Rx in the real world. 1 Rob Ciolli

Transcription

1 Rx in the real world 1 Rob Ciolli

2 2 Rob Ciolli

3 3 Rob Ciolli

4 The App 4 Rob Ciolli

5 Quick architecture overview 5 Rob Ciolli

6 MV - WTF 6 Rob Ciolli

7 Model Simple, immutable data struct returned from DB or APIs 7 Rob Ciolli

8 View UI layout as defined in storyboard file 8 Rob Ciolli

9 Controller Regular Cocoa ViewController protocol ViewControllerProtocol: class {... associatedtype ViewModelType func recieve(viewmodel: ViewModelType) 9 Rob Ciolli

10 Presenter import UIKit protocol PresenterProtocol { associatedtype ViewControllerType: UIViewController func makeviewcontroller() -> ViewControllerType 10 Rob Ciolli

11 ViewModel protocol ViewModelDelegateProtocol { protocol ViewModelProtocol { associatedtype DelegateType //: ViewModelDelegateProtocol var delegate: DelegateType { get init(delegate: DelegateType) class BaseViewModel<T> : ViewModelProtocol { let delegate: T required init(delegate: T) { self.delegate = delegate 11 Rob Ciolli

12 Example 1 Beer Detail Page 12 Rob Ciolli

13 Beer Model struct Beer { let id: Int let name: String let style: String let brewry: String let abv: Double let ibu: Double let description: String let image: String 13 Rob Ciolli

14 Observable next complete error 14 Rob Ciolli

15 Observer 'Listens' to an Observable implements onnext, oncompleted, onerror subscribing or binding returns a Disposable DisposeBag pattern 15 Rob Ciolli

16 Observable example let observable = Observable<String>.create { observer in o.onnext("beer") o.onnext("is") o.onnext("good") o.oncompleted() return Disposables.create() 16 Rob Ciolli

17 Observer example let disposebag = DisposeBag() observable.subscribe( onnext: { s in print(s), onerror: { _ in print("wtf"), oncompleted: { _ in print("done") ).disposed(by: disposebag) 17 Rob Ciolli

18 Mutating the streams Observable Operators Transform => Map & FlatMap... Filter => Filter / Debounce / Skip / Take Combine => Zip / CombineLatest Error Handling => Retry / Catch 18 Rob Ciolli

19 Data Layer import RxSwift protocol Datalayer { func requestallbeers() -> Observable<[Beer]> 19 Rob Ciolli

20 DetailPresenter struct DetailPresenter { let beer: Beer init(beer: Beer) { self.beer = beer extension DetailPresenter: PresenterProtocol {... extension DetailPresenter: DetailViewModelDelegateProtocol { 20 Rob Ciolli

21 DetailViewModel protocol DetailViewModelDelegateProtocol: ViewModelDelegateProtocol { var beer: Beer { get class DetailViewModel: BaseViewModel<DetailViewModelDelegateProtocol> { let name = Variable<String?>("")... required init(delegate: DetailViewModelDelegateProtocol) { super.init(delegate: delegate) name.value = beer.name Rob Ciolli

22 Map 22 Rob Ciolli

23 DetailViewController class DetailViewController: UIViewController, ViewControllerProtocol {... let disposebag = weak var namelabel: weak var imageview: UIImageView! override func viewdidload() { super.viewdidload() viewmodel.name.asobservable().bindto(namelabel.rx.text).disposed(by: disposebag) viewmodel.image.asobservable().map { UIImage(named: $0)!.bindTo(imageView.rx.image).disposed(by: disposebag) 23 Rob Ciolli

24 Show me the code Example 1 - Beer Detail Page 24 Rob Ciolli

25 ! " Binding is too verbose Only displays one piece of data Not really reactive 25 Rob Ciolli

26 Example 1b Beer Detail Page (again...) heaps more reactive 26 Rob Ciolli

27 Binding 27 Rob Ciolli

28 what if... viewmodel.name.asobservable().bindto(namelabel.rx.text) looked like namelabel.rx.text <- viewmodel.name 28 Rob Ciolli

29 ... and you could add all disposables to disposebag in one call... disposebag.dispose([ namelabel.rx.text <- viewmodel.name, stylelabel.rx.text <- viewmodel.style, brewrylabel.rx.text <- viewmodel.brewry, ]) 29 Rob Ciolli

