? This question is about Firestore and not the realtime database. — André Kool

Ferdi Ferdi · Accepted Answer · 2019-03-11T13:22:23

Okay, the idea is to create a stream (I use the rxDart library but you can make it without)

BehaviorSubject<Car> _carController = BehaviorSubject<Car>();
Function(Car) get pushCar => _carController.sink.add;
Stream<Car> get streamCar => _carController ;
...
StreamBuilder<Car>(
    stream: streamCar

Then in your async function:

void getCars() async{
   FirebaseUser fUser = await FirebaseAuth.instance.currentUser();
   Firestore.instance
    .collection("users")
    .document(fUser.uid)
    .collection("cars").getDocuments().then((querySnapshot){
      for (document in querySnapshot.documents){
        pushCar(Car.fromJson(document.data));                //Deserialize your car here
    }).catchError((e)=>print(e));                            //Do what you want to handle error
}

So you push asynchronously your car into your stream, and you just get the stream<Car>and print what you have to :)

Hope it's help !!

Flutter: Shows some Firestore Collection with a StreamBuilder from an authenticated Firebase Auth User

1 Answers