Develop Reference

List wont display properly

I am trying to display data on two different fragments from viewmodels: Recent Races and Upcoming Races. i wrote a filter function to filter the races that are yet to start and the ones that finished. Upcoming races works perfectly, when there is a change in api endpoint it removes the race from upcoming races list. but the problem is that it wont add it to recent races.
here is my code in RecentRacesViewModel
private fun getDetails() {
getRaceDetailsUseCase().onEach { result ->
when (result) {
is Resource.Success -> {
val filteredList = result.data.filter {
val time = Calendar.getInstance().time
val formatterCurrentTime = SimpleDateFormat("yyyy-MM-dd")
val formatterNow = DateTimeFormatter.ofPattern("yyyy-MM-dd")
val currentTime = formatterCurrentTime.format(time)
val dateNow = LocalDate.parse(currentTime, formatterNow)
val dateFromModel = it.date
val formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd")
val date = LocalDate.parse(dateFromModel, formatter)
dateNow >= date
}
_state1.value = Resource.Success(filteredList)
}
is Resource.Error -> {
_state1.value = Resource.Error("woops!")
}
is Resource.Loading -> {
_state1.value = Resource.Loading(true)
}
}
}.launchIn(viewModelScope)
}
thanks for help
Edit: adding the UseCase:
class RaceDetailsUseCase #Inject constructor(
private val repository: RaceResultsRepository
) {
operator fun invoke(): Flow<Resource<List<RaceDomain>>> = flow {
try {
emit(Resource.Loading(true))
val raceData = repository.GetRaceResultsRepository()
emit(Resource.Success(raceData))
} catch (e: HttpException) {
Log.d("tag", "error")
} catch (e: IOException) {
Log.d("tag", "io error")
}
}
}

How to test ViewModel + Flow

I'm doing a small project to learn flow and the latest Android features, and I'm currently facing the viewModel's testing, which I don't know if I'm performing correctly. can you help me with it?
Currently, I am using a use case to call the repository which calls a remote data source that gets from an API service a list of strings.
I have created a State to control the values in the view model:
data class StringItemsState(
val isLoading: Boolean = false,
val items: List<String> = emptyList(),
val error: String = ""
)
and the flow:
private val stringItemsState = StringtemsState()
private val _stateFlow = MutableStateFlow(stringItemsState)
val stateFlow = _stateFlow.asStateFlow()
and finally the method that performs all the logic in the viewModel:
fun fetchStringItems() {
try {
_stateFlow.value = stringItemsState.copy(isLoading = true)
viewModelScope.launch(Dispatchers.IO) {
val result = getStringItemsUseCase.execute()
if (result.isEmpty()) {
_stateFlow.value = stringItemsState
} else {
_stateFlow.value = stringItemsState.copy(items = result)
}
}
} catch (e: Exception) {
e.localizedMessage?.let {
_stateFlow.value = stringItemsState.copy(error = it)
}
}
}
I am trying to perform the test following the What / Where / Then pattern, but the result is always an empty list and the assert verification always fails:
private val stringItems = listOf<String>("A", "B", "C")
#Test
fun `get string items - not empty`() = runBlocking {
// What
coEvery {
useCase.execute()
} returns stringItems
// Where
viewModel.fetchStringItems()
// Then
assert(viewModel.stateFlow.value.items == stringItems)
coVerify(exactly = 1) { viewModel.fetchStringItems() }
}
Can someone help me and tell me if I am doing it correctly? Thanks.

