Live Data

To observe Live Data in general and in combination with Data Binding specifically, we can "convert" the bloc's StateStream to LiveData:

class CalculatorViewModel : ViewModel() {
    val state = toLiveData(bloc)

In an Activity we would write:

class CalculatorActivity : AppCompatActivity() {

    val bloc by getOrCreate { calculatorBloc(it) }

    val state by lazy { toLiveData(bloc) }

Note that in Activities the initialization of the state property must be lazy because the bloc is initialized lazy too. ViewModels are created lazily already and there's no need to add another lazy initialization.

The state LiveData can be bound to the layout as usual:

<TextView
    android:text="@{viewmodel.state.toString()}"/>

<!-- or -->

<TextView
    android:text="@{activity.state.toString()}"/>