[Yonatan Levin] Architecture Components. The one that got away

Presentation from GDG DevFest Ukraine 2017 - the biggest community-driven Google tech conference in the CEE.

Learn more at: https://devfest.gdg.org.ua

Transcript

1. Yonatan V.Levin levin.yonatan parahall Google Developer Expert
2. >100 Cities > 30M users Ruby, Go, Python, Microservices Ooooops...
3. Making genetic tests accessible
4. > 2000 members Largest Android Active Community
5. Ask questions. It’s for you.
7. public boolean onClick(View view) { OrderApi client = mRetrofitManager.createRetrofitClient(OrderApi.class); client.getIndex(new Callback<List<Order>>() { @Override public void onResponse(Call<List<Order>> call, Response<List<Order>> response) { mDB.update(response.body()); Fragment orderListFragment = new OrderListFragment(); getSupportFragmentManager().beginTransaction() .add(R.id.fragment_container, orderListFragment, OrderListFragment.TAG) .commit(); } @Override public void onFailure(Call<List<Order>> call, Throwable t) { declineDialog.show(); } }); }
8. public boolean onClick(View view) { OrderApi client = mRetrofitManager.createRetrofitClient(OrderApi.class); client.getIndex(new Callback<List<Order>>() { @Override public void onResponse(Call<List<Order>> call, Response<List<Order>> response) { mDB.update(response.body()); Fragment orderListFragment = new OrderListFragment(); getSupportFragmentManager().beginTransaction() .add(R.id.fragment_container, orderListFragment, OrderListFragment.TAG) .commit(); } @Override public void onFailure(Call<List<Order>> call, Throwable t) { declineDialog.show(); } }); }
9. public boolean onClick(View view) { OrderApi client = mRetrofitManager.createRetrofitClient(OrderApi.class); client.getIndex(new Callback<List<Order>>() { @Override public void onResponse(Call<List<Order>> call, Response<List<Order>> response) { mDB.update(response.body()); Fragment orderListFragment = new OrderListFragment(); getSupportFragmentManager().beginTransaction() .add(R.id.fragment_container, orderListFragment, OrderListFragment.TAG) .commit(); } @Override public void onFailure(Call<List<Order>> call, Throwable t) { declineDialog.show(); } }); }
10. public boolean onClick(View view) { OrderApi client = mRetrofitManager.createRetrofitClient(OrderApi.class); client.getIndex(new Callback<List<Order>>() { @Override public void onResponse(Call<List<Order>> call, Response<List<Order>> response) { mDB.update(response.body()); Fragment orderListFragment = new OrderListFragment(); getSupportFragmentManager().beginTransaction() .add(R.id.fragment_container, orderListFragment, OrderListFragment.TAG) .commit(); } @Override public void onFailure(Call<List<Order>> call, Throwable t) { declineDialog.show(); } }); }
11. public boolean onClick(View view) { OrderApi client = mRetrofitManager.createRetrofitClient(OrderApi.class); client.getIndex(new Callback<List<Order>>() { @Override public void onResponse(Call<List<Order>> call, Response<List<Order>> response) { mDB.update(response.body()); Fragment orderListFragment = new OrderListFragment(); getSupportFragmentManager().beginTransaction() .add(R.id.fragment_container, orderListFragment, OrderListFragment.TAG) .commit(); } @Override public void onFailure(Call<List<Order>> call, Throwable t) { declineDialog.show(); } }); }
12. public boolean onClick(View view) { OrderApi client = mRetrofitManager.createRetrofitClient(OrderApi.class); client.getIndex(new Callback<List<Order>>() { @Override public void onResponse(Call<List<Order>> call, Response<List<Order>> response) { mDB.update(response.body()); Fragment orderListFragment = new OrderListFragment(); getSupportFragmentManager().beginTransaction() .add(R.id.fragment_container, orderListFragment, OrderListFragment.TAG) .commit(); } @Override public void onFailure(Call<List<Order>> call, Throwable t) { declineDialog.show(); } }); }
13. public boolean onClick(View view) { OrderApi client = mRetrofitManager.createRetrofitClient(OrderApi.class); client.getIndex(new Callback<List<Order>>() { @Override public void onResponse(Call<List<Order>> call, Response<List<Order>> response) { mDB.update(response.body()); Fragment orderListFragment = new OrderListFragment(); getSupportFragmentManager().beginTransaction() .add(R.id.fragment_container, orderListFragment, OrderListFragment.TAG) .commit(); } @Override public void onFailure(Call<List<Order>> call, Throwable t) { declineDialog.show(); } }); }
14. public boolean onClick(View view) { OrderApi client = mRetrofitManager.createRetrofitClient(OrderApi.class); client.getIndex(new Callback<List<Order>>() { @Override public void onResponse(Call<List<Order>> call, Response<List<Order>> response) { mDB.update(response.body()); Fragment orderListFragment = new OrderListFragment(); getSupportFragmentManager().beginTransaction() .add(R.id.fragment_container, orderListFragment, OrderListFragment.TAG) .commit(); } @Override public void onFailure(Call<List<Order>> call, Throwable t) { declineDialog.show(); } }); }
15. Events Timeline Activity Created Network call in progress ... Activity Destroyed onResponse() called
16. Potential problems • Dependency management • Memory leaks • Crash • Object Status • Code coupling • Non testable • Not reusable
