Develop Reference

Preferences are neither read nor written

I am working on app settings. I am doing this in Jetpack Compose. However, when the switch button is clicked and changed to true or false, this is printed out during debug, however, the settings don't appear to change nor be saved. No way to confirm this.
Not sure of LaunchEffect{} shall be used.
AppSettings:
import kotlinx.serialization.Serializable
#Serializable
data class AppSettings(
val enableLocation: Boolean = false
)
AppSettingsSerializer:
object AppSettingsSerializer : Serializer<AppSettings> {
override val defaultValue: AppSettings
get() = AppSettings()
override suspend fun readFrom(input: InputStream): AppSettings {
return try {
Json.decodeFromString(
deserializer = AppSettings.serializer(),
string = input.readBytes().decodeToString())
} catch (e: SerializationException){
e.printStackTrace()
defaultValue
}
}
override suspend fun writeTo(t: AppSettings, output: OutputStream) {
output.write(
Json.encodeToString(
serializer = AppSettings.serializer(),
value = t)
.encodeToByteArray()
)
}
}
SettingsViewModel:
#HiltViewModel
class SettingsViewModel #Inject constructor(
val preferencesRepository: PreferencesRepository
) : ViewModel() {
var preferences by mutableStateOf(AppSettings())
private set
init {
preferencesRepository.data
.onEach { preferences = it }
.launchIn(viewModelScope)
}
inline fun updatePreferences(crossinline body: (AppSettings) -> AppSettings) {
viewModelScope.launch {
val data = body(preferences)
preferencesRepository.updateSettings(data)
}
}
}
PreferenceRepository:
class PreferencesRepository(context: Context){
private val Context.dataStore by dataStore(
fileName = "app-settings.json",
serializer = AppSettingsSerializer
)
private val appDataStore = context.dataStore
val data = appDataStore.data
suspend fun updateSettings(settings: AppSettings) {
appDataStore.updateData { settings }
}
}
Inside settings screen:
item {
SwitchPreference(
title = stringResource(R.string.location),
subtitle = AnnotatedString(stringResource(R.string.location_desc)),
checked = settings.enableLocation,
onCheckedChange = {location ->
viewModel.updatePreferences { it.copy(enableLocation = location) }
}
)
}

Firestore with StateFlow real time change is observed in repo and view model, but adapter is not being updated

