Hey guys, still new to RX, when I try to use observables to get result from firestore

override fun loadDrillTypes(): Observable<ArrayList<DrillsType>> {

        val list = ArrayList<DrillsType>()

        firebaseFirestore.collection("drilltypes")
            .get()
            .addOnSuccessListener { documents ->
                for (document in documents) {
                    val doc = document.toObject(DrillsType::class.java)
                    list.add(doc)
                }
            }
            .addOnFailureListener { exception ->
                Log.w("TAG", "Error getting documents: ", exception)
            }
        return Observable.just(list)   // delay(2, TimeUnit.SECONDS)
    }

I get an empty ArrayList

compositeDisposable += repository.loadDrillTypes()
            .subscribeWith(object : DisposableObserver<ArrayList<DrillsType>>() {

            override fun onError(e: Throwable) {
                //if some error happens in our data layer our app will not crash, we will
                // get error here
            }

            override fun onNext(data: ArrayList<DrillsType>) {
                Log.d("TAG", data.toString())
            }

            override fun onComplete() {
                Log.d("TAG", "COMPLETE")
            }
        })
    }

But if i add the delay(2, seconds) then I get the normal result that I need... I am 100% sure there is a way around this without having it to be delayed. Or is the delay a standard practice?

Just

immediately fires the list and does not wait for the firestore to finish. OnSuccess/onFaliure is a callback from firestore. It doesn't block the execution of the function

Thanks. But I'd like to stay within rxkotlin library. I'll look into emiting the data somehow or something along those lines

so just to clarify RXFirebase is just a wrapper library around FIrebase. You can still use RxKotlin 🙂 if you want to implement it manually I would suggest to do something like the following:

Single.create { emitter -> 
val storageTask = firebaseFirestore.collection("drilltypes")
            .get()
            .addOnSuccessListener { documents ->
                val success = documents.map { document.toObject(DrillsType::class.java) }
                emitter.onSuccess(success)
            }
            .addOnFailureListener { exception ->
                if (emitter.isDisposed().not())
                    emitter.onError(exception)
                Log.w("TAG", "Error getting documents: ", exception)
            }

           emitter.setCancellable{ 
               storageTask.cancel()
           }
}

Thanks @kioba, i got the gist of it. I was searching for something like this!

let me know if you need anything else 👍