18. Android Architecture Components
19. Together or Separately.
21. The best architecture is the one that YOU can easily understand, explain to others and rapidly iterate over new features with minimal code refactoring.
23. “Act Locally, Sync Globally” Yigit Boyar
24. Sync Users Get Profiles ProfileDao Select * from profile Get Profiles I’m ready View ViewModel Profiles Repository Profile Network DataSource SQLite Very fast API GET http://.../profiles
25. List<Profiles> ProfileDao Profiles List<Profile> View ViewModel Profiles Repository Profile Network DataSource SQLite Very fast API Show Profiles
26. Show Profiles Response profiles.json List<Profile> List<Profile> ProfileDao Update Profiles table List<Profile> View ViewModel Profile Repository Profile Network DataSource SQLite Very fast API
27. ProfileDao View ViewModel Profiles Repository Profile NetworkDataSource SQLite Very fast API Room LiveData<List<Profile> LiveData<Profile[]> Observe Observe LifecycleOwner
28. Room Persistence Library
30. @Entity public class Profile { @PrimaryKey @NonNull private String name; private String imageUrl; private Integer age; private String location; }
31. @Dao public interface ProfileDao { @Query("SELECT * FROM Profile") LiveData<List<Profile>> getProfiles(); @Insert(onConflict = OnConflictStrategy.REPLACE) void bulkInsert(Profile... profile); @Query("DELETE FROM Profile") void deleteProfiles(); @Query("SELECT COUNT(NAME) FROM Profile") int countProfiles(); }
32. @Dao public interface ProfileDao { @Query("SELECT * FROM Profile") LiveData<List<Profile>> getProfiles(); @Insert(onConflict = OnConflictStrategy.REPLACE) void bulkInsert(Profile... profile); @Query("DELETE FROM Profile") void deleteProfiles(); @Query("SELECT COUNT(NAME) FROM Profile") int countProfiles(); }
33. @Dao public interface ProfileDao { @Query("SELECT * FROM Profile") LiveData<List<Profile>> getProfiles(); @Insert(onConflict = OnConflictStrategy.REPLACE) void bulkInsert(Profile... profile); @Query("DELETE FROM Profile") void deleteProfiles(); @Query("SELECT COUNT(NAME) FROM Profile") int countProfiles(); }
34. @Dao public interface ProfileDao { @Query("SELECT * FROM Profile") LiveData<List<Profile>> getProfiles(); @Insert(onConflict = OnConflictStrategy.REPLACE) void bulkInsert(Profile... profile); @Query("DELETE FROM Profile") void deleteProfiles(); @Query("SELECT COUNT(NAME) FROM Profile") int countProfiles(); }
35. @Dao public interface ProfileDao { @Query("SELECT * FROM Profile") LiveData<List<Profile>> getProfiles(); @Insert(onConflict = OnConflictStrategy.REPLACE) void bulkInsert(Profile... profile); @Query("DELETE FROM Profile") void deleteProfiles(); @Query("SELECT COUNT(NAME) FROM Profile") int countProfiles(); }
36. @Database(entities = { Profile.class }, version = 1) public abstract class AppDatabase extends RoomDatabase { public abstract ProfileDao profileDao(); } AppDatabase db = Room.databaseBuilder(getApplicationContext(), AppDatabase.class, "database-name").build();
37. @Database(entities = { Profile.class }, version = 1) public abstract class AppDatabase extends RoomDatabase { public abstract ProfileDao profileDao(); } AppDatabase db = Room.databaseBuilder(getApplicationContext(), AppDatabase.class, "database-name").build();
38. @Module public class AppModule { @Provides @Singleton AppDatabase providesDatabase(Context context) { return Room.inMemoryDatabaseBuilder(context, AppDatabase.class).build(); } } Our example - Adding Dagger2
39. LiveData component
40. LiveData what? • Gets updates to the data while the Lifecycle is in an active state (STARTED or RESUMED) • Is removed when the LifecycleOwner is destroyed • Gets up-to-date data when the LifecycleOwner restarts due to a configuration change or is restarted from the back stack This helps to eliminate many pathways for memory leaks, and reduces crashes by avoiding updates to stopped activities.