As a developer one needs to adapt to change, I read somewhere it says:
If you don’t choose the right architecture for your Android project, you will have a hard time maintaining it as your codebase grows and your team expands.
I wanted to implement Clean Architecture with MVVM
My app data flow will look like this:
Model class
data class Note(
val title: String? = null,
val timestamp: String? = null
)
Dtos
data class NoteRequest(
val title: String? = null,
val timestamp: String? = null
)
and
data class NoteResponse(
val id: String? = null,
val title: String? = null,
val timestamp: String? = null
)
Repository layer is
interface INoteRepository {
fun getNoteListSuccessListener(success: (List<NoteResponse>) -> Unit)
fun deleteNoteSuccessListener(success: (List<NoteResponse>) -> Unit)
fun getNoteList()
fun deleteNoteById(noteId: String)
}
NoteRepositoryImpl is:
class NoteRepositoryImpl: INoteRepository {
private val mFirebaseFirestore = Firebase.firestore
private val mNotesCollectionReference = mFirebaseFirestore.collection(COLLECTION_NOTES)
private val noteList = mutableListOf<NoteResponse>()
private var getNoteListSuccessListener: ((List<NoteResponse>) -> Unit)? = null
private var deleteNoteSuccessListener: ((List<NoteResponse>) -> Unit)? = null
override fun getNoteListSuccessListener(success: (List<NoteResponse>) -> Unit) {
getNoteListSuccessListener = success
}
override fun deleteNoteSuccessListener(success: (List<NoteResponse>) -> Unit) {
deleteNoteSuccessListener = success
}
override fun getNoteList() {
mNotesCollectionReference
.addSnapshotListener { value, _ ->
noteList.clear()
if (value != null) {
for (item in value) {
noteList
.add(item.toNoteResponse())
}
getNoteListSuccessListener?.invoke(noteList)
}
Log.e("NOTE_REPO", "$noteList")
}
}
override fun deleteNoteById(noteId: String) {
mNotesCollectionReference.document(noteId)
.delete()
.addOnSuccessListener {
deleteNoteSuccessListener?.invoke(noteList)
}
}
}
ViewModel layer is:
interface INoteViewModel {
val noteListStateFlow: StateFlow<List<NoteResponse>>
val noteDeletedStateFlow: StateFlow<List<NoteResponse>>
fun getNoteList()
fun deleteNoteById(noteId: String)
}
NoteViewModelImpl is:
class NoteViewModelImpl: ViewModel(), INoteViewModel {
private val mNoteRepository: INoteRepository = NoteRepositoryImpl()
private val _noteListStateFlow = MutableStateFlow<List<NoteResponse>>(mutableListOf())
override val noteListStateFlow: StateFlow<List<NoteResponse>>
get() = _noteListStateFlow.asStateFlow()
private val _noteDeletedStateFlow = MutableStateFlow<List<NoteResponse>>(mutableListOf())
override val noteDeletedStateFlow: StateFlow<List<NoteResponse>>
get() = _noteDeletedStateFlow.asStateFlow()
init {
// getNoteListSuccessListener
mNoteRepository
.getNoteListSuccessListener {
viewModelScope
.launch {
_noteListStateFlow.emit(it)
Log.e("NOTE_G_VM", "$it")
}
}
// deleteNoteSuccessListener
mNoteRepository
.deleteNoteSuccessListener {
viewModelScope
.launch {
_noteDeletedStateFlow.emit(it)
Log.e("NOTE_D_VM", "$it")
}
}
}
override fun getNoteList() {
// Get all notes
mNoteRepository.getNoteList()
}
override fun deleteNoteById(noteId: String) {
mNoteRepository.deleteNoteById(noteId = noteId)
}
}
and last but not least Fragment is:
class HomeFragment : Fragment() {
private lateinit var binding: FragmentHomeBinding
private val viewModel: INoteViewModel by viewModels<NoteViewModelImpl>()
private lateinit var adapter: NoteAdapter
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View {
