Fundamentals #10 - Architecture & Tying things up

Closing talk on Android fundamentals course: architecture design patterns and suggested implementation, with new Android Architecture Components.

Transcript

1. Architecture & Tying things up Fundamentals #10 8/1/2018 Britt Barak
2. One thing is sure Everything will change. Quick.
3. Our Goals - Write quicker - Change easily - Easy for others to understand
4. Our Goals - Write quicker - Change easily - Easy for others to understand - Rely on the code (testable) - Robust - Scalable
5. Who loves Jelly Beans?
10. Where to start?
12. Clean Architecture https://8thlight.com/blog/uncle-bob/2012 /08/13/the-clean-architecture.html
13. Presentation Layer Data Layer Domain Layer
14. Presentation Layer
15. class JellyBeanViewModel extends ViewModel { String flavor; int r; int g; int b; boolean isLoading;
16. Data Layer
17. class JellyBeanViewModel String flavor; int r; int g; int b; boolean isLoading; class JellyBean String flavor; String color;
18. Presentation Data ViewModel DataModel ?
19. Presentation Data Domain DataModel Interactor ViewModel
20. Domain Layer
21. Presentation Layer Data Layer Domain Layer
22. Communication: Architecture patterns
24. MVC Model View Controller
25. Presentation Domain View Controller User Input Data DataModel
26. MVP Model View Presenter
27. Presentation Domain View Presenter User Input ViewModel
28. Presentation Domain View Presenter User Input ViewModel SAVE Data DataModel
29. What if I change the UI? (also, is this unit testiable?)
30. Presentation Domain View Presenter User Input ViewModel
31. Presentation Domain View Presenter User Input IView ViewModel IPresenter
32. Questions?
33. What can the Presenter do?
34. What if we POST instead of PM?
35. Presentation Domain View Presenter User Input IView ViewModel IPresenter ViewModel I Changed
36. Presenter doesn’t know View No contract needed
37. Presentation Domain View Presenter User Input IView ViewModel IPresenter ViewModel I Changed
38. Presentation Domain View Presenter User Input ViewModel
39. Presentation Domain View ViewModel User Input
40. MVVM Model View ViewModel
41. Questions?
42. This are Patterns & Concepts - Many variants - Which should you use? - Are there others?
43. MVI - Model View Intent http://hannesdorfmann.com/android/mosby3-mvi-1 https://github.com/sockeqwe/mosby https://github.com/Arello-Mobile/Moxy
45. Let’s Play
47. class JellyBeanViewModel extends ViewModel { String flavor; int r; int g; int b;
48. @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_add_bean); setViewModel() setUi(); }
49. void setViewModel(){ this.viewModel = new JellyBeanViewModel(); }
50. UI represents the ViewModel state
51. Presentation Domain Layer UseCase View ViewModel User Input
52. 1. Update the viewModel
53. public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { switch (seekBar.getId()) { case R.id.sb_r: viewModel.setR(progress); break; //...
54. 2. View Model notifies
55. - Data binding - RxJava (/RxAndroid) - Event Bus - LiveData How to notify?
56. LiveData - Observable data holder class - Lifecycle-aware - Updates only on started / resumed state - Removes itself on destroyed state - No memory leaks https://developer.android.com/topic/libraries/architecture/livedata.html
57. public class JellyBeanViewModel extends ViewModel { String flavor; LiveData<Integer> r; LiveData<Integer> g; LiveData<Integer> b;
58. public class JellyBeanViewModel extends ViewModel { LiveData<Integer> r; public void setR(int newR) { newR = validate(newR); r.setValue(newR); }
59. 3. Create an observer
60. Observer<Integer> colorChangedObserver = (Integer integer) -> { beanIv.setColorFilter(viewModel.getColor()); };
61. 4. Observe ViewModel changes
62. viewModel.getR() .observe(this, colorChangedObserver); Observer is tied to this lifecycle, and will be removed as the lifecycle ends. LiveData
63. Presentation Domain Layer UseCase View ViewModel User Input
64. Questions?
65. Persisting ViewModel
67. setViewModel() -> { this.viewModel = ViewModelProviders.of(this) .get(JellyBeanViewModel.class); }
68. Save The Jelly Bean!
69. Data Layer
70. - Data Model - Repository Data Layer
71. class JellyBeanViewModel String flavor; int r; int g; int b; class JellyBean String flavor; String color;
72. - One per data type (e.g jelly bean, recipe, user….). - Encapsulates the logic of getting/setting the data. - CRUD operations (Create, Read, Update, Delete) Repository
73. class JellyBeanRepo{ }
74. class JellyBeanRepo{ LiveData<JellyBean> getJellyBean(String id){ }
75. LiveData<JellyBean> getJellyBean(String id) { return myFirebaseClient.getJellyBean(id) }
76. LiveData<JellyBean> getJellyBean(String id) { if (cache.hasJellyBean(id)){ return cache.getJellyBean(id); } else{ return myFirebaseClient.getJellyBean(id) } }
77. LiveData<JellyBean> getJellyBean(String id) { if (cache.hasJellyBean(id)){ return cache.getJellyBean(id); } else if (appDatabase.hasJellyBean(id)) { return appDatabase.jellyBeanDao().getJellyBean(id); } else{ return myFirebaseClient.getJellyBean(id) }
78. LiveData<JellyBean> getJellyBean(String id) { if (cache.hasJellyBean(id)){ return cache.getJellyBean(id); } else if (appDatabase.hasJellyBean(id)) { return appDatabase.jellyBeanDao().getJellyBean(id); } else{ return myApiClient.getJellyBean(id) }
79. Presentation Layer Data Layer ViewModel DataModel ?
80. Presentation Layer Data Layer Domain Layer DataModel Interactor ViewModel
81. Domain Layer
82. 1. Create Use Case
83. class SaveJellyBean extends UseCase { void execute() { }
84. 2. Convert Models
85. public class SaveJellyBean extends UseCase { public void execute(JellyBeanViewModel viewModel) { JellyBean data = prepareDataModel(viewModel); }
86. JellyBean prepareDataModel(JellyBeanViewModel viewModel){ String beanColorString = String.format("#%06X", (0xFFFFFF & viewModel.getColor())); JellyBean data = new JellyBean(viewModel.getFlavor(), beanColorString); return data; }
87. 3. Call Repository
88. public class SaveJellyBean extends UseCase { public void execute(JellyBeanViewModel viewModel) { JellyBean data = prepareDataModel(viewModel); repo.saveBean(data); }
89. 4. Execute
90. Presentation Layer Data Layer Domain Layer SaveJellyBean .execute() JellyBeanRepo .save()
91. Questions?
92. Reusing interactors - Edit Jelly Bean screen - Different UI - Same SaveJellyBean use case
93. Another word about Repository...
94. Data Network Service AppDatabase Cache? Domain Some Usecase Repository
95. Thank You ! goo.gl/p96gpF Read more:
96. VOTE HERE: https://goo.gl/tsmeK2
97. Code lab
98. Exercise 1. Android lifecycle-aware components goo.gl/92wWf3 2. For Sum Up: Build an App with Architecture Components goo.gl/5og51s