41. Usage private LiveData<List<Profile>> profiles; private void subscribeToDbChanges() { profiles = mDb.profileDao().getProfiles(); profiles.observe(this, new Observer<List<Profile>>() { @Override public void onChanged(@Nullable List<Profile> profiles) { //update UI } });
42. Usage private LiveData<List<Profile>> profiles; private void subscribeToDbChanges() { profiles = mDb.profileDao().getProfiles(); profiles.observe(this, new Observer<List<Profile>>() { @Override public void onChanged(@Nullable List<Profile> profiles) { //update UI } }); this LifeCycleOwner
43. LiveData<List<Profile>> networkData = profileNetworkDataSource.getCurrentProfiles(); networkData.observeForever(new Observer<List<Profile>>() { @Override public void onChanged(@Nullable List<Profile> profilesFromNetwork) { //insert to DB } });
44. LiveData<List<Profile>> networkData = profileNetworkDataSource.getCurrentProfiles(); networkData.observeForever(new Observer<List<Profile>>() { @Override public void onChanged(@Nullable List<Profile> profilesFromNetwork) { //insert to DB } });
45. MutableLiveData MutableLiveData<List<Profile>> mDownloadedProfiles; public void provideLoadedProfiles(List<Profile> profiles) { mDownloadedProfiles.postValue(profiles); //OR mDownloadedProfiles.setValue(profiles); }
46. MutableLiveData MutableLiveData<List<Profile>> mDownloadedProfiles; public void provideLoadedProfiles(List<Profile> profiles) { mDownloadedProfiles.postValue(profiles); //OR mDownloadedProfiles.setValue(profiles); }
47. LifeCycle Component
48. LifeCycle Abstract class Has Event and State Dispatching changes in States via Events to Observers
50. implementation "com.android.support:appcompat-v7:26.1.0" package android.support.v4.app; class SupportActivity extends Activity implements LifecycleOwner class Fragment implements LifecycleOwner class CustomLifeCycleOwner implements LifecycleOwner public interface LifecycleOwner { Lifecycle getLifecycle(); }
51. LifeCycleObserver public class MyObserver implements LifecycleObserver { @OnLifecycleEvent(Lifecycle.Event.ON_RESUME) public void onResume() { } @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE) public void onPause() { } } aLifecycleOwner.getLifecycle().addObserver(new MyObserver());
52. LifeCycleObserver public class MyObserver implements LifecycleObserver { @OnLifecycleEvent(Lifecycle.Event.ON_RESUME) public void onResume() { } @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE) public void onPause() { } } aLifecycleOwner.getLifecycle().addObserver(new MyObserver());
53. LifeCycleObserver public class MyObserver implements LifecycleObserver { @OnLifecycleEvent(Lifecycle.Event.ON_RESUME) public void onResume() { } @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE) public void onPause() { } } aLifecycleOwner.getLifecycle().addObserver(new MyObserver());
56. What is it? Preparing the data for the UI Stores* UI Data Separate out view data ownership from UI controller logic Automatically retained during configuration changes React on Events from UI
58. Creation private MainViewModel mainViewModel; @Override protected void onCreate(Bundle savedInstanceState) { //... mainViewModel = ViewModelProviders.of(this).get(MainViewModel.class); //... subscribeUiUpdates(); } private void subscribeUiUpdates() { mainViewModel.getProfiles().observe(this, this); }
59. Creation private MainViewModel mainViewModel; @Override protected void onCreate(Bundle savedInstanceState) { //... mainViewModel = ViewModelProviders.of(this).get(MainViewModel.class); //... subscribeUiUpdates(); } private void subscribeUiUpdates() { mainViewModel.getProfiles().observe(this, this); }
