Android UI (Compose & Views).

The Android view layer: Jetpack Compose, activities/fragments, ViewModel and navigation. Covers 6 sub-skills.

• Android UI (Compose & Views) · 1 of 3

  ViewModel & LiveData

  In current Android architecture guidance, which observable type does the team recommend for new ViewModel-exposed UI state instead of LiveData?

  AStateFlow from kotlinx.coroutines, collected on the UIBMutableLiveData wrapped in a Transformations.map callCRxJava BehaviorSubject bridged through LiveDataReactiveStreamsDChannel<T> exposed as a hot cold-start producer flow

• Android UI (Compose & Views) · 2 of 3

  Activities & Fragments

  How do Fragments communicate with each other in modern Android?

  ABy calling methods directly on each other through the FragmentManagerBA shared ViewModel, the Fragment Result API, or Navigation SafeArgsCThrough static singleton objects that both fragments referenceDUsing BroadcastReceivers registered in each fragment's onCreate()

• Android UI (Compose & Views) · 3 of 3

  Navigation Component

  What is the printed lifecycle state of the previous back-stack entry once the new destination has finished its transition?

  val prev = nav.currentBackStackEntrynav.navigate("detail")// after transition settles:val state = prev?.lifecycle?.currentStateprintln(state)

  AINITIALBCREATEDCRESUMEDDSTARTED