RxSwift track multiple observables activity - ios

Question

I have following code:
let categoriesRequest = APIService.MappableRequest(Category.self, resource: .categories)
let categoriesRequestResult = api.subscribeArrayRequest(categoriesRequest, from: actionRequest, disposedBy: disposeBag)
let newCategories = categoriesRequestResult
.map { $0.element }
.filterNil()
let categoriesUpdateData = DatabaseService.UpdateData(newObjectsObservable: newCategories)
let categoriesDatabaseResult = database.subscribeUpdates(from: categoriesUpdateData, disposedBy: disposeBag)
let latestTopicsRequest = APIService.MappableRequest(Topic.self, resource: .latestTopics)
let latestTopicsRequestResult = api.subscribeArrayRequest(latestTopicsRequest, from: actionRequest, disposedBy: disposeBag)
let newLastTopics = latestTopicsRequestResult
.map { $0.element }
.filterNil()
let latestTopicsUpdateData = DatabaseService.UpdateData(newObjectsObservable: newLastTopics)
let latestTopicsDatabaseResult = database.subscribeUpdates(from: latestTopicsUpdateData, disposedBy: disposeBag)
There are two requests that starts from the same publish subject actionRequest, and two database updates after these requests.
I need something like isActive, bool value which will return true if any of api/database task is in progress. Is it possible? I saw ActivityIndicator in RxSwift examples, but I don't know is it possible to use it in my case.
Code from api/database if needed:
// API
func subscribeArrayRequest<T>(_ request: MappableRequest<T>,
from triggerObservable: Observable<Void>,
disposedBy disposeBag: DisposeBag) -> Observable<Event<[T]>> {
let result = ReplaySubject<Event<[T]>>.create(bufferSize: 1)
triggerObservable
.flatMapLatest {
SessionManager
.jsonArrayObservable(with: request.urlRequest, isSecured: request.isSecured)
.mapResponse(on: APIService.mappingSheduler) { Mapper<T>().mapArray(JSONArray: $0) }
.materialize()
}
.subscribe(onNext: { [weak result] event in
result?.onNext(event)
})
.disposed(by: disposeBag)
return result
}
// Database
func subscribeUpdates<N, P>(from data: UpdateData<N, P>, disposedBy disposeBag: DisposeBag) -> Observable<Void> {
let result = PublishSubject<Void>()
data.newObjectsObservable
.observeOn(DatabaseService.writingSheduler)
.subscribe(onNext: { [weak result] newObjects in
// update db
DispatchQueue.main.async {
result?.onNext(())
}
})
.disposed(by: disposeBag)
return result
}
Thanks.

Answer 1

Found following solution: pass ActivityIndicator instance to services methods and use it like this:
func bindArrayRequest<T>(_ request: MappableRequest<T>,
from triggerObservable: Observable<Void>,
trackedBy indicator: RxActivityIndicator,
disposedBy disposeBag: DisposeBag) -> Observable<Event<[T]>> {
let result = ReplaySubject<Event<[T]>>.create(bufferSize: 1)
triggerObservable
.flatMapLatest {
SessionManager
.jsonArrayObservable(with: request.urlRequest, isSecured: request.isSecured)
.mapResponse(on: APIService.mappingSheduler) { Mapper<T>().mapArray(JSONArray: $0) }
.materialize()
.trackActivity(indicator)
}
.bind(to: result)
.disposed(by: disposeBag)
return result
}
Also wrap database update logic into observable and use it with .trackActivity(indicator) into flatMapLatest like in api.
Then use api/database methods like this:
let indicator = RxActivityIndicator()
isUpdatingData = indicator.asObservable() // needed bool observable
let categoriesRequest = APIService.MappableRequest(Category.self, resource: .categories)
let categoriesRequestResult =
api.bindArrayRequest(categoriesRequest,
from: actionRequest,
trackedBy: indicator,
disposedBy: disposeBag)
let newCategories = categoriesRequestResult
.map { $0.element }
.filterNil()
let categoriesUpdateData = DatabaseService.UpdateData(newObjectsObservable: newCategories)
let categoriesDatabaseResult =
database.bindUpdates(from: categoriesUpdateData,
trackedBy: indicator,
disposedBy: disposeBag)
let latestTopicsRequest = APIService.MappableRequest(Topic.self, resource: .latestTopics)
let latestTopicsRequestResult =
api.bindArrayRequest(latestTopicsRequest,
from: actionRequest,
trackedBy: indicator,
disposedBy: disposeBag)
let newLastTopics = latestTopicsRequestResult
.map { $0.element }
.filterNil()
let latestTopicsUpdateData = DatabaseService.UpdateData(newObjectsObservable: newLastTopics)
let latestTopicsDatabaseResult =
database.bindUpdates(from: latestTopicsUpdateData,
trackedBy: indicator,
disposedBy: disposeBag)
isUpdatingData observable is what I needed.