Android ViewModel binding

AndroidViewModelBinding.kt

class MyActivity : Activity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        /* ... */
        bindData(MyViewModel())
    }

    private fun bindData(viewModel: MyViewModel) {
        // From views
        firstName.textChanges()
                .subscribe(viewModel.setFirstName)

        lastName.textChanges()
                .subscribe(viewModel.setLastName)

        // To views
        viewModel.fullName
                .subscribe(fullName.text())
    }
}


class MyViewModel {
    private val firstName = BehaviorRelay.create<CharSequence>()
    val setFirstName: Consumer<CharSequence> = firstName


    private val lastName = BehaviorRelay.create<CharSequence>()
    val setLastName: Consumer<CharSequence> = firstName

    val fullName: Observable<CharSequence> = Observable.combineLatest(firstName, lastName,
            BiFunction<CharSequence, CharSequence, CharSequence> { first, last -> "$first $last" })
}