👀 Views: 49 💬 Answers: 1 📅 Created: 2025-07-18

android livedata viewmodel coroutines kotlin

I've tried everything I can think of but I'm experiencing an issue where updates to LiveData from a background thread are not consistently reflected in my UI... I'm using Android's ViewModel and LiveData from the AndroidX library, specifically version 2.3.0. The setup is quite standard; I have a ViewModel that fetches data from an API in a coroutine running on a background thread. However, when I try to push updates to a MutableLiveData, sometimes the UI doesn't refresh as expected. Here’s a simplified version of my ViewModel: ```kotlin class MyViewModel : ViewModel() { private val _data = MutableLiveData<List<MyData>>() val data: LiveData<List<MyData>> get() = _data fun fetchData() { viewModelScope.launch(Dispatchers.IO) { val result = apiService.getData() // This is a suspend function _data.postValue(result) } } } ``` In my activity, I'm observing the LiveData like this: ```kotlin class MyActivity : AppCompatActivity() { private lateinit var viewModel: MyViewModel override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) viewModel = ViewModelProvider(this).get(MyViewModel::class.java) viewModel.data.observe(this, Observer { list -> // Update UI with the new data updateUI(list) }) viewModel.fetchData() } } ``` The issue I’m facing is that occasionally the UI does not reflect the new data after `fetchData()` is called, especially when the API call returns quickly. I also noticed that if I add logging inside the observer, it shows the previous data instead of the updated data. I've already tried switching to `postValue()` and `setValue()`, but the problem persists. Additionally, I've verified that the `result` from the API is indeed updated by logging it right before posting. Is there something I may be overlooking regarding the lifecycle or threading that could cause this inconsistency? Any suggestions to ensure that my UI always receives the latest data would be greatly appreciated! For context: I'm using Kotlin on Windows. Has anyone else encountered this? I've been using Kotlin for about a year now. Hoping someone can shed some light on this.