Model-View-Intent

Andrdoid GDG Meetup 24th of Jannuary 2017

Transcript

1. MODEL-VIEW-INTENT Hannes Dorfmann
2. MVI MVP MVC MVVM MVC
3. MVI MVP MVC MVVM
4. WHAT IS A MODEL?
5. class PersonsPresenter extends Presenter<PersonsView> { public void load(){ getView().showLoading(true); // Displays a ProgressBar backend.loadPersons(new Callback(){ public void onSuccess(List<Person> persons){ getView().showPersons(persons); // Displays a list of Persons } public void onError(Throwable error){ getView().showError(error); // Displays a error message }); } }
6. class PersonsModel { private final boolean loading; private final List<Person> persons; private final Throwable error; public(boolean loading, List<Person> persons, Throwable error){ this.loading = loading; this.persons = persons; this.error = error; } // ... getters ... }
7. class PersonsPresenter extends Presenter<PersonsView> { public void load(){ getView().render( new PersonsModel(true, null, null) ); backend.loadPersons(new Callback(){ public void onSuccess(List<Person> persons){ getView().render( new PersonsModel(false, persons, null) ); } public void onError(Throwable error){ getView().render( new PersonsModel(false, null, error) ); } }); } }
8. MODEL-VIEW-INTENT
9. ANDRÉ MEDEIROS (STALTZ) cycle.js http://cycle.js.org
10. intent()
11. model( intent() )
12. view( model( intent() ) )
13. view( model( intent() ) )
16. public interface SearchView { Observable<String> searchIntent(); void render(SearchViewState viewState); }
17. class SearchViewState { Throwable error; boolean loading; List<Product> result; }
18. public class SearchFragment extends Fragment implements SearchView { ... @Override public Observable<String> searchIntent() { return RxSearchView.queryTextChanges(searchView) // Thanks Jake Wharton .filter(queryString -> queryString.length() > 3) .debounce(500, TimeUnit.MILLISECONDS); } }
19. public class SearchFragment extends Fragment implements SearchView { ... @Override public void render(SearchViewState viewState) { if (viewState.isLoading()) { renderLoading(); } else if (viewState.getResult() != null) { renderResult(viewState.getResult()); } else if (viewState.getError() != null) { renderError(); } else { throw new IllegalArgumentException("Don't know how to render viewState"); } } }
20. // Mosby 3.0 public class SearchPresenter extends MviBasePresenter<SearchView> { private final SearchInteractor searchInteractor; @Override protected void bindIntents() { Observable<SearchViewState> search = intent(SearchView::searchIntent) .flatMap(searchInteractor::search) subscribeViewState(search, SearchView::render); } }
21. public class SearchInteractor { SearchEngine searchEngine; // Makes http calls public Observable<SearchViewState> search(String searchString) { return searchEngine.searchFor(searchString) // Observable<List<Product>> .map(products -> new SearchViewState(false, products, null)) .startWith(new SearchViewState(true, null, null)) .onErrorReturn(error -> new SearchViewState(false, null, error)); } }
22. public class SearchInteractor { SearchEngine searchEngine; // Makes http calls public Observable<SearchViewState> search(String searchString) { return searchEngine.searchFor(searchString) // Observable<List<Product>> .map(products -> new SearchViewState(false, products, null)) .startWith(new SearchViewState(true, null, null)) .onErrorReturn(error -> new SearchViewState(false, null, error)); } }
23. public class SearchInteractor { SearchEngine searchEngine; // Makes http calls public Observable<SearchViewState> search(String searchString) { return searchEngine.searchFor(searchString) // Observable<List<Product>> .map(products -> new SearchViewState(false, products, null)) .startWith(new SearchViewState(true, null, null)) .onErrorReturn(error -> new SearchViewState(false, null, error)); } }
24. public class SearchInteractor { SearchEngine searchEngine; // Makes http calls public Observable<SearchViewState> search(String searchString) { return searchEngine.searchFor(searchString) // Observable<List<Product>> .map(products -> new SearchViewState(false, products, null)) .startWith(new SearchViewState(true, null, null)) .onErrorReturn(error -> new SearchViewState(false, null, error)); } }
