Effective Android Architecture - MWDC

Yet another talk on Android architecture at MWDC 2015

Transcript

1. EFFECTIVE ANDROID
   ARCHITECTURE
   

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2. Hi, I am Richa
   

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3. EFFECTIVE ANDROID
   ARCHITECTURE
   

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9. Who all has ever used
   MVC?
   

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10. MVC
    

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11. MVP ?
    MVC ?
    MVVM ?
    

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12. MODEL VIEW CONTROLLER
    Interact with DB Render Model Handle view events
    Update model
    Invoke next UI
    Table of Responsibilities
    

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13. Mobile
    Web
    Desktop
    

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15. 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
    

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16. Model
    public class CourseModel {
    Course getFromDatabase() {
    // fetch from db, or local cache
    }
    Course getFromNetwork() {
    // fetch from apis, cache when possible
    }
    }
    

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17. View
    public class ExpandableCourseListActivity
    {
    void onSaveInstanceState(Bundle b) {
    // save all expanded states
    }
    }
    

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18. Controller
    void onClick() {}
    void onModelUpdated() {}
    void onNewNotification() {}
    void onLocationUpdated(Location loc) {}
    void takePhoto(Activity context) {}
    void launchView(Activity context ) {}
    

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21. MVC
    ??
    

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22. 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
    

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23. Interactor?
    

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24. JUnit +
    Mocking
    

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25. 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
    

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26. View Model ?
    

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27. JUnit +
    Mocking
    Android +
    Mocking
    Espresso +
    Mocking
    

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28. 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
    

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29. Presenter ?
    

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30. 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
    

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31. Espresso +
    Mocking
    JUnit +
    Mocking
    JUnit +
    Mocking
    Android +
    Mocking
    Data Source
    

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32. 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
    

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33. FlowController ?
    

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34. Android +
    Mocks
    

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35. 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
    

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37. Apply Dependency
    Inversion
    

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41. S ingle Responsibility Principle
    O pen/Closed Principle
    L iskov Substitution Principle
    I nterface Segregation Principle
    D ependency Inversion Principle
    

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42. Architecture is about
    Intents not Frameworks
    - Uncle Bob
    

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44. Implementation in
    Practice
    

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45. Activity
    Video
    Module
    Activity
    Quiz
    Module
    Navigation
    Main
    Activity
    Shell
    App
    Catalog
    Activity
    Catalog
    Module
    url Intent
    Intent
    Register
    with url
    Modules
    

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46. Deep links
    Shell
    App
    Video
    Activity
    Video
    Module
    Catalog
    Activity
    Catalog
    Module
    register register
    url
    Intent
    Intent
    

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47. ViewModels Save/Restore
    View
    Models
    Presenter
    Retainable
    Fragments
    Parcelables
    onSaveInstanceState
    onSaveInstanceState
    

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48. Chain of Responsibility
    View
    Presenter
    Interactor
    Network
    Persistence •Result
    •Error
    

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50. The Cons
    

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51. Dealing with context
    Presenter(Context context)
    Interactor(Context context)
    NetworkClient(Context context)
    PersistenceClient(Context context)
    context.getSystemService(“SERVICE”)
    context.startActivity(intent)
    context.startActivityForResult(intent)
    

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52. Tedium
    ~ 7 classes per feature/module
    

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53. Adopting as a team
    Educating new hires
    

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54. Key Takeaways
    

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55. Ship the latest ideas
    

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56. Refactor or Not?
    

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57. Validate
    

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58. Iterate, Iterate, Iterate
    

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59. Code Demo - Sample app
    

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60. Source Code
    https://github.com/richk/
    CourseraDemoApp
    

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61. Classes
    • MainActivity
    • CatalogFlowController
    • CatalogActivity
    • CatalogPresenter
    • CatalogViewModel
    • CatalogInteractor
    

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62. MainActivity
    void onCreate() {
    CatalogFlowController.getInstance()
    .launchCatalogActivity();
    }
    

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63. CatalogFlowController
    void launchCatalogActivity(Context c) {
    Intent intent = …;
    c.startActivity(intent)
    }
    

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64. CatalogActivity
    CatalogPresenter presenter;
    void onCreate() {
    presenter = new CatalogPresenter(this);
    }
    

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65. CatalogActivity
    void onResume() {
    Action1 action = ;
    presenter.subscribeToUpdates(action)
    }
    

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66. CatalogActivity
    void onPause() {
    presenter.unsubscribeToUpdates();
    }
    

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67. CatalogPresenter
    CatalogInteractor interactor;
    CatalogPresenter(Context c) {
    viewModel = new CatalogViewModel();
    interactor = new CatalogInteractor(c);
    loadCatalog();
    }
    

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68. CatalogPresenter
    void loadCatalog() {
    interactor.loadCourses()
    .subscribe(new Action1<>() {
    @Override
    public void call(List courses) {
    // action
    }
    });
    }
    

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69. CatalogPresenter
    void subscribeToUpdates(Action1 a) {
    viewModel.subscribeToUpdates(a);
    }
    void unsubscribeToUpdates() {
    viewModel.unsubscribeToUpdates();
    }
    

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70. CatalogViewModel
    public final BehaviorSubject catalog =
    BehaviorSubject.create();
    public void subscribeToCatalog(Action1 action) {
    catalog.subscribe(action);
    }
    public void unsubscribeToCatalog() {
    catalog.unsubscribe();
    }
    

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71. CatalogInteractor
    Context mContext;
    public CatalogInteractor(Context context) {
    mContext = context;
    }
    public Observable loadCatalog() {
    return catalogDataSource.loadCatalog();
    }
    

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74. Coursera is hiring!
    

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75. Questions ?
    

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76. @richa123
    rkhandelwal@coursera.org
    richk
    in/richak
    Thank You
    

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