Android Architecture Components. Do you really need them?

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Transcript

1. Android Architecture Components V. Chornenkyy Do you really need them?
2. NO
3. NO ...almost
4. No data processing in the app components
5. TransactionTooLargeException
7. Lifecycle LiveData ViewModel
8. Lifecycle aka CALLBACK LiveData aka OBSERVER ViewModel aka CONTAINER
9. LifecycleOwner.getLifecycle().addObserver(LifecycleObserver) // Lifecycle
10. LifecycleActivity -> AppCompatActivity LifecycleFragment -> support.Fragment LifecycleService ProcessLifecycleOwner // Lifecycle
11. @OnLifecycleEvent(ON_STOP) void onFirstStop() {} @OnLifecycleEvent(ON_STOP) void onSecondStop() {} @OnLifecycleEvent(ON_ANY) void onAny(LifecycleOwner source, Event event) {} // Lifecycle
12. @OnLifecycleEvent(ON_STOP) void onFirstStop() {} @OnLifecycleEvent(ON_STOP) void onSecondStop() {} @OnLifecycleEvent(ON_ANY) void onAny(LifecycleOwner source, Event event) {} // Lifecycle
13. @OnLifecycleEvent(ON_STOP) void onFirstStop() {} @OnLifecycleEvent(ON_STOP) void onSecondStop() {} @OnLifecycleEvent(ON_ANY) void onAny(LifecycleOwner source, Event event) {} // Lifecycle
14. owner.super.onCreate() Event.ON_CREATE Event.ON_DESTROY owner.super.onDestroy() // Lifecycle
15. class MyLocationListener implements LifecycleObserver { private boolean enabled = false; public MyLocationListener(Context context, Lifecycle lifecycle, Callback callback) { ... } @OnLifecycleEvent(Lifecycle.Event.ON_START) void start() { if (enabled) { // connect } } public void enable() { enabled = true; if (lifecycle.getState().isAtLeast(STARTED)) { // connect if not connected } } @OnLifecycleEvent(Lifecycle.Event.ON_STOP) void stop() { // disconnect if connected } } sample by Google
16. class CustomOwner implements LifecycleRegistry // Lifecycle
17. LiveData.observe(LifecycleOwner, data -> {}) // LiveData
18. LiveData#setValue(data) LiveData#postValue(data) // LiveData
19. LiveData#onActive() LiveData#onInactive() // LiveData
20. LiveData#observeForever(data -> {}) LiveData#removeObserver(observerAbove) LiveData#removeObservers(LifecycleOwner) // LiveData
21. Transformations#map == Rx#flatMap Transformations#switchMap == Rx#switchMap MediatorLiveData // LiveData
22. Configuration change awareness // LiveData
23. public class LocationLiveData extends LiveData<Location> { private static LocationLiveData sInstance; private LocationManager locationManager; … LocationLiveData singleton with Application context private SimpleLocationListener listener = new SimpleLocationListener() { @Override public void onLocationChanged(Location location) { setValue(location); } }; private LocationLiveData(Context context) { locationManager = (LocationManager) context.getSystemService( Context.LOCATION_SERVICE); } @Override protected void onActive() { locationManager.requestLocationUpdates... } @Override protected void onInactive() { locationManager.removeUpdates… } } sample by Google
24. ViewModelProviders.of(cntx).get(ViewModel.class) // ViewModel
25. Easy data sharing // ViewModel
26. Configuration change awareness // ViewModel
27. ViewModel#onCleared() // ViewModel
28. Presenter(ViewModel...) by Google // ViewModel
29. public class SharedViewModel extends ViewModel { private final MutableLiveData<Item> selected = new MutableLiveData<>(); public void select(Item item) { selected.setValue(item); } public LiveData<Item> getSelected() { return selected; } } public class MasterFragment extends Fragment { public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); SharedViewModel model = ViewModelProviders.of(getActivity()).get(SharedViewModel.class); itemSelector.setOnClickListener(item -> { model.select(item); }); } } public class DetailFragment extends LifecycleFragment { public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); SharedViewModel model = ViewModelProviders.of(getActivity()).get(SharedViewModel.class); model.getSelected().observe(this, { item -> // update UI }); } } sample by Google
30. ViewModel vs SavedInstanceState
31. Piece of advice from Google
32. Testing InstantTaskExecutorRule CountingTaskExecutorRule Easy mocking as with MVVMPC-like arch
33. Links to check Official guide https://developer.android.com/topic/libraries/architecture/guide.html Official samples https://github.com/googlesamples/android-architecture-components Awesome article on Medium https://medium.com/exploring-android/exploring-the-new-android-architecture-com ponents-c33b15d89c23 https://academy.realm.io/posts/360-andev-2017-yigit-boyar-android-architecture-c omponents/
34. Thanks V. Chornenkyy Skype: leo_aod Room: “Good&Co openspace”
35. Feedback https://www.surveymonkey.com/r/B6Y3WDS