Does calling a ViewModel instance reset the LiveData?

Question

In Kotlin I'm using

viewModel = ViewModelProviders.of(this).get(HomeViewModel::class.java)

To retrieve a ViewModel from the providers.

Inside my ViewModel I have something like this.

val liveChuchuData = MutableLiveData<DataChuchu>()

From my understanding this creates a final new variable of MutableLiveData right?

I remember when declaring MutableLiveDatas in ViewModel in Java, we create a function and then check if the MutableLiveData is null to only create it once. So what if I have a fragment that will also use the same ViewModel instance.

val liveChuchuData = MutableLiveData<DataChuchu>()

Will that line cause the current data to be reset, once called in a fragment?

Answer 1

Depends on what is the parent of your ViewModel. If parent is Acivity and in your Fragment you initialize your ViewModel with getActivity() instead of passing this, then you will reuse that ViewModel, but for example if you have two separate Fragments that initialize same ViewModel by passing this to ViewModelProvider then your ViewModel will have two separate instances and different data in them.

To have same data in ViewModel in two Fragments, you need to pass getActivity(); to ViewModelProvider when creating your ViewModel instance.

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That said, YES, it will cause your data to be reset if you use this when creating ViewModel.

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Hope this helps. Good luck :)