👀 Views: 421 💬 Answers: 1 📅 Created: 2025-09-06

android kotlin architecture-components Kotlin

I'm deploying to production and Can someone help me understand I've been struggling with this for a few days now and could really use some help... I've been struggling with this for a few days now and could really use some help. While refactoring a legacy Android application to adopt more modern architecture components, I've stumbled upon some lifecycle management issues when integrating `ViewModel` and `LiveData`. The original implementation relies heavily on `Activity` and `Fragment` directly managing data and UI updates. The current goal is to decouple UI data from `Activity` using `ViewModel`, but I notice that `LiveData` observers are not behaving as expected. I created a `ViewModel` that holds user data and exposes it as `LiveData`: ```kotlin class UserViewModel : ViewModel() { private val _userData = MutableLiveData<User>() val userData: LiveData<User> = _userData fun fetchUserData(userId: String) { // Simulating a network call _userData.value = User(userId, "John Doe") } } ``` Then in my `Fragment`, I set up the observer: ```kotlin class UserFragment : Fragment() { private lateinit var viewModel: UserViewModel override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? { viewModel = ViewModelProvider(this).get(UserViewModel::class.java) return inflater.inflate(R.layout.fragment_user, container, false) } override fun onViewCreated(view: View, savedInstanceState: Bundle?) { viewModel.userData.observe(viewLifecycleOwner, Observer { user -> // Update UI with user data }) viewModel.fetchUserData("123") } } ``` Despite this setup, the UI doesn’t update as expected when `fetchUserData` is called. I’ve ensured that `observe` is tied to `viewLifecycleOwner`, yet I'm intermittently receiving the `IllegalStateException`: `Cannot invoke live data on a non-active observer.` It seems to be a timing issue related to the lifecycle. Looking into the logcat, I notice multiple calls to `fetchUserData`, possibly due to configuration changes. I considered using `SavedStateHandle` to persist the state across configuration changes, but I’m uncertain about the best practice here. Any insights on how to effectively manage the lifecycle with `LiveData` in this scenario? Are there better patterns or practices to follow to ensure data consistency while refactoring this legacy code? My development environment is Linux. Is there a better approach? This is part of a larger API I'm building. Am I missing something obvious? I appreciate any insights!