Issues with Retrofit and Coroutines while Migrating an Android App to Kotlin Flow
I'm having trouble with I've been struggling with this for a few days now and could really use some help. Currently developing an Android application for a client that involves migrating old Retrofit API calls to Kotlin Flow. The app originally used RxJava extensively, and now we're attempting to replace these with Flow to take advantage of better integration with the Kotlin coroutine framework. While testing, I noticed that some of the API calls occasionally return incomplete data, which causes issues in the UI. Here's an example of how I'm implementing the API calls: ```kotlin class ApiService(private val retrofit: Retrofit) { private val api = retrofit.create(MyApi::class.java) suspend fun fetchData(): Flow<DataType> { return flow { val response = api.getData() // Retrofit call emit(response) }.catch { e -> emit(DataType.Error(e)) } } } ``` I’ve tried using `flowOn(Dispatchers.IO)` to make sure the network calls are off the main thread, yet the problem persists. Additionally, I'm using `StateFlow` in the ViewModel to handle the state of the UI: ```kotlin class MyViewModel(private val apiService: ApiService) : ViewModel() { private val _data = MutableStateFlow<DataType>(DataType.Loading) val data: StateFlow<DataType> = _data init { viewModelScope.launch { apiService.fetchData().collect { result -> _data.value = result } } } } ``` Testing shows that frequently, the UI updates with an incomplete state, which I suspect could be due to the flow not completing properly. I've adjusted the API endpoint to return proper responses, but debugging sessions show that occasionally, the flow gets cancelled. Any insights on best practices for implementing Retrofit with Kotlin Flow, or strategies to handle the incomplete data issue effectively? Would love to hear what others have experienced during similar migrations. Also, I just started profiling the application with Android Profiler, and the network requests seem to spike significantly during these operations, which doesn't happen with the original RxJava setup. Any thoughts on this? For context: I'm using Kotlin on macOS. I've been using Kotlin for about a year now. I'd be grateful for any help. I'm working with Kotlin in a Docker container on Ubuntu 22.04. Hoping someone can shed some light on this.