That Fresh Mobile Smell

Android Presenter First talk at TriDroid West.

1. That Fresh Mobile Smell ! TriDroidWest 2.20.2014 Fred Medlin
5. NOT BUGS SYMPTOM OF A DEEPER PROBLEM WEAKNESS THAT SLOWS DOWN DEVELOPMENT CODE SMELLS
6. 976 LINES KNOWS TOO MUCH DOES TOO MUCH LARGE CLASS => GOD OBJECT
7. BUSINESS DATA AND LOGIC MODEL USER STORY BEHAVIOR USER INTERACTIONS PRESENTER VIEW PRESENTER FIRST
8. BUSINESS DATA AND LOGIC MODEL USER STORY BEHAVIOR USER INTERACTIONS PRESENTER VIEW PRESENTER FIRST
9. BUSINESS DATA AND LOGIC MODEL USER STORY BEHAVIOR USER INTERACTIONS PRESENTER VIEW PRESENTER FIRST
10. HOW IT’S DONE 1.Start with a user story 2.Stub a presenter 3.Write interface methods for model and view 4.Add presenter tests to confirm the methods were called
11. 1. USER STORY Using my current latitude and longitude, find and display the nearest geo-tagged wikipedia entry.
12. 2. STUB PRESENTER public class GeoWikiPresenter {! private GeoWikiModel model;! private GeoWikiView view;! ! public GeoWikiPresenter(GeoWikiModel model, GeoWikiView view) {! this.model = model;! this.view = view;! }! }!
13. 3. MODEL/VIEW INTERFACE METHODS public interface GeoWIkiModel {! !void findLocation();! !void queryArticles(float latitude, float longitude);! }! ! public interface GeoWikiView {! !void showProgress();! !void hideProgress();! !void displayPage(String url);! }!
14. 4. PRESENTER TESTS public class GeoWikiPresenterTest {! !@Mock GeoWikiModel model;! !@Mock GeoWikiView view;! !GeoWikiPresenter presenter;! ! !@Before! !public void setup() {! !!Mockito.initAnnotations(this);! !!presenter = new GeoWikiPresenter(model, view);! !}! }!
15. 4. PRESENTER TESTS (2) @Test! ! public void searchesForLocation() {! ! ! verify(model).findLocation();! ! ! verify(view).showProgress();! ! }! ! ! @Test! ! public void queryWikiLocation() {! ! ! presenter.onLocationFound(new FoundLocationEvent(lat, lon));! ! ! verify(model).queryArticles(lat, lon);! ! }!
16. 4. PRESENTER TESTS (3) public class GeoWikiPresenter {! private GeoWikiModel model;! private GeoWikiView view;! ! public GeoWikiPresenter(GeoWikiModel model, GeoWikiView view) {! this.model = model;! this.view = view;! model.findLocation();! view.showProgress();! ! @Subscribe! public void onLocationFound(FoundLocationEvent event) {! ! model.queryArticles(event.getLatitude(), event.getLongitude());! }! ! @Subscribe! public void onArticleFound(FoundArticleEvent event) {! ! view.hideProgress();! ! view.displayPage(event.getUrl());! }! }! }!
18. 3. MODEL/VIEW INTERFACE METHODS public interface GeoWIkiModel {! !void findLocation();! !void queryArticles(float latitude, float longitude);! }! ! public interface GeoWikiView {! !void showProgress();! !void hideProgress();! !void displayPage(String url);! }!
19. FRESH public class MainActivity extends Activity {! ! ! GeoWikiPresenter presenter;! ! ! @Override! ! public void onCreate(Bundle savedInstanceState) {! ! ! super.onCreate(savedInstanceState);! ! ! setContentView(R.layout.activity_main);! ! ! presenter = new GeoWikiPresenter(new GeoWikiModelImpl(), new GeoWikiViewImpl());! ! }! ! ! @Override! ! public void onPause() {! ! ! super.onPause();! ! ! BusProvider.unregister(presenter);! ! }! ! ! @Override! ! public void onResume() {! ! ! super.onPause();! ! ! BusProvider.register(presenter);! ! }! }!
20. • Traditional SW mistake • Focuses on invisible things MODEL FIRST • Seems reasonable, but… • Views attract strong feeling • High rate of changes • Hard to test VIEW FIRST ALTERNATIVES?
22. Fred Medlin fred@medl.in @fmedlin
23. LINKS Mockito - https://code.google.com/p/mockito/ Otto - http://square.github.io/otto/
24. All photos via Creative Commons Licenses from flickr.com ! - Attribution-NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0) - (mbshane) http://www.flickr.com/photos/mbshane/3165456548/ - (reid-bee) http://www.flickr.com/photos/reid-bee/5521024764/ - (captain_chickenpants) http://www.flickr.com/photos/captain_chickenpants/320441513/ - (RosenRakuen) http://www.flickr.com/photos/91134569@N05/8365293556/ ! Attribution-NonCommercial-ShareAlike 2.0 Generic (CC BY-NC-SA 2.0) - (clintjcl) http://www.flickr.com/photos/clintjcl/2708117471/ ! Attribution 2.0 Generic (CC BY 2.0) - (jeffreyww) http://www.flickr.com/photos/jeffreyww/4867984686/ - (quietlyurban.com) http://www.flickr.com/photos/83118222@N06/9689975423/ ! Attribution-NonCommercial 2.0 Generic (CC BY-NC 2.0) - (hatalmas) http://www.flickr.com/photos/hatalmas/6094281702/ PHOTO CREDITS