I’d like to start using

ViewModel

for my state. Could anyone advise me how to adapt the https://developer.android.com/topic/libraries/architecture/viewmodel example to support the case where an argument needs to be passed into

getUsers()

and through to

loadUsers()

for it to do its job?

class MyViewModel : ViewModel() {
    private val users: MutableLiveData<List<User>> by lazy {
        MutableLiveData().also {
            loadUsers()
        }
    }

    fun getUsers(): LiveData<List<User>> {
        return users
    }

    private fun loadUsers() {
        // Do an asynchronous operation to fetch users.
    }
}

I could store the information in an instance variable from

getUsers()

and retrieve it from

loadUsers()

, but that doesn’t seem very nice. What I need to pass in is a

Context

(to access assets and the package manager). I don’t cache the Context.

I don't think this is a good idea, at least for me, your viewModel shouldn't know the context, only the business rules and the state of the app, the view can handle the assets depending on the state

Thank you, @Alan Donizete. How should I store data that should persist through the lifetime of the application even if

MainActivity

gets destroyed?

what phase of the process do you need the

Context

for? If you can keep the ViewModel working only in terms of

Context

-insensitive data you can mix in the additional asset loading at the last mile with something like a

.map {}

of the users LiveData from your example

You can inject application class for access to context and assets etc. It will not impact your testability as your can always mock the Application class. Passing application context is pretty much safe vs activity context that will leak if it is retained somewhere in your Utils/Helper or in the repo layer.

The application context often won't have the correct

Configuration

set up, so depending what kind of resources or assets you're loading, it's an easy way to get the wrong thing

I know you mentioned you wanna follow that example. But you can just have that users live data created as a normal variable of MutableLiveData type and update it when the users are loaded inside loadUsers() Some pseudo code in the VM: val users = MutableLiveData<List<User>>() fun loadUsers(myParam: Param) { viewModelScope.launch(Dispatcher.IO) { repository.loadUsers(myParam)?.let{ users.postValue(it) } } } Provided you are using coroutines and your repo returns List<User>