Jetpack compose CircularProgressIndicator lag on api fetch

I want to display a loading indicator when I download data from the API. However, when this happens, the indicator often stops. How can I change this or what could be wrong? Basically, I fetch departure times and process them (E.g. I convert hex colors to Jetpack Compose color, or unix dates to Date type, etc.) and then load them into a list and display them.
#Composable
fun StopScreen(
unixDate: Long? = null,
stopId: String,
viewModel: MainViewModel = hiltViewModel()
) {
LaunchedEffect(Unit) {
viewModel.getArrivalsAndDeparturesForStop(
unixDate,
stopId,
false
)
}
val isLoading by remember { viewModel.isLoading }
if (!isLoading) {
//showData
} else {
LoadingView()
}
}
#Composable
fun LoadingView() {
Box(
contentAlignment = Alignment.Center,
modifier = Modifier.fillMaxSize()
) {
CircularProgressIndicator(color = MaterialTheme.colors.primary)
}
}
And the viewmodel where I process the data:
#HiltViewModel
class MainViewModel #Inject constructor(
private val mainRepository: MainRepository
) : ViewModel() {
var stopTimesList = mutableStateOf<MutableList<StopTime>>(arrayListOf())
var alertsList = mutableStateOf<MutableList<Alert>>(arrayListOf())
var loadError = mutableStateOf("")
var isLoading = mutableStateOf(false)
var isRefreshing = mutableStateOf(false)
fun getArrivalsAndDeparturesForStop(unixDate: Long? = null, stopId: String, refresh: Boolean) {
viewModelScope.launch {
if (refresh) {
isRefreshing.value = true
} else {
isLoading.value = true
}
val result = mainRepository.getArrivalsAndDeparturesForStop(stopId = stopId, time = unixDate)
when (result) {
is Resource.Success -> {
//I temporarily store the data here, so that the screen is only refreshed on reload when all the new data has arrived and loaded
var preStopTimes: MutableList<StopTime> = arrayListOf()
var preAlertsList: MutableList<Alert> = arrayListOf()
if (result.data!!.stopTimes != null && result.data!!.alerts != null) {
var count = 0
val countAll =
result.data!!.stopTimes!!.count() + result.data!!.alertIds!!.count()
if (countAll == 0) {
loadError.value = ""
isLoading.value = false
isRefreshing.value = false
}
//ALERTS
for (alert in result.data!!.data.alerts) {
preAlertsList.add(alert)
count += 1
if (count == countAll) {
stopTimesList.value = preStopTimes
alertsList.value = preAlertsList
loadError.value = ""
isLoading.value = false
isRefreshing.value = false
}
}
for (stopTime in result.data!!.stopTimes!!) {
preStopTimes.add(stopTime)
count += 1
if (count == countAll) {
stopTimesList.value = preStopTimes
alertsList.value = preAlertsList
loadError.value = ""
isLoading.value = false
isRefreshing.value = false
}
}
} else {
loadError.value = "Error"
isLoading.value = false
isRefreshing.value = false
}
}
is Resource.Error -> {
loadError.value = result.message!!
isLoading.value = false
isRefreshing.value = false
}
}
}
}
}
Repository:
#ActivityScoped
class MainRepository #Inject constructor(
private val api: MainApi
) {
suspend fun getArrivalsAndDeparturesForStop(stopId: String,time: Long? = null): Resource<ArrivalsAndDeparturesForStop> {
val response = try {
api.getArrivalsAndDeparturesForStop(
stopId,
time
)
} catch (e: Exception) { return Resource.Error(e.message!!)}
return Resource.Success(response)
}
}

