android-livedata

Example ViewModel: public class NameViewModel extends ViewModel { // Create a LiveData with a String private MutableLiveData<String> mCurrentName; public MutableLiveData<String> getCurrentName() { if (mCurrentName == null) { mCurrentName = new MutableLiveData<>(); } return mCurrentName; } } Main activity: mModel = ViewModelProviders.of(this).get(NameViewModel.class); // Create the observer which updates the UI. final Observer<String> nameObserver = textView::setText; // Observe the LiveData, passing in this activity as the LifecycleOwner and the observer. mModel.getCurrentName().observe(this,

What is the difference between those 2 methods of the LiveData class? The official doc and tutorial are pretty vague on that. In the map() method the first parameter called source but in the switchMap() it called trigger . What's the rationale behind that? As per the documentation Transformations.map() Applies a function on the value stored in the LiveData object, and propagates the result downstream. Transformations.switchMap() Similar to map, applies a function to the value stored in the LiveData object and unwraps and dispatches the result downstream. The function passed to switchMap() must

this is the first time I'm trying to implement MVVM architecture, and I'm a bit confused about the correct way to make an API call. Currently, I'm just trying to make a simple query from the IGDB API, and output the name of the first item in a log. My activity is setup as follow: public class PopularGamesActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_popular_games); PopularGamesViewModel popViewModel = ViewModelProviders.of(this).get(PopularGamesViewModel.class);

I have a separate class in which I handle data fetching (specifically Firebase) and I usually return LiveData objects from it and update them asynchronously. Now I want to have the returned data stored in a ViewModel, but the problem is that in order to get said value, I need to observe the LiveData object returned from my data fetching class. The observe method required a LifecycleOwner object as the first parameter, but I obviously don't have that inside of my ViewModel and I know I am not supposed to keep a reference to the Activity/Fragment inside of the ViewModel. What should I do? In

I need to get Observer event when item is added to List of LiveData. But as far as I understand event receives only when I replace the old list with new one. For example when I do the next: list.value = mutableListOf(IssuePost(UserEntity(name, email, photoUrl), issueEntity)) Observer gets event. But when I just add item to value, Observer is silent. Could you please give an advice how I can implement what I need? Internally, LiveData keeps track of each change as a version number (simple counter stored as an int). Calling setValue() increments this version and updates any observers with the

I've been using alot of RxJava Observables converted to LiveData in my code using LiveDataReactiveStreams.fromPublisher() library. So I though of adding an extension function to the RxJava Observable to easily convert them to LiveData . These are my extension functions: fun <T> Flowable<T>.toLiveData() : LiveData<T> { return LiveDataReactiveStreams.fromPublisher(this) } fun <T> Observable<T>.toLiveData(backPressureStrategy: BackpressureStrategy) : LiveData<T> { return LiveDataReactiveStreams.fromPublisher(this.toFlowable(backPressureStrategy)) } fun <T> Single<T>.toLiveData() : LiveData<T> {