The samples in the previous article show how you can create Scenes with just the basic interfaces, but there is a lot of boilerplate setup taking place.
Fortunately, there are some base implementations that take some of this boilerplate out of your hands.

BasicScene¹

The BasicScene class is a basic abstract Scene class that provides most common functionality, such as providing a handle to the currently attached view, saving view state between subsequent attach calls, and provides a default saveInstanceState() implementation for easy state saving. It does not implement SavableScene by itself, but subclasses of BasicScene can opt in to this default implementation by explicitly implementing the 'SavableScene' interface. If we take the sample from Scene state restoration before and re-implement it using the BasicScene class, we get the following:

 1 interface MyContainer: RestorableContainer
 2 
 3 class MyScene(
 4     private val userId: String,
 5     savedState: SceneState? = null
 6 ) : BasicScene<MyContainer>(savedState),
 7     SavableScene {
 8 
 9     override fun saveInstanceState(): SceneState {
10         return super.saveInstanceState().also {
11             it["user_id"] = userId
12         }
13     }
14 
15     companion object {
16 
17         fun create(savedState: SceneState) : MyScene {
18             return MyScene(
19                 savedState["user_id"],
20                 savedState
21             )
22         }
23     }
24 }

We now only have to deal with saving and restoring our userId, and let the BaseSavableScene handle the rest.

RxScene²

The RxScene abstract class extends the BasicScene class and provides helper functions for working with Rx streams.

LifecycleScene³

The LifecycleScene abstract class extends the BasicScene class and implements the androidx.lifecycle.LifecycleOwner interface.

1: This class is available in the ext-acorn artifact.
2: This class is available in the ext-acorn-rx artifact.
3: This class is available in the ext-acorn-android-lifecycle artifact.