My take is that your Composable recomposes way too often. Since you're updating your state within your for loops. Otherwise, it might be because your suspend method in your MainRepository is not dispatched in the right thread.
I feel you didn't yet grasp how Compose works internally (and that's fine, it's a new topic anyway). I'd recommend hoisting a unique state instead of having several mutable states for all your properties. Then build it internally in your VM to then notify the view when the state changes.
Something like this:
data class YourViewState(
val stopTimesList: List<StopTime> = emptyList(),
val alertsList: List<Alert> = emptyList(),
val isLoading: Boolean = false,
val isRefreshing: Boolean = false,
val loadError: String? = null,
)
#HiltViewModel
class MainViewModel #Inject constructor(
private val mainRepository: MainRepository
) : ViewModel() {
var viewState by mutableStateOf<YourViewState>(YourViewState())
fun getArrivalsAndDeparturesForStop(unixDate: Long? = null, stopId: String, refresh: Boolean) {
viewModelScope.launch {
viewState = if (refresh) {
viewState.copy(isRefreshing = true)
} else {
viewState.copy(isLoading = true)
}
when (val result = mainRepository.getArrivalsAndDeparturesForStop(stopId = stopId, time = unixDate)) {
is Resource.Success -> {
//I temporarily store the data here, so that the screen is only refreshed on reload when all the new data has arrived and loaded
val preStopTimes: MutableList<StopTime> = arrayListOf()
val preAlertsList: MutableList<Alert> = arrayListOf()
if (result.data!!.stopTimes != null && result.data!!.alerts != null) {
var count = 0
val countAll = result.data!!.stopTimes!!.count() + result.data!!.alertIds!!.count()
if (countAll == 0) {
viewState = viewState.copy(isLoading = false, isRefreshing = false)
}
//ALERTS
for (alert in result.data!!.data.alerts) {
preAlertsList.add(alert)
count += 1
if (count == countAll) {
break
}
}
for (stopTime in result.data!!.stopTimes!!) {
preStopTimes.add(stopTime)
count += 1
if (count == countAll) {
break
}
}
viewState = viewState.copy(isLoading = false, isRefreshing = false, stopTimesList = preStopTimes, alertsList = preAlertsList)
} else {
viewState = viewState.copy(isLoading = false, isRefreshing = false, loadError = "Error")
}
}
is Resource.Error -> {
viewState = viewState.copy(isLoading = false, isRefreshing = false, loadError = result.message!!)
}
}
}
}
}
#Composable
fun StopScreen(
unixDate: Long? = null,
stopId: String,
viewModel: MainViewModel = hiltViewModel()
) {
LaunchedEffect(Unit) {
viewModel.getArrivalsAndDeparturesForStop(
unixDate,
stopId,
false
)
}
if (viewModel.viewState.isLoading) {
LoadingView()
} else {
//showData
}
}
Note that I've made a few improvements while keeping the original structure.
EDIT:
You need to make your suspend method from your MainRepository main-safe. It's likely it runs on the main thread (caller thread) because you don't specify on which dispatcher the coroutine runs.
suspend fun getArrivalsAndDeparturesForStop(stopId: String,time: Long? = null): Resource<ArrivalsAndDeparturesForStop> = withContext(Dispatchers.IO) {
try {
api.getArrivalsAndDeparturesForStop(
stopId,
time
)
Resource.Success(response)
} catch (e: Exception) {
Resource.Error(e.message!!)
}

After 6 months I figured out the exact solution. Everything was running on the main thread when I processed the data in the ViewModel. Looking into things further, I should have used Dispatchers.Default and / or Dispatchers.IO within the functions for CPU intensive / list soring / JSON parsing tasks.
https://developer.android.com/kotlin/coroutines/coroutines-adv
suspend fun doSmg() {
withContext(Dispatchers.IO) {
//This dispatcher is optimized to perform disk or network I/O outside of the main thread. Examples include using the Room component, reading from or writing to files, and running any network operations.
}
withContext(Dispatchers.Default) {
//This dispatcher is optimized to perform CPU-intensive work outside of the main thread. Example use cases include sorting a list and parsing JSON.
}
}

