👀 Views: 490 💬 Answers: 1 📅 Created: 2025-06-14

android kotlin retrofit coroutines Kotlin

I'm sure I'm missing something obvious here, but I'm trying to implement I'm facing a `java.lang.NullPointerException` when making a network call using Retrofit with Kotlin Coroutines in my Android app. I have set up Retrofit to fetch data from a public API, but sometimes, the API response returns null, which is causing the app to crash. My Retrofit service interface looks like this: ```kotlin interface ApiService { @GET("path/to/endpoint") suspend fun fetchData(): Response<MyDataModel> } ``` In my repository, I'm calling this service like so: ```kotlin class MyRepository(private val apiService: ApiService) { suspend fun getData(): MyDataModel? { val response = apiService.fetchData() if (response.isSuccessful) { return response.body() // This can return null } return null } } ``` In my ViewModel, I'm observing the data: ```kotlin class MyViewModel(private val repository: MyRepository) : ViewModel() { private val _data = MutableLiveData<MyDataModel>() val data: LiveData<MyDataModel> get() = _data fun loadData() { viewModelScope.launch { val result = repository.getData() _data.value = result // This line crashes when result is null } } } ``` When `fetchData()` returns a null `Response.body()`, the assignment `_data.value = result` leads to the `NullPointerException`. I tried adding a check for null before assignment like this: ```kotlin if (result != null) { _data.value = result } else { // Handle the null case gracefully } ``` However, I'm still unsure about how to handle the scenario where the API fails or returns unexpected data. Is there a best practice for managing null responses in this context? Should I throw an exception or return a default value instead? Any guidance or insights would be greatly appreciated! For reference, this is a production CLI tool. Could someone point me to the right documentation? I'm developing on Windows 10 with Kotlin. Hoping someone can shed some light on this.