Data driven view controllers

Originally posted here: https://speakerdeck.com/vmalakhovskiy/data-driven-view-controllers

Github link: https://github.com/vmalakhovskiy/data-driven-vc

Vitaly about his workshop:
"I will show how to unify/simplify view-presenter communication, using data-driven approauch. Of cource a bit about functional programming, code generation, comparison with other architectures and more."

This workshop was made for CocoaHeads Kyiv #14 which took place Oct 6 2018.

Transcript

1. data-driven view controllers Vitalii Malakhovskyi Vitalii Malakhovskyi, BetterMe 1
2. Vitalii Malakhovskyi, BetterMe 2
3. Plan » what is data driven view controllers? » basic examples » code » home work: github Vitalii Malakhovskyi, BetterMe 3
4. what is that, data-driven view controllers? Vitalii Malakhovskyi, BetterMe 4
5. simplest view data representation as possible Vitalii Malakhovskyi, BetterMe 5
6. struct/enum immutable! Vitalii Malakhovskyi, BetterMe 6
7. struct ViewData { let title: String let message: String } Vitalii Malakhovskyi, BetterMe 7
8. Doesn't know about » entities » managed objects » models » services » etc Vitalii Malakhovskyi, BetterMe 8
9. it's only about view Vitalii Malakhovskyi, BetterMe 9
10. May contain: » string, number, bool » struct, enum, array » nested » closure <- for output Vitalii Malakhovskyi, BetterMe 10
11. ()->() Vitalii Malakhovskyi, BetterMe 11
12. (Input)->() Vitalii Malakhovskyi, BetterMe 12
13. ((Input)->())? Vitalii Malakhovskyi, BetterMe 13
14. (Input)->(Output) Vitalii Malakhovskyi, BetterMe 14
15. (Input)-> throws () Vitalii Malakhovskyi, BetterMe 15
16. struct Props { let title: String let journeys: [ViewData.Journey] struct Journey { let name: String let description: String let image: UIImage let progress: String let isLocked: Bool let onSelect: () -> () } } Vitalii Malakhovskyi, BetterMe 16
17. struct Props { let title: String let journeys: [ViewData.Journey] struct Journey { let name: String let description: String let image: UIImage let progress: String let isLocked: Bool let onSelect: () -> () } } Vitalii Malakhovskyi, BetterMe 17
18. unidirectional Vitalii Malakhovskyi, BetterMe 18
19. once somthing changed everything gets updated Vitalii Malakhovskyi, BetterMe 19
20. main idea only valid state Vitalii Malakhovskyi, BetterMe 20
21. wrong struct Interface { let programs: [Program] let temperatures: [Temperature] let RPMs: [RPM] enum Program {} enum Temperature {} enum RPM {} } Vitalii Malakhovskyi, BetterMe 21
22. correct enum Interface { case handWash90Degree case wool30Degree case off } Vitalii Malakhovskyi, BetterMe 22
23. Vitalii Malakhovskyi, BetterMe 23
24. enum Props { case loading([Loading]) case error(title: String, message: String, onReload: () -> ()) case data([Data]) struct Data {} struct Loading {} } Vitalii Malakhovskyi, BetterMe 24
25. should not relay on previous data Vitalii Malakhovskyi, BetterMe 25
26. single source of update Vitalii Malakhovskyi, BetterMe 26
27. UIView/UIViewController Vitalii Malakhovskyi, BetterMe 27
28. func render(props: Props) { self.props = props view.setNeedsLayout() } func viewWillLayoutSubviews() { super.viewWillLayoutSubviews() /// redraw view state } Vitalii Malakhovskyi, BetterMe 28
29. EXAMPLE Vitalii Malakhovskyi, BetterMe 29
30. 1 Vitalii Malakhovskyi, BetterMe 30
31. Presenter <- View Vitalii Malakhovskyi, BetterMe 31
32. ViewData should be observable Vitalii Malakhovskyi, BetterMe 32
33. protocol ViewModel { var viewData: Property<ViewData> { get } } Vitalii Malakhovskyi, BetterMe 33
34. class ViewController: UIViewController { func viewDidLoad() { viewModel.viewData.producer.startWithValues { _ in view.setNeedsLayout() } } func viewWillLayoutSubviews() { switch viewModel.viewData.value { ... } } } Vitalii Malakhovskyi, BetterMe 34
35. how to achieve this? » reactive cocoa » rxswift » handmade observations » KVO Vitalii Malakhovskyi, BetterMe 35
36. 2 Vitalii Malakhovskyi, BetterMe 36
37. Presenter <-> View Vitalii Malakhovskyi, BetterMe 37
38. VIPER Vitalii Malakhovskyi, BetterMe 38
39. /// View -> Presenter protocol ViewOutput { func viewIsReady() } /// Presenter -> View protocol PresenterOutput: { func receiveUpdate(with data: ViewData) } Vitalii Malakhovskyi, BetterMe 39
40. space for bugs Vitalii Malakhovskyi, BetterMe 40
41. 3 Vitalii Malakhovskyi, BetterMe 41
42. Presenter -> View Vitalii Malakhovskyi, BetterMe 42
43. class ViewController: UIViewController { struct ViewData {} func render(viewData: ViewData) { self.viewData = viewData view.setNeedsLayout() } } struct Presenter { let render: (ViewData) -> () func handleNewAppState(...) // calls render } Vitalii Malakhovskyi, BetterMe 43
44. View has no dependencies Vitalii Malakhovskyi, BetterMe 44
45. UIKit owns UIViewController store owns presenter Vitalii Malakhovskyi, BetterMe 45
46. CODE! Vitalii Malakhovskyi, BetterMe 46
47. * simple input * input + validation * multistate screen * animation * MVVM vc DD MVVM * VIPER vc DD VIPER * MVC vc DD MVC Vitalii Malakhovskyi, BetterMe 47
48. GITHUB github.com/vmalakhovskiy/data-driven-vc Vitalii Malakhovskyi, BetterMe 48
49. THANKS! Vitalii Malakhovskyi, BetterMe 49
50. * Data-Driven View Controllers. Tips and Tricks * github * Redux Vitalii Malakhovskyi, BetterMe 50
51. Questions? Vitalii Malakhovskyi, BetterMe 51
52. purpleshirted Vitalii Malakhovskyi VitaliyMal vmalakhovskiy Vitalii Malakhovskyi, BetterMe 52