Problem with state in jetpackCompose and Flow

I have a problem for now in JetpackCompose.
The problem is, when I'm collecting the Data from a flow, the value is getting fetched from firebase like there is a listener and the data's changing everytime. But tthat's not that.
I don't know what is the real problem!
FirebaseSrcNav
suspend fun getName(uid: String): Flow<Resource.Success<Any?>> = flow {
val query = userCollection.document(uid)
val snapshot = query.get().await().get("username")
emit(Resource.success(snapshot))
}
NavRepository
suspend fun getName(uid: String) = firebase.getName(uid)
HomeViewModel
fun getName(uid: String): MutableStateFlow<Any?> {
val name = MutableStateFlow<Any?>(null)
viewModelScope.launch {
navRepository.getName(uid).collect { nameState ->
when (nameState) {
is Resource.Success -> {
name.value = nameState.data
//_posts.value = state.data
loading.value = false
}
is Resource.Failure<*> -> {
Log.e(nameState.throwable, nameState.throwable)
}
}
}
}
return name
}
The probleme is in HomeScreen I think, when I'm calling the collectasState().value.
HomeScreen
val state = rememberLazyListState()
LazyColumn(
state = state,
verticalArrangement = Arrangement.spacedBy(10.dp)
) {
items(post) { post ->
//val difference = homeViewModel.getDateTime(homeViewModel.getTimestamp())
val date = homeViewModel.getDateTime(post.timeStamp!!)
val name = homeViewModel.getName(post.postAuthor_id.toString()).collectAsState().value
QuestionCard(
name = name.toString(),
date = date!!,
image = "",
text = post.postText!!,
like = 0,
response = 0,
topic = post.topic!!
)
}
}
I can't post video but if you need an image, imagine a textField where the test is alternating between "null" and "MyName" every 0.005 second.

Check official documentation.
https://developer.android.com/kotlin/flow
Flow is asynchronous
On viewModel
private val _name = MutableStateFlow<String>("")
val name: StateFlow<String>
get() = _name
fun getName(uid: String) {
viewModelScope.launch {
//asyn call
navRepository.getName(uid).collect { nameState ->
when (nameState) {
is Resource.Success -> {
name.value = nameState.data
}
is Resource.Failure<*> -> {
//manager error
Log.e(nameState.throwable, nameState.throwable)
}
}
}
}
}
on your view
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
...
lifecycleScope.launch {
viewModel.name.collect { name -> handlename
}
}
}

Androidx datastore test: Ensure that you are only creating a single instance of datastore for this file