binding = FragmentHomeBinding.inflate(inflater, container, false)
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val recyclerView = binding.recyclerViewNotes
recyclerView.addOnScrollListener(
ExFABScrollListener(binding.fab)
)
adapter = NoteAdapter{itemView, noteId ->
if (noteId != null) {
showMenu(itemView, noteId)
}
}
recyclerView.adapter = adapter
// initView()
fetchFirestoreData()
binding.fab.setOnClickListener {
val action = HomeFragmentDirections.actionFirstFragmentToSecondFragment()
findNavController().navigate(action)
}
}
private fun fetchFirestoreData() {
// Get note list
viewModel
.getNoteList()
// Create list object
val noteList:MutableList<NoteResponse> = mutableListOf()
// Impose StateFlow
viewModel
.noteListStateFlow
.onEach { data ->
data.forEach {noteResponse ->
noteList.add(noteResponse)
adapter.submitList(noteList)
Log.e("NOTE_H_FRAG", "$noteResponse")
}
}.launchIn(viewLifecycleOwner.lifecycleScope)
}
//In the showMenu function from the previous example:
#SuppressLint("RestrictedApi")
private fun showMenu(v: View, noteId: String) {
val menuBuilder = MenuBuilder(requireContext())
SupportMenuInflater(requireContext()).inflate(R.menu.menu_note_options, menuBuilder)
menuBuilder.setCallback(object : MenuBuilder.Callback {
override fun onMenuItemSelected(menu: MenuBuilder, item: MenuItem): Boolean {
return when(item.itemId){
R.id.option_edit -> {
val action = HomeFragmentDirections.actionFirstFragmentToSecondFragment(noteId = noteId)
findNavController().navigate(action)
true
}
R.id.option_delete -> {
viewModel
.deleteNoteById(noteId = noteId)
// Create list object
val noteList:MutableList<NoteResponse> = mutableListOf()
viewModel
.noteDeletedStateFlow
.onEach {data ->
data.forEach {noteResponse ->
noteList.add(noteResponse)
adapter.submitList(noteList)
Log.e("NOTE_H_FRAG", "$noteResponse")
}
}.launchIn(viewLifecycleOwner.lifecycleScope)
true
} else -> false
}
}
override fun onMenuModeChange(menu: MenuBuilder) {}
})
val menuHelper = MenuPopupHelper(requireContext(), menuBuilder, v)
menuHelper.setForceShowIcon(true) // show icons!!!!!!!!
menuHelper.show()
}
}
With all the above logic I'm facing TWO issues
issue - 1
As mentioned here, I have added SnapshotListener on collection as:
override fun getNoteList() {
mNotesCollectionReference
.addSnapshotListener { value, _ ->
noteList.clear()
if (value != null) {
for (item in value) {
noteList
.add(item.toNoteResponse())
}
getNoteListSuccessListener?.invoke(noteList)
}
Log.e("NOTE_REPO", "$noteList")
}
}
with it if I change values of a document from Firebase Console, I get updated values in Repository and ViewModel, but list of notes is not being updated which is passed to adapter, so all the items are same.
issue - 2
If I delete any item from list/recyclerview using:
R.id.option_delete -> {
viewModel
.deleteNoteById(noteId = noteId)
// Create list object
val noteList:MutableList<NoteResponse> = mutableListOf()
viewModel
.noteDeletedStateFlow
.onEach {data ->
data.forEach {noteResponse ->
noteList.add(noteResponse)
adapter.submitList(noteList)
Log.e("NOTE_H_FRAG", "$noteResponse")
}
}.launchIn(viewLifecycleOwner.lifecycleScope)
still I get updated list(i.e new list of notes excluding deleted note) in Repository and ViewModel, but list of notes is not being updated which is passed to adapter, so all the items are same, no and exclusion of deleted item.
Question Where exactly I'm making mistake to initialize/update adapter? because ViewModel and Repository are working fine.

