Realm Centered Design

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1. yohei SUGIGAMI Realm Centered Design RxSwift+RxRealm w/ RealmNotification Sep. 29,

   2016 @ SanSan Realm meetup #19

2. Yohei SUGIGAMI ID susieyy TwitterˍGithub & Qiita

3. γΰτͰίίϩΦυϧ Launch iPhone3G iOS Developer since mid 2008

4. γΰτͰίίϩΦυϧ WWDC 2014 Swift Developer since Day1

5. γΰτͰίίϩΦυϧ Working in a Wantedly

6. Our issues in iOS development

7. Our issues in iOS development Complex

8. Our issues in iOS development State and data management Complex

9. Our issues in iOS development Asynchronous processing Complex

10. Our issues in iOS development Massive delegate pattern Complex https://developer.apple.com/library/content/documentation/General/Conceptual/DevPedia-CocoaCore/MVC.html

    Apple MVC Apple MVC

11. Reactive program paradigm Observable Asynchronous data streams Functional program paradigm

    No side effects function Immutable structure Higher-order functions Lambda expression, monads Asynchronous friendly Unidirectional Data Flow Single source of truth The approach avoids complicated to simplify Redux RxSwift Reactive Cocoa simplify

12. Hoping between RxSwift and ReSwift Redux Rx ??? w/ MVVM

    (RxSwift) (ReSwift) Unidirectional 
 Data Flow
13. None
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17. None

18. Approaching based on Rx with Realm Redux Rx Realm +

    w/ MVVM (RxSwift) (ReSwift) Unidirectional 
 Data Flow Unidirectional 
 Data Flow (RxRealm)

19. Realm Centered Design View ViewModel Model Rx ( Local state

    ) Store ( App state ) Rx w/ MVVM

20. Unidirectional Data Flow Transaction ( atomic ) Notification Subscribe Realm

    Centered Design https://realm.io/news/unidirectional-data-flow-in-swift/

21. Launch iPhone3G iOS Developer since mid 2008 Key technologies Realm

    Notification RxRealm RxSwift w/ MVVM

22. Launch iPhone3G iOS Developer since mid 2008 Realm Notification Notifications

    section https://realm.io/docs/swift/latest/#notifications Collection Notifications, since ver 0.98 https://realm.io/news/realm-objc-swift-0.98.0/ Fine-grained change notifications, since ver 0.99 https://realm.io/news/realm-objc-swift-0.99.0/

23. Launch iPhone3G iOS Developer since mid 2008 Do you know

    the Realm Notification?

24. Launch iPhone3G iOS Developer since mid 2008 You can be

    notified whenever a Realm, Results, List or LinkingObjects is updated by calling the addNotificationBlock method. a.k.a. Observe What Realm Notification

25. Launch iPhone3G iOS Developer since mid 2008 Realm Notifications Collection

    Notifications Fine-grained change Points

26. Launch iPhone3G iOS Developer since mid 2008 Realm instances send

    out notifications to other instances on other threads every time a write transaction is committed: Realm Notifications

27. Launch iPhone3G iOS Developer since mid 2008 Realm Notifications, e.g.

28. Launch iPhone3G iOS Developer since mid 2008 Collection Notifications Notified

    of updates to query results or to specific objects.

29. Launch iPhone3G iOS Developer since mid 2008 ( should keep

    a strong reference ) Collection Notifications, e.g.

30. Launch iPhone3G iOS Developer since mid 2008 Fine-grained level changing

    This change parameter describes including the indices of objects that have been inserted, deleted, or modified since the last notification.

31. Launch iPhone3G iOS Developer since mid 2008 notified indices with

    deltas Fine-grained change, e.g.

32. Launch iPhone3G iOS Developer since mid 2008 In the case

    of Core Data let notificationCenter = NSNotificationCenter.defaultCenter() notificationCenter.addObserver(self, selector: #selector(managedObjectContextDidChange:), name: NSManagedObjectContextObjectsDidChangeNotification,
 object: privateManagedObjectContext) Can not observe with filtering.

