Android - Filter LiveData List based on Selected Item change in ViewModel

Question

I have a AndroidViewModel for one of my fragments which contains a LiveData List, and I have another property for selected item of another LiveData List. Below is an example

Answer 1

You need to switchMap over the selectedTeam, and possibly renamed "allPlayers" because that's a lie. :P

val selectedTeam = MutableLiveData<Team>()

val allTeams: LiveData<List<Team>>
    get() = repository.getAllTeams().toLiveData()

val playersOfSelectedTeam: LiveData<List<Player>>
    get() = Transformations.switchMap(selectedTeam) { team ->
         val allPlayers = repository.getAllPlayers().toLiveData()
         val players = when {
             team == null -> allPlayers
             else -> {
                 Transformations.switchMap(allPlayers) { playerList ->
                     val filteredPlayers = MutableLiveData<List<Player>>()
                     val filteredList = playerList.filter { player -> player.team == team }
                     filteredPlayers.value = filteredList
                     filteredPlayers
                 }
             }
         }
         players 
    }

Which I really hope it works as I wrote it here directly.