Make following changes:
In init{} block of NoteViewModelImpl :
// getNoteListSuccessListener
mNoteRepository
.getNoteListSuccessListener{noteResponseList ->
viewModelScope.launch{
_noteListStateFlow.emit(it.toList())
}
}
you must add .toList() if you want to emit list in StateFlow to get notified about updates, and in HomeFragment
private fun fetchFirestoreData() {
// Get note list
viewModel
.getNoteList()
// Impose StateFlow
lifecycleScope.launch {
viewModel.noteListStateFlow.collect { list ->
adapter.submitList(list.toMutableList())
}
}
}
That's it, I hope it works fine.

Try to remove additional lists of items in the fetchFirestoreData() and showMenu() (for item R.id.option_delete) methods of the HomeFragment fragment and see if it works:
// remove `val noteList:MutableList<NoteResponse>` in `fetchFirestoreData()` method
private fun fetchFirestoreData() {
...
// remove this line
val noteList:MutableList<NoteResponse> = mutableListOf()
// Impose StateFlow
viewModel
.noteListStateFlow
.onEach { data ->
adapter.submitList(data)
}.launchIn(viewLifecycleOwner.lifecycleScope)
}
And the same for the delete menu item (R.id.option_delete).

Android Kotlin coroutines create RecyclerView on fragment open with variable

As told in the title i try to create a recyclerview on fragment open with a variable.
Here is a working version without variable:
Fragment:
viewModel.lists.observe(viewLifecycleOwner) {
listAdapter.submitList(it)
}
ViewHolder:
val lists = shishaDao.getList(HARDCODED_INT).asLiveData()
As you can see, there is an hardcoded integer. This integer can hold different values, which is changing the lists value.
Here is my try with a variable:
Fragment:
viewModel.lists(title).observe(viewLifecycleOwner) {
listAdapter.submitList(it)
}
Instead of accessing a variable of the viewholder I am now wanna access a function, which needs the neccessary variable.
ViewHolder:
fun lists(title: String): LiveData<List<Tabak>> {
val nr = dao.getNr(title)
return dao.getList(nr).asLiveData()
}
The App is crashing with following error:
Cannot access database on the main thread since it may potentially lock the UI for a long period of time.
Here are also tried ways:
fun lists(title: String): LiveData<List<Tabak>> {
val nr: Int = 0
viewModelScope.launch {
nr = dao.getNr(title)
Log.e("NR", nr.toString())
}
return dao.getList(nr).asLiveData()
}
fun lists(title: String): LiveData<List<Tabak>> {
val nr: MutableLiveData<Int> = MutableLiveData(0)
viewModelScope.launch {
nr.value = dao.getNr(title)
Log.e("NR", nr.value.toString())
}
return dao.getList(nr.value!!).asLiveData()
}
Both methods do not crash. The Log.e display the right number, but the last line still uses the 0.
My actual question: How can i get thi nr value from dao.getNr(title) to use it in the last line getList(nr)?

i found a way using LiveData. This is a big way, but a useful as well.
new PreferenceManager.kt
class PreferencesManager #Inject constructor(context: Context) {
private val dataStore = context.createDataStore("user_preferences")
val preferencesFlow = dataStore.data
.catch { exception ->
if (exception is IOException) {
Log.e(TAG, "Error reading preferences", exception)
emit(emptyPreferences())
} else {
throw exception
}
}
.map { preferences ->
val choseMarke = preferences[PreferencesKeys.CHOSE_TITLE] ?: 2
FilterPreference(choseTitle)
}
suspend fun updateChoseTitle (choseTitle: Int) {
dataStore.edit { preferences ->
preferences[PreferencesKeys.CHOSE_TITLE] = choseTitle
}
}
private object PreferencesKeys {
val CHOSE_TITLE = preferencesKey<Int>("chosen_title")
}
}
Fragment.kt looks again like this
viewModel.lists.observe(viewLifecycleOwner) {
listAdapter.submitList(it)
}
And the ViewModel.kt
class ListsViewModel #ViewModelInject constructor(private val dao: Dao, private val preferencesManager: PreferencesManager, #Assisted private val state: SavedStateHandle) : ViewModel() {
val searchQuery = state.getLiveData("searchTitle", "")
val preferencesFlow = preferencesManager.preferencesFlow
...
private val listsFlow = combine(searchQuery.asFlow(), preferencesFlow) { query, filterPreference ->
Pair(query, filterPreference)
}.flatMapLatest { (_, filterPreference) ->
dao.getList(filterPreference.choseMarke)
}
I am not more trying to use the title inside of the fragment. Before opening the fragment, i need to press a button which this title, and then I already save the title (as int from the dao getNr) inside the mainActivity.
MainActivity.kt
onNavigationItemSelected(item: MenuItem): Boolean {
viewModel.onNavigationClicked(item)
}
MainViewModel.kt
fun onNavigationClicked(item: MenuItem) = viewModelScope.launch {
val choseMarkeNr = shishaDao.getMarkeNr(item.title.toString())
preferencesManager.updateChoseMarke(choseMarkeNr)
}
This way is working. :)

Android: Firebase Object is null when using kotlin flow

My problem is, that when I try to get a document out of my database, that this document aka the object is always null. I only have this problem when I use Kotlin Coroutines to get the document out of my database. Using the standard approach with listeners do work.
EmailRepository
interface EmailRepository {
suspend fun getCalibratePrice(): Flow<EmailEntity?>
suspend fun getRepairPrice(): Flow<EmailEntity?>
}
EmailRepository Implementation
class EmailRepositoryImpl #Inject constructor(private val db: FirebaseFirestore) : EmailRepository {
fun hasInternet(): Boolean {
return true
}
// This works! When using flow to write a document, the document is written!
override fun sendEmail(email: Email)= flow {
emit(EmailStatus.loading())
if (hasInternet()) {
db.collection("emails").add(email).await()
emit(EmailStatus.success(Unit))
} else {
emit(EmailStatus.failed<Unit>("No Email connection"))
}
}.catch {
emit(EmailStatus.failed(it.message.toString()))
}.flowOn(Dispatchers.Main)
// This does not