33. Launch iPhone3G iOS Developer since mid 2008 In the case

    of Core Data func managedObjectContextObjectsDidChange(notification: NSNotification) { guard let userInfo = notification.userInfo else { return } if let inserts = userInfo[NSInsertedObjectsKey] as? Set<NSManagedObject> where inserts.count > 0 { } if let updates = userInfo[NSUpdatedObjectsKey] as? Set<NSManagedObject> where updates.count > 0 { } if let deletes = userInfo[NSDeletedObjectsKey] as? Set<NSManagedObject> where deletes.count > 0 { } } Received changed objects, instead of changed indices

34. Launch iPhone3G iOS Developer since mid 2008 Notified timing When

    notifications can’t be delivered instantly, multiple write transactions may be coalesced into a single notification. t Tx COMMIT Tx COMMIT Tx COMMIT Tx COMMIT Tx COMMIT t Notice Notice Write Notification

35. Launch iPhone3G iOS Developer since mid 2008 It is also

    notified being monitored relation destination of the change of the Object. Observable relations ( linking objects )

36. Launch iPhone3G iOS Developer since mid 2008 Observable relations (

    linking objects ) UserObject name avatar_url registered deleted_at profile ProfileObject company position working_histories academy_records emails EmailObject email Observe Change Change Notified

37. Launch iPhone3G iOS Developer since mid 2008 Model View B

    View A Notification Notification WriteTx Absolutely separation logic and views Singleton PreFetch BackgroundFetch

38. Launch iPhone3G iOS Developer since mid 2008 View A View

    B Notification WriteTx Absolutely separation logic and views

39. e.g. WriteTx Notification Notification ➜ ➜

40. Launch iPhone3G iOS Developer since mid 2008 RxSwift RxRealm x

    meets https://github.com/RxSwiftCommunity/RxRealm

41. Launch iPhone3G iOS Developer since mid 2008 What RxRealm Rx

    wrapper for Realm's collection types.

42. Launch iPhone3G iOS Developer since mid 2008 Observing collections Adds

    to Results, List, LinkingObjects and AnyRealmCollection these methods: - asObservable() - asObservableArray() - asObservableChangeset() - asObservableArrayChangeset() returning an Observable<Array<T>, RealmChangeset?>

43. Launch iPhone3G iOS Developer since mid 2008 try! Realm().objects(ContactRealm) .asObservableChangeset()

    .subscribeNext { [weak self] results, changeset in guard let tableView = self?.tableView else { return } self?.results = results if let changeset = changeset { tableView.beginUpdates() tableView.insertRowsAtIndexPaths(…, withRowAnimation: .Automatic) tableView.deleteRowsAtIndexPaths(…, withRowAnimation: .Automatic) tableView.reloadRowsAtIndexPaths(…, withRowAnimation: .Automatic) tableView.endUpdates() } else { tableView.reloadData() } }.addDisposableTo(disposeBag) e.g.

44. - rx_add() - rx_delete() Write transactions // Simple Create [MessageRealm("hello"),

    MessageRealm("world")] .toObservable() .subscribe(Realm.rx_add()) // With API let request = API.Endpoint.MessagesRequest().request() Session.rx_response(request) .subscribe(Realm.rx_add())

45. B Launch iPhone3G iOS Developer since mid 2008 RxSwift MVVM

    Realm Centered Design RxRealm

46. Launch iPhone3G iOS Developer since mid 2008 View ViewModel View

    A Subscribe Holding - The state of a screen-specific (Requesting, etc) - The main data of a screen RxSwift w/ MVVM It is difficult to handle the screen cross-data. View B View C

47. Launch iPhone3G iOS Developer since mid 2008 View ViewModel Subscribe

    Singleton RxSwift w/ MVVM and Singleton Global ViewModel View A View B View C Holding - The state of a screen-specific (Requesting, etc) - The main data of a screen (Rx Variable) The state of cross over screens

48. Launch iPhone3G iOS Developer since mid 2008 View ViewModel Observable

    Store Subscribe The state of a screen-specific Singleton RxSwift+RxRealm w/ MVVM (RxRealm) View A View B View C (Rx Variable) The main data of screens The state of cross over screens

49. Conclusion Simple ( is not easy ) Complex

50. 5IBOL
    ZPV