Effective Android Architecture

Transcript

1. EFFECTIVE ANDROID ARCHITECTURE
2. Hi, I am Richa
3. Hi, I am Kelvin
4. EFFECTIVE ANDROID ARCHITECTURE
10. Who all has ever used MVC?
11. MVC
13. MODEL VIEW CONTROLLER Interact with DB Render Model Handle view events Update model Invoke next UI Table of Responsibilities
14. Mobile Web Desktop
16. MODEL VIEW CONTROLLER Interact with DB Render Model Handle view events Interact with network Manage view state Update model Navigation Interact with system components Handle system events Update view on system events
17. Model public class CourseModel { Course getFromDatabase() { // fetch from db, or local cache } Course getFromNetwork() { // fetch from apis, cache when possible } }
18. View public class ExpandableCourseListActivity { void onSaveInstanceState(Bundle b) { // save all expanded states } }
19. Controller void onClick() {} void onModelUpdated() {} void onNewNotification() {} void onLocationUpdated(Location loc) {} void takePhoto(Activity context) {} void launchView(Activity context ) {}
22. MVC ??
23. MODEL VIEW CONTROLLER Interact with DB Render Model Handle view events Interact with network Manage view state Update model Navigation Interact with system components Handle system events Update view on system events
24. Interactor?
25. JUnit + Mocking
26. MODEL VIEW CONTROLLER INTERACTOR Retrieve data from DB Render Model Handle view events Interact with external entities Retrieve data from network Manage view state Navigation Forward system events to view Forward model updates to view
27. View Model ?
28. JUnit + Mocking Android + Mocking Espresso + Mocking
29. MODEL VIEW CONTROLLER INTERACTOR VIEW MODEL Retrieve data from Network Render View Model Handle view events Interact with external entities View state / behavior Retrieve data from network Navigation Update view state
30. Presenter ?
31. MODEL VIEW PRESENTER INTERACTOR VIEW MODEL Retrieve data from DB Render View Model Handle view events Interact with external entities View state / behavior Retrieve data from network Navigation Update view state
32. Espresso + Mocking JUnit + Mocking JUnit + Mocking Android + Mocking Data Source
33. ENTITIES VIEW PRESENTER INTERACTOR VIEW MODEL Get data from Data Sources Render View Model Handle view events Interact with external entities View state / behavior Navigation Update view state
34. FlowController ?
35. Android + Mocks
36. ENTITIES VIEW PRESENTER INTERACTOR VIEW MODEL FLOW CONTROLLER Get data from Data Sources Render View Model Handle view events Update view state Interact with external entities View state / behavior Navigation
38. Apply Dependency Inversion
42. S ingle Responsibility Principle O pen/Closed Principle L iskov Substitution Principle I nterface Segregation Principle D ependency Inversion Principle
43. Architecture is about Intents not Frameworks - Uncle Bob
45. Implementation in Practice
46. Activity Video Module Activity Quiz Module Navigation Main Activity Shell App Catalog Activity Catalog Module url Intent Intent Register with url Modules
47. Deep links Shell App Video Activity Video Module Catalog Activity Catalog Module register register url Intent Intent
48. ViewModels Save/Restore View Models Presenter Retainable Fragments Parcelables onSaveInstanceState onSaveInstanceState
49. Chain of Responsibility View Presenter Interactor Network Persistence •Result •Error
51. The Cons
52. Dealing with context Presenter(Context context) Interactor(Context context) NetworkClient(Context context) PersistenceClient(Context context) context.getSystemService(“SERVICE”) context.startActivity(intent) context.startActivityForResult(intent)
53. Tedium ~ 7 classes per feature/module
54. Adopting as a team Educating new hires
55. Key Takeaways
56. Ship the latest ideas
57. Refactor or Not?
58. Validate
59. Iterate, Iterate, Iterate
60. Code Demo - Sample app
61. Source Code https://github.com/richk/ CourseraDemoApp
62. Classes • MainActivity • CatalogFlowController • CatalogActivity • CatalogPresenter • CatalogViewModel • CatalogInteractor
63. MainActivity void onCreate() { CatalogFlowController.getInstance() .launchCatalogActivity(); }
64. CatalogFlowController void launchCatalogActivity(Context c) { Intent intent = …; c.startActivity(intent) }
65. CatalogActivity CatalogPresenter presenter; void onCreate() { presenter = new CatalogPresenter(this); }
66. CatalogActivity void onResume() { Action1<Catalog> action = ; presenter.subscribeToUpdates(action) }
67. CatalogActivity void onPause() { presenter.unsubscribeToUpdates(); }
68. CatalogPresenter CatalogInteractor interactor; CatalogPresenter(Context c) { viewModel = new CatalogViewModel(); interactor = new CatalogInteractor(c); loadCatalog(); }
69. CatalogPresenter void loadCatalog() { interactor.loadCourses() .subscribe(new Action1<>() { @Override public void call(List<Course> courses) { // action } }); }
70. CatalogPresenter void subscribeToUpdates(Action1 a) { viewModel.subscribeToUpdates(a); } void unsubscribeToUpdates() { viewModel.unsubscribeToUpdates(); }
71. CatalogViewModel public final BehaviorSubject<Catalog> catalog = BehaviorSubject.create(); public void subscribeToCatalog(Action1 action) { catalog.subscribe(action); } public void unsubscribeToCatalog() { catalog.unsubscribe(); }
72. CatalogInteractor Context mContext; public CatalogInteractor(Context context) { mContext = context; } public Observable loadCatalog() { return catalogDataSource.loadCatalog(); }
75. Coursera is hiring!
76. Questions ?
77. @richa123 rkhandelwal@coursera.org, kwong@coursera.org richk in/richak , in/kelvinswwong Thank You