Currently, I am writing some test for my proto datastore. The only problem I have here is that I can't call a specific function because then my test fails / crashes. I find this very confusing, because all my other functions seem to work, except resetDatastore
Here is my code:
Repository
private companion object {
private const val SHOP_FILTER_PRODUCT_DATASTORE: String = "shop_filter_product_datastore_test"
private const val SHOP_FILTER_LIST_DATASTORE: String = "shop_filter_list_datastore_test"
private const val SHOP_FILTER_BTN_DATASTORE: String = "shop_filter_btn_datastore_test"
}
private val testNonVolatileProductDataStore = context.createDataStore(
fileName = SHOP_FILTER_PRODUCT_DATASTORE,
serializer = ShopFilterProductSerializer
)
private val testNonVolatileListDataStore = context.createDataStore(
fileName = SHOP_FILTER_LIST_DATASTORE,
serializer = ShopFilterListSerializer
)
private val testNonVolatileBtnDataStore = context.createDataStore(
fileName = SHOP_FILTER_BTN_DATASTORE,
serializer = ShopFilterBtnSerializer
)
override suspend fun setValueProduct(newProduct: ShopFilterTempHolder) {
if (newProduct.id == null || newProduct.mQuery == null) return
testNonVolatileProductDataStore.updateData { preferences ->
preferences.toBuilder().apply {
positionId = newProduct.id!!
query = newProduct.mQuery
}.build()
}
}
override suspend fun setValueList(newList: ShopFilterTempHolder) {
if (newList.id == null || newList.mQuery == null) return
testNonVolatileListDataStore.updateData { preferences ->
preferences.toBuilder().apply {
positionId = newList.id!!
query = newList.mQuery
mQueryDirection = newList.mQueryDirection
}.build()
}
}
override suspend fun setShopFilterBtn(value: Boolean) {
testNonVolatileBtnDataStore.updateData { preferences ->
preferences.toBuilder().apply {
isChecked = value
}.build()
}
}
override suspend fun peekProductValue(): ShopFilterTempHolder {
val temp = shopFilterProduct.first()
return ShopFilterTempHolder(temp.positionId, temp.query)
}
override suspend fun peekListValue(): ShopFilterTempHolder {
val temp = shopFilterList.first()
return ShopFilterTempHolder(temp.positionId, temp.query, temp.mQueryDirection)
}
override suspend fun peekBtnValue(): Boolean = mappedShopFilterBtn.first()
override suspend fun resetDatastore() {
testNonVolatileProductDataStore.updateData { preferences ->
preferences.toBuilder().apply {
positionId = Constants.SHOP_FILTER_DEFAULT_PRODUCT_ID
query = Constants.SHOP_FILTER_DEFAULT_PRODUCT_QUERY
}.build()
}
testNonVolatileListDataStore.updateData { preferences ->
preferences.toBuilder().apply {
positionId = Constants.SHOP_FILTER_DEFAULT_LIST_ID
query = Constants.SHOP_FILTER_DEFAULT_LIST_QUERY
mQueryDirection = Constants.SHOP_FILTER_DEFAULT_LIST_QUERY_DIRECTION
}.build()
}
testNonVolatileBtnDataStore.updateData { preferences ->
preferences.toBuilder().apply {
isChecked = true
}.build()
}
}
Test
#Test
fun `values should be set to default`() = runBlocking {
val newBtn = false
val newList = ShopFilterTempHolder(0, "testString", 0)
val newProduct = ShopFilterTempHolder(0, "testString", 0)
shopFilterValidator.tempBtnFilterValue = newBtn
shopFilterValidator.tempListFilter = newList
shopFilterValidator.tempProductFilter = newProduct
shopFilterValidator.setNewBtnFilter()
shopFilterValidator.setNewListFilter()
shopFilterValidator.setNewProductFilter()
assertEquals(newProduct, shopFilterDataStoreRepository.peekProductValue())
assertEquals(newList, shopFilterDataStoreRepository.peekListValue())
assertEquals(newBtn, shopFilterDataStoreRepository.peekBtnValue())
shopFilterValidator.deleteAllValues()
assertEquals(defautTempProductFilter, shopFilterDataStoreRepository.peekProductValue())
assertEquals(defaultTempListFilter, shopFilterDataStoreRepository.peekListValue())
assertEquals(defaultTempBtnFilterValue, shopFilterDataStoreRepository.peekBtnValue())
}
Stacktrace
Exception in thread "DefaultDispatcher-worker-2 #coroutine#5" java.io.IOException: Unable to rename C:\Users\Censored\AppData\Local\Temp\robolectric-Method_values_should_be_set_to_default1366629743868428403\com.example.app-dataDir\files\datastore\shop_filter_product_datastore_test.tmp.This likely means that there are multiple instances of DataStore for this file. Ensure that you are only creating a single instance of datastore for this file.
at androidx.datastore.core.SingleProcessDataStore.writeData$datastore_core(SingleProcessDataStore.kt:303)
at androidx.datastore.core.SingleProcessDataStore.transformAndWrite(SingleProcessDataStore.kt:280)
at androidx.datastore.core.SingleProcessDataStore$actor$1.invokeSuspend(SingleProcessDataStore.kt:165)
(Coroutine boundary)
at kotlinx.coroutines.CompletableDeferredImpl.await(CompletableDeferred.kt:86)
at androidx.datastore.core.SingleProcessDataStore$updateData$2.invokeSuspend(SingleProcessDataStore.kt:96)
at androidx.datastore.core.SingleProcessDataStore.updateData(SingleProcessDataStore.kt:96)
at com.example.app.repository.FakeDataStoreRepositoryImpl.deleteDataStore(FakeDataStoreRepositoryImpl.kt:86)
at com.example.app.data.models.validator.ShopFilterValidator$deleteAllValues$1.invokeSuspend(ShopFilterValidator.kt:80)

not sure if that could help you, but in my case the problem occurred when running tests on Windows machine and wasn't there when switching to Linux or executing the test on the emulator instead