60. Creation private MainViewModel mainViewModel; @Override protected void onCreate(Bundle savedInstanceState) { //... mainViewModel = ViewModelProviders.of(this).get(MainViewModel.class); //... subscribeUiUpdates(); } private void subscribeUiUpdates() { mainViewModel.getProfiles().observe(this, this); }
61. public class MainActivityViewModel extends ViewModel { ProfileRepository profileRepository; private LiveData<List<Profile>> profiles; MainActivityViewModel(ProfileRepository profileRepository) { this.profileRepository = profileRepository; profiles = profileRepository.getProfiles(); } public LiveData<List<Profile>> getProfiles() { return profiles; } }
62. public class MainActivityViewModel extends ViewModel { ProfileRepository profileRepository; private LiveData<List<Profile>> profiles; MainActivityViewModel(ProfileRepository profileRepository) { this.profileRepository = profileRepository; profiles = profileRepository.getProfiles(); } public LiveData<List<Profile>> getProfiles() { return profiles; } }
63. public class MainActivityViewModel extends ViewModel { ProfileRepository profileRepository; private LiveData<List<Profile>> profiles; MainActivityViewModel(ProfileRepository profileRepository) { this.profileRepository = profileRepository; profiles = profileRepository.getProfiles(); } public LiveData<List<Profile>> getProfiles() { return profiles; } }
64. Back to ...
65. Get Profiles UserDao View ViewModel Users Repository UserNetworkDataSource SQLite Very fast API Room LiveData<List<User> LiveData<User[]> Observe Observe LifecycleOwner Load Profiles
66. Update Profile table List<Profile> Response profiles.js on UserDao View ViewModel Users Repository UserNetworkDataSource SQLite Very fast API Room LiveData<List<User> LiveData<User[]> LifecycleOwner List<Profile> List<Profile>
67. View ViewModel Users Repository UserNetworkDataSource Very fast API Room LiveData<List<User> LiveData<User[]> Observe Observe LifecycleOwner Firebase JobDispatcher Recurring sync New match, messages Firebase Push Notification
68. https://github.com/parahall/StarWarsTinder
69. Should I change my architecture because cool guy on stage said that?
70. You have a force. Use it wisely
71. Questions ?
72. Yonatan V.Levin levin.yonatan parahall Google Developer Expert
73. Q&A (Additional code)
74. @Inject MainViewModelFactory factory; @Override protected void onCreate(Bundle savedInstanceState) { MainViewModel mainViewModel = ViewModelProviders.of(this, factory). get(MainViewModel.class); mainViewModel.getProfiles().observe(this, this); } @Override public void onChanged(@Nullable List<Profile> profiles) { //update UI }
75. ProfileRepository profileRepository; private LiveData<List<Profile>> profiles; MainViewModel(ProfileRepository profileRepository) { this.profileRepository = profileRepository; profiles = profileRepository.getProfiles(); } public LiveData<List<Profile>> getProfiles() { return profiles; }
76. @Inject public ProfileRepository(final AppDatabase db, ProfileNetworkDataSource dataSource) { LiveData<List<Profile>> networkData = dataSource.getCurrentProfiles(); networkData.observeForever(profilesFromNetwork -> new Thread(() -> { deleteOldData(); db.profileDao().bulkInsert(profilesFromNetwork); }).start()); }
77. public LiveData<List<Profile>> getProfiles() { initializeData(); return db.profileDao().getProfiles(); } private void initializeData() { new Thread(() -> { if (isFetchNeeded()) { startFetchProfilesService(); } }).start(); }
78. public LiveData<List<Profile>> getProfiles() { initializeData(); return db.profileDao().getProfiles(); } private void initializeData() { new Thread(() -> { if (isFetchNeeded()) { startFetchProfilesService(); } }).start(); }