I don’t think there is any best practice as such recommended by android for this. I would suggest you to use the approach which uses cleaner & less boilerplate code. If you are using android data binding along with LiveData you can go with the following approach: Your POJO object would look something like this … Read more
It means that the extension in androidx is not needed anymore. Simply remove its import import androidx.lifecycle.observe. It will be actually deprecated in androidx. Read more reasoning there. EDIT: Please note the “issue” from Erik Hoogendoorn This change causes values from the observed LiveData object to be interpreted as nullable(since the converted lambda syntax is … Read more
MutableLiveData has been updated and now it has a constructor that accepts an initial value 🙂 From what I can see, the constructor is available starting from this version: implementation ‘androidx.lifecycle:lifecycle-extensions:2.1.0-alpha01′ It’s a shame they haven’t updated MediatorLiveData to reflect that, though. 2.1.0 is finally stable, so now you can actually see the new constructor … Read more
I can observe LiveData from multiple Fragments. Can I do this with Flow? If yes then how? Yes. You can do this with emit and collect. Think emit is similar to live data postValue and collect is similar to observe. Lets give an example. Repository // I just faked the weather forecast val weatherForecast = … Read more
I have introduced just one change in your code: noteViewModel = ViewModelProviders.of(this).get(NoteViewModel.class); instead of: noteViewModel = ViewModelProviders.of(getActivity()).get(NoteViewModel.class); in Fragment‘s onCreate(Bundle) methods. And now it works seamlessly. In your version you obtained a reference of NoteViewModel common to both Fragments (from Activity). ViewModel had Observer registered in previous Fragment, I think. Therefore LiveData kept reference to … Read more
At first we need to know what is the relation between MutableLivedata and MediatorLivedata to understand the difference between them. java.lang.Object ↳ android.arch.lifecycle.LiveData<T> ↳ android.arch.lifecycle.MutableLiveData<T> ↳ android.arch.lifecycle.MediatorLiveData<T> Now it is clear that MediatorLiveData is a subclass of MutableLiveData therefore MediatorLiveData can access each and every property of MutableLiveData as well as LiveData. Question no. 1 … Read more
In LiveData – Android Developer Documentation, you can see that for LiveData, setValue() & postValue() methods are not public. Whereas, in MutableLiveData – Android Developer Documentation, you can see that, MutableLiveData extends LiveData internally and also the two magic methods of LiveData is publicly available in this and they are setValue() & postValue(). setValue(): set … Read more
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 return a LiveData object. In other … Read more
There is a more convenient solution for Kotlin with extensions: fun <T> LiveData<T>.observeOnce(lifecycleOwner: LifecycleOwner, observer: Observer<T>) { observe(lifecycleOwner, object : Observer<T> { override fun onChanged(t: T?) { observer.onChanged(t) removeObserver(this) } }) } This extension permit us to do that: liveData.observeOnce(this, Observer<Password> { if (it != null) { // do something } }) So to answer … Read more
I use a Kotlin Extension Function to make it easier: fun <T> MutableLiveData<T>.notifyObserver() { this.value = this.value } Then use it in any MutableLiveData like this: fun addIssuePost(issuePost: IssuePost) { mIssuePostLiveData.value?.add(issuePost) mIssuePostLiveData.notifyObserver() }