25. public class SearchInteractor { SearchEngine searchEngine; // Makes http calls public Observable<SearchViewState> search(String searchString) { return searchEngine.searchFor(searchString) // Observable<List<Product>> .map(products -> new SearchViewState(false, products, null)) .startWith(new SearchViewState(true, null, null)) .onErrorReturn(error -> new SearchViewState(false, null, error)); } }
26. public class SearchInteractor { SearchEngine searchEngine; // Makes http calls public Observable<SearchViewState> search(String searchString) { return searchEngine.searchFor(searchString) // Observable<List<Product>> .map(products -> new SearchViewState(false, products, null)) .startWith(new SearchViewState(true, null, null)) .onErrorReturn(error -> new SearchViewState(false, null, error)); } }
27. Search … searchIntent view.render( model )
28. C searchIntent filter() C view.render( model )
29. Ca searchIntent filter() C Ca view.render( model )
30. Cam searchIntent Cam filter() C Ca view.render( model )
31. Cam searchIntent filter() flatMap() view.render( model ) Cam C Ca Cam
32. Cam searchIntent filter() flatMap() startWith( new Loading() ) Cam C Ca Cam
33. Cam searchIntent filter() flatMap() startWith( new Loading() ) L view.render( SearchViewState.Loading) Cam C Ca Cam
34. Cam searchIntent filter() flatMap() startWith( new Loading() ) L view.render( SearchViewState.Loading) Cam C Ca Cam
35. Cam searchIntent filter() flatMap() startWith( new Loading() ) L view.render( SearchViewState.Loading) Cam C Ca Cam
36. Cam searchIntent filter() flatMap() startWith( new Loading() ) L view.render( SearchViewState.Loading) Cam C Ca Cam
37. Cam searchIntent filter() flatMap() startWith( new Loading() ) L view.render( SearchViewState.Loading) Cam C Ca Cam
38. Cam searchIntent filter() flatMap() startWith( new Loading() ) L Cam C Ca Cam Cam
39. Cam searchIntent filter() flatMap() startWith( new Loading() ) L Cam C Ca Cam Cam
40. Cam searchIntent filter() flatMap() startWith( new Loading() ) L Cam C Ca Cam Cam
41. Cam searchIntent filter() flatMap() startWith( new Loading() ) L Cam C Ca Cam Cam
42. Cam searchIntent filter() flatMap() startWith( new Loading() ) L map( new SR() ) Cam C Ca Cam Cam
43. Cam searchIntent filter() flatMap() startWith( new Loading() ) L map( new SR() ) Cam C Ca Cam Cam
44. Cam searchIntent filter() flatMap() startWith( new Loading() ) L map( new SR() ) SR view.render( SearchViewState.SearchResult ) Cam C Ca Cam Cam
45. Cam searchIntent filter() flatMap() startWith( new Loading() ) L map( new SR() ) SR view.render( SearchViewState.SearchResult ) Cam C Ca Cam Cam
46. Cam searchIntent filter() flatMap() startWith( new Loading() ) L map( new SR() ) SR view.render( SearchViewState.SearchResult ) Cam C Ca Cam Cam
49. public interface HomeView { Observable<Boolean> loadFirstPageIntent(); Observable<Boolean> loadNextPageIntent(); Observable<Boolean> pullToRefreshIntent(); Observable<String> loadAllProductsFromCategoryIntent(); void render(HomeViewState viewState); }
50. class HomePresenter extends MviBasePresenter<HomeView> { private final HomeFeedLoader feedLoader; @Override protected void bindIntents() { Observable<PartialState> firstPage = ... ; Observable<PartialState> pullToRefresh = ... ; Observable<PartialState> nextPage = ... ; Observable<PartialState> loadMoreFromCategory = ... ; Observable<PartialState> allIntents = Observable.merge(firstPage, pullToRefresh, nextPage, loadMoreFromCategory); Observable<HomeViewState> stateObservable = allIntents.scan(this::viewStateReducer) subscribeViewState(stateObservable, HomeView::render); }
51. public HomeViewState reducer( HomeViewState previous, Foo foo ) { HomeViewState newState; // compute the new State // by taking previous state and foo into account return newState; }
52. CONCLUSION • Model reflecting State • Unidirectional data flow • Pure Functions • Readable Code • Easy to test : assertEquals( expectedModel, model );
53. THANKS hannesdorfmann.com github.com/sockeqwe/mosby