RxSwift和MVVM：可觀察不執行沒有綁定

Question

我是RxSwift的新手，嘗試使用MVVM架構的應用程序。我有視圖模型：

class CategoriesViewModel { 

fileprivate let api: APIService 
fileprivate let database: DatabaseService 

let categories: Results<Category> 

// Input 
let actionRequest = PublishSubject<Void>() 

// Output 
let changeset: Observable<(AnyRealmCollection<Category>, RealmChangeset?)> 
let apiSuccess: Observable<Void> 
let apiFailure: Observable<Error> 

init(api: APIService, database: DatabaseService) { 
    self.api = api 
    self.database = database 

    categories = database.realm.objects(Category.self).sorted(byKeyPath: Category.KeyPath.name) 

    changeset = Observable.changeset(from: categories) 

    let requestResult = actionRequest 
     .flatMapLatest { [weak api] _ -> Observable<Event<[Category]>> in 
      guard let strongAPI = api else { 
       return Observable.empty() 
      } 

      let request = APIService.MappableRequest(Category.self, resource: .categories) 
      return strongAPI.mappedArrayObservable(from: request).materialize() 
     } 
     .shareReplayLatestWhileConnected() 

    apiSuccess = requestResult 
     .map { $0.element } 
     .filterNil() 
     .flatMapLatest { [weak database] newObjects -> Observable<Void> in 
      guard let strongDatabase = database else { 
       return Observable.empty() 
      } 

      return strongDatabase.updateObservable(with: newObjects) 
     } 

    apiFailure = requestResult 
     .map { $0.error } 
     .filterNil() 
} 

} 

，我必須在視圖控制器以下binginds：

viewModel.apiSuccess 
     .map { _ in false } 
     .bind(to: refreshControl.rx.isRefreshing) 
     .disposed(by: disposeBag) 

    viewModel.apiFailure 
     .map { _ in false } 
     .bind(to: refreshControl.rx.isRefreshing) 
     .disposed(by: disposeBag) 

但如果我評論的綁定，與數據庫更新部分停止執行。無論如何，我需要使其執行，而不必在視圖模型中使用處理袋。可能嗎？

和小附加的問題：我應該用在我的視圖模型代碼api/database和return Observable.empty()狀或弱強的舞蹈，我可以只使用unowned api/unowned database安全？

謝謝。

UPD：

功能在APIService回報觀察到：

func mappedArrayObservable<T>(from request: MappableRequest<T>) -> Observable<[T]> { 
    let jsonArray = SessionManager.jsonArrayObservable(with: request.urlRequest, isSecured: request.isSecured) 
    return jsonArray.mapResponse(on: mappingSheduler, { Mapper<T>().mapArray(JSONArray: $0) }) 
} 

Answer 1

工作也無法完成，除非有準備接受結果的用戶。

您的DatabaseService需要在其中包含一個dispose包並訂閱Observable<[Category]>。喜歡的東西：

class ProductionDatabase: DatabaseService { 

    var categoriesUpdated: Observable<Void> { return _categories } 

    func updateObservable(with categories: Observable<[Category]>) { 
     categories 
      .subscribe(onNext: { [weak self] categories in 
       // store categories an then 
       self?._categories.onNext() 
      }) 
      .disposed(by: bag) 
    } 

    private let _categories = PublishSubject<Void>() 
    private let bag = DisposeBag() 
} 

然後apiSuccess = database.categoriesUpdated和database.updateObservable(with: requestResult.map { $0.element }.filterNil())