LiveData with shared preferences

Question

I have a settings screen where I am setting some values. When I set those values it gets saved in shared preferences and these values are needed in my request to the network

Answer 1

Assuming your network request is already providing you a LiveData class. For example with Retrofit and a CallAdapter like LiveDataCallAdapter.

Once you have the last observed value by either:

• Applying a listener for shared preferences OnSharedPreferenceChangeListener, as you already mentioned, to update a MutableLiveData
• Or using a SharedPreferences LiveData like rharter/SharedPreferenceLiveData.kt

Then you can apply the previous LiveData to either:

• A Transformations.switchMap as in UserViewModel.kt (related part quoted below)
• Or as parameter for MediatorLiveData addSource method.

This is the related example for the Transformations.switchMap in UserViewModel.kt:

private val _login = MutableLiveData()
val login: LiveData
    get() = _login
val repositories: LiveData>> = Transformations
    .switchMap(_login) { login ->
        if (login == null) {
            AbsentLiveData.create()
        } else {
            repoRepository.loadRepos(login)
        }
    }