A kotlin property delegate to scope any object to an android lifecycle. Blog post at https://ryanharter.com/blog/easy-android-scopes/

Scoped.kt

import androidx.lifecycle.get
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.ViewModelStore
import androidx.lifecycle.ViewModelStoreOwner

/**
 * Returns a property delegate to access the wrapped value, which will be retained for the
 * duration of the lifecycle of this [ViewModelStoreOwner].
 *
 * ```
 * class MyFragment : Fragment() {
 *   private val presenter by scoped { MyPresenter() }
 *
 *   override fun onCreate(savedInstanceState: Bundle?) {
 *     super.onCreate(savedInstanceState)
 *     presenter.models.collect {
 *       // ...
 *     }
 *   }
 * }
 * ```
 */
inline fun <reified T> ViewModelStoreOwner.scoped(noinline creator: () -> T): Lazy<T> {
  return LazyScopedValue({ viewModelStore }, { ScopeViewModel.Factory(creator) })
}

class ScopeViewModel<V>(
    val value: V
) : ViewModel() {
  class Factory<V>(val valueFactory: () -> V) : ViewModelProvider.Factory {
    @Suppress("UNCHECKED_CAST")
    override fun <T : ViewModel?> create(modelClass: Class<T>): T =
        ScopeViewModel(valueFactory()) as? T
            ?: throw java.lang.IllegalArgumentException("Unknown type")
  }
}

class LazyScopedValue<T>(
    private val storeProducer: () -> ViewModelStore,
    private val factoryProducer: () -> ViewModelProvider.Factory
) : Lazy<T> {
  private var cached: Any = NotSet

  @Suppress("UNCHECKED_CAST")
  override val value: T
    get() {
      val value = cached
      return if (value == NotSet) {
        val factory = factoryProducer()
        val store = storeProducer()
        val viewModel = ViewModelProvider(store, factory).get<ScopeViewModel<T>>()

        viewModel.value.also {
          cached = it as Any
        }
      } else {
        value as T
      }
    }

  override fun isInitialized() = cached != NotSet

  companion object {
    private val NotSet = Any()
  }
}

Yeah, this code that scopes objects to the Android Lifecycle is inherently coupled to the Android platform, since no other platform shares that lifecycle. The benefit of this is that your business logic class, a Presenter or view model (not AndeoidX View model) is no longer tightly coupled to the Android framework.

That's the code you'd want to share, anyway. There's no point sharing this code, which is glue to connect the shared code to the Framework, on other platforms, since they have their own glue code.

Awesome! Thanks for explaining @rharter