30 <- operator infix operator <- func <- <T>(property: ControlProperty<T>, variable: Variable<T>) -> Disposable { return variable.asobservable().bind(to: property) 30 Rob Ciolli

31 DisposeBag extension DisposeBag { func dispose(_ disposables: [Disposable]) { disposables.foreach { [unowned self] disposable in self.insert(disposable) 31 Rob Ciolli

32 ViewModel Requirements Page through [Beer] protocol DetailViewModelDelegateProtocol: ViewModelDelegateProtocol { var beers: Observable<[Beer]> { get Rob Ciolli

33 ViewModel Requirements React to Next/Prev let next = Variable<()>() let index: Variable<Int>... next.asobservable().subscribe(onnext: onnext)... private func onnext() { index.value += 1 33 Rob Ciolli

34 Combine Latest 34 Rob Ciolli

35 ViewModel Requirements Be heaps more reactive Observable.combineLatest(delegate.beers, index.asobservable(), resultselector: selectbeer) 35 Rob Ciolli

36 ViewModel Requirements Control enabled state of UIButton extension UIButton { var rx_driveenable: AnyObserver<Bool> { return UIBindingObserver(UIElement: self) { button, enabled in button.isuserinteractionenabled = enabled.asobserver() 36 Rob Ciolli

37 Show me the code (... and tests) Example 1b - Beer Detail Page 37 Rob Ciolli

38 Example 2 Sign in Page capture user input validate input call api and handle response 38 Rob Ciolli

39 Sign in ViewModel initialise protocol SigninViewModelDelegateProtocol: ViewModelDelegateProtocol { func signin(username: String, password: String) -> Observable<Void> class SigninViewModel: BaseViewModel<SigninViewModelDelegateProtocol> {... let username = Variable<String?>(nil) let password = Variable<String?>(nil) let signintapped = Variable<()>() let error = Variable<String?>(nil) let signedin = Variable<()>() 39 Rob Ciolli

40 Sign in ViewModel call api signintapped.asobservable().subscribe(onnext: signin).disposed(by: disposebag) private func signin() { guard let username = username.value, let password = password.value else { return delegate.signin(username: username, password: password).subscribe(onnext: onsignedin, onerror: onsigninerror).disposed(by: disposebag) private func onsignedin() { signedin.value = () private func onsigninerror(_: Error) { error.value = "Error signing in" 40 Rob Ciolli

41 Sign in ViewModel input validation var signinenabled: Observable<Bool> { return Observable.combineLatest(username.asObservable(), password.asobservable(), resultselector: inputisvalid) private func inputisvalid(username: String?, password:string?) -> Bool { guard let username = username, let password = password else { return false return!username.isempty &&!password.isempty 41 Rob Ciolli

42 Show me the code Example 2 - Beer Sign in 42 Rob Ciolli

43 Example 3 Beer ListView filter list show detail view 43 Rob Ciolli

44 List ViewModel let searchvariable = Variable<String?>("") let itemtapped = Variable<Int>(-1) required init(delegate: ListViewModelDelegateProtocol) {... itemtapped.asobservable().skip(1).subscribe(onnext: onitemtapped).disposed(by: disposebag) 44 Rob Ciolli

45 Filter 45 Rob Ciolli

46 List ViewModel func filteredbeers() -> Observable<[Beer]> { let search = searchvariable.asobservable() return Observable.combineLatest(delegate.beers, search, resultselector: filterbeers) private func filterbeers(beers: [Beer], search: String?) -> [Beer] { guard let search = search else { return beers return beers.filter { search.isempty $0.name.lowercased().contains(search.lowercased()) 46 Rob Ciolli

47 List ViewModel private func onitemtapped(index: Int) { delegate.showdetail(beers: filteredbeers(), index: index) 47 Rob Ciolli

48 List ViewController viewmodel.filteredbeers().debounce(0.3, scheduler: MainScheduler.instance).bind(to: tableview.rx.items( cellidentifier: "Cell", celltype: UITableViewCell.self), curriedargument: initialisecell) 48 Rob Ciolli

49 Show me the code Example 3 - Beer List 49 Rob Ciolli

50 Wash up single responsibility is good Rx makes us think about data flow infix operators and swift extensions are cool 50 Rob Ciolli

51 Resources http: /reactivex.io/ http: /rxmarbles.com/ https: /github.com/reactivex/rxswift 51 Rob Ciolli

52 Thank <- (, ) 52 Rob Ciolli