Unexpected UI Freeze When Using Coroutines with Retrofit in Android 14
I'm deploying to production and I'm working on a project and hit a roadblock. After trying multiple solutions online, I still can't figure this out. I'm working with an scenario where my app's UI freezes for a noticeable duration when making network requests via Retrofit with Kotlin Coroutines. I've set up a coroutine in a ViewModel to call a REST API, but it seems to block the UI thread. Here’s the relevant code snippet for the coroutine: ```kotlin class MyViewModel(private val repository: MyRepository) : ViewModel() { private val _data = MutableLiveData<Data>() val data: LiveData<Data> get() = _data fun fetchData() { viewModelScope.launch { try { val result = repository.getDataFromApi() _data.value = result } catch (e: Exception) { Log.e("MyViewModel", "behavior fetching data", e) } } } } ``` And here’s how I’m making the API call in the repository: ```kotlin class MyRepository(private val apiService: ApiService) { suspend fun getDataFromApi(): Data { return apiService.getData() } } ``` In my `ApiService`, I am using Retrofit with a suspend function to fetch the data: ```kotlin interface ApiService { @GET("data") suspend fun getData(): Data } ``` The question arises when I call `fetchData()` from my Fragment on a button click. While it seems to retrieve the data correctly, the UI becomes unresponsive for about 2 seconds, which is quite frustrating, especially when the network latency is low. I’ve ensured that I’m not doing any heavy operations on the main thread, and I’m using LiveData to observe the changes. I also verified that the `getData()` function is indeed marked as `suspend`. I've tried wrapping my network call in `withContext(Dispatchers.IO)` but it didn't resolve the scenario. I also checked for any long-running operations in the UI thread and couldn't find any. Is there something I'm missing or a best practice I should follow to avoid this UI freeze? Any help would be greatly appreciated! This is part of a larger service I'm building. Has anyone else encountered this? Any suggestions would be helpful. I've been using Kotlin for about a year now.