Handling Fragment Lifecycle Events with LiveData in Kotlin - Not Updating Properly
I'm stuck on something that should probably be simple. I'm relatively new to this, so bear with me. I'm encountering a frustrating issue where my `LiveData` does not seem to behave as expected in a Fragment's lifecycle. I'm using Kotlin with AndroidX and have a `ViewModel` that exposes a `LiveData<String>` representing a user name. When I navigate to this Fragment, I expect the `LiveData` to automatically update the UI with the current user name. However, the `TextView` displaying the user name remains empty until I trigger a configuration change (like rotating the device) or manually refresh the data. Here is a simplified version of my `ViewModel`: ```kotlin class UserViewModel : ViewModel() { private val _userName = MutableLiveData<String>() val userName: LiveData<String> get() = _userName fun fetchUserName() { // Simulate a network call to fetch the username _userName.value = "JohnDoe" } } ``` In my Fragment, I'm observing the `LiveData` like this: ```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?) { super.onViewCreated(view, savedInstanceState) viewModel.userName.observe(viewLifecycleOwner, Observer { name -> view.findViewById<TextView>(R.id.userNameTextView).text = name }) viewModel.fetchUserName() // Fetch username on view created } } ``` I've checked that `fetchUserName()` is called and the `LiveData` is being updated, but the UI doesn't reflect this change until a configuration change occurs. I've also tried moving the `fetchUserName()` call to `onStart()` and `onResume()` but the issue persists. I'm not getting any error messages; it just seems like the `LiveData` is not triggering the UI update as expected. Is there something I'm missing with the Fragment lifecycle or the way I'm observing the `LiveData`? Any insights would be greatly appreciated. Hoping someone can shed some light on this. I'd really appreciate any guidance on this.