Android Architecture

Android Architecture talk presented at 360Andev

Transcript

1. Effective Android Architecture Richa Khandelwal Growth/Android/Front-End Engineer at Coursera
3. ▪ Challenges ▪ Finding the right architecture fit ▪ Validation ▪ Practice makes perfect! ▪ Demo and Samples ▪ Cons ▪ Key Takeaways Structure of the talk
4. Available on Google Play Store Place your screenshot here Android App 1,825+ COURSES 18M+ LEARNERS 141+ PARTNERS
5. 109% increase in mobile usage since last year 24 % use mobile only 40 % use mobile and desktop
6. Over 500k (and growing) new learners join Coursera every month
7. Cross team Tightly aligned, loosely coupled Faster MVPs Learn fast, fail fast Network Speeds Edge, 2G, Spotty
8. Who all has ever used MVC?
9. MVC
10. Where to Begin
11. MVP ? MVC ? MVVM ? VIPER ?
12. MODEL VIEW CONTROLLER Manage application data Render model Handle view events Interact with model Invoke next UI Table of Responsibilities
13. Mobile Web Desktop
15. MODEL VIEW CONTROLLER Manage data from network Render model Handle view events Manage data from local storage Manage view state Interact with model Manage model consistency Navigation Interact with system components Interact with system events Update view on model changes or system events
16. Model public class CourseModel { Course getFromDatabase() { // fetch from db, or local cache } Course getFromNetwork() { // fetch from apis, cache when possible } }
17. View public class ExpandableCourseListActivity { void onSaveInstanceState(Bundle b) { // save all expanded states } }
18. Controller void onClick() {} void onModelUpdated() {} void onNewNotification() {} void onLocationUpdated(Location loc) {} void takePhoto(Activity context) {} void launchView(Activity context ) {}
20. MVC ??
21. MODEL VIEW CONTROLLER Manage data from local storage Render model Handle view events Manage data from network Manage view state Interact with model Manage model consistency Navigation Interact with system components Interact with system events Update view on model changes or system events
22. Interactor?
24. MODEL VIEW CONTROLLER INTERACTOR Manage data from local storage Render view data Handle view events Interact with external entities Manage data from network Manage view data/ updates Navigation Manage model consistency Forward view data updates to view
25. View Model ?
27. MODEL VIEW CONTROLLER INTERACTOR VIEW MODEL Manage data from local storage Render view model Handle view events Interact with external entities Manage view data Manage data from network Navigation Manage model consistency Manage view model
28. Presenter ?
29. MODEL VIEW PRESENTER INTERACTOR VIEW MODEL Manage data from local storage Render view model Handle view events Interact with external entities Manage view data Manage data from network Navigation Manage model consistency Manage view model
30. Data Source
31. ENTITIES VIEW PRESENTER INTERACTOR VIEW MODEL Represent model objects Render view model Handle view events Interact with external entities Manage view data Navigation Manage view model
32. FlowController ?
33. coursera-android://app/<feature_url>
34. ENTITIES VIEW PRESENTER INTERACTOR VIEW MODEL FLOW CONTROLLER Represent model objects Render view model Manage view events and view model Interact with external entities Manage view data Navigation
35. Apply Dependency Inversion
36. Data Source
39. Espresso + Mocking JUnit + Mocking Android/ JUnit + Mocking Android/ JUnit + Mocks Data Source
41. @AutoValue @AutoParcel https://github.com/google/auto V2 - and beyond ▪ Good developers write code, great developers generate! ▪ When code is generated, why write tests? ▪ Use code generation and annotation processing heavily. ▹ Custom annotation processors - Data source policies, Routing, Model, Event Tracking generation. https://github.com/rharter/auto-value-gson
42. V2 - and beyond ▪ Data Source layer can evolve separately from the rest of the application. ▪ Load all data on critical path. ▪ Leverage common interfaces like `onLoad` in the Presenters to prefetch data on critical path of user experience.
43. Code Demo - Sample app
44. Source Code https://github.com/richk/ CourseraDemoApp
45. Classes • MainActivity • FlowController • CatalogActivity • CatalogPresenter • CatalogViewModel • CatalogInteractor
46. MainActivity void onCreate() { FlowController.getInstance() .launchCatalogActivity(this); }
47. FlowController void launchCatalogActivity(Context c) { Intent intent = …; c.startActivity(intent) }
48. CatalogActivity CatalogPresenter presenter; void onCreate() { presenter = new CatalogPresenter(this); }
49. CatalogActivity void onResume() { Action1<Catalog> action = ; presenter.subscribeToUpdates(action) }
50. CatalogActivity void onPause() { presenter.unsubscribeToUpdates(); }
51. CatalogPresenter CatalogInteractor interactor; CatalogPresenter(Context c) { viewModel = new CatalogViewModel(); interactor = new CatalogInteractor(c); loadCatalog(); }
52. CatalogViewModel // Parcelable public final Catalog catalog = new Catalog();
53. CatalogInteractor Context mContext; public CatalogInteractor(Context context) { mContext = context; } public Observable loadCatalog() { return catalogDataSource.loadCatalog(mContext.getApplication( )); }
54. CatalogPresenter void loadCatalog() { interactor.loadCourses().observeOn(AndroidSchedulers.mainThread()) .subscribe(new Action1<>() { @Override public void call(List<Course> courses) { // update the view model } }); }
56. The Cons
57. Dealing with context Presenter(Context context) Interactor(Context context) NetworkClient(Context context) PersistenceClient(Context context) context.getSystemService(“SERVICE”) context.startActivity(intent) context.startActivityForResult(intent)
58. Tedium ~ 4 classes per feature/module
59. Adopting as a team Educating new hires
60. Key Takeaways
61. Ship the latest ideas
62. Refactor or Not?
63. Validate
64. Iterate, Iterate, Iterate
66. We Are Hiring! Apply
67. @richa123 rkhandelwal@coursera.org richk in/richak Thank You
68. References ▪ Android dialogs - https://www.youtube.com/watch?v=VTaguVtvuYI ▪ https://github.com/square/okhttp ▪ https://github.com/square/retrofit ▪ http://google.github.io/dagger/ ▪ https://github.com/ReactiveX/RxAndroid ▪ http://360andev.com/sessions/100-libraries-i-wish-i-knew-about-when-i- started/ ▪http://360andev.com/sessions/100-eliminateboilerplate/ ▪ https://github.com/googlesamples/android-architecture ▪ http://360andev.com/sessions/100-intro-to-rxjava/
69. Questions ?