Looking here: <https://developer.android.com/guide/fragments/communicate> ```class ListFragment : Fr...

# android

[edward]

Looking here: https://developer.android.com/guide/fragments/communicate

class ListFragment : Fragment() {
    // Using the activityViewModels() Kotlin property delegate from the
    // fragment-ktx artifact to retrieve the ViewModel in the activity scope
    private val viewModel: ItemViewModel by activityViewModels()

wtf is activityViewModels?

[Arilson José de Oliveira Júnior]

Returns a property delegate to access parent activity’s ViewModel, if factoryProducer is specified then ViewModelProvider.Factory returned by it will be used to create ViewModel first time. Otherwise, the activity’s androidx.activity.ComponentActivity.getDefaultViewModelProviderFactory will be used.

[Arilson José de Oliveira Júnior]

so, activityViewModels() is a delegation used to create or access an instance of ViewModel by the lazy way

[Arilson José de Oliveira Júnior]

in this case, the Activity’s ViewModel was instantiated here:

[Arilson José de Oliveira Júnior]

Screen Shot 2022-01-26 at 18.02.47.png

[edward]

@Arilson José de Oliveira Júnior Thanks! I think I get it.

[Arilson José de Oliveira Júnior]

Good! It’s common instantiate ViewModel with viewModel() or sharedViewModel() delegate. Read something about that.

[zsmb]

See also the official docs for activityViewModels and `viewModels`:

https://developer.android.com/reference/kotlin/androidx/fragment/app/package-summary#(androidx.fragment.app.Fragmen[…]tyViewModels(kotlin.Function0)

https://developer.android.com/reference/kotlin/androidx/fragment/app/package-summary#(androidx.fragment.app.Fragmen[…]in.Function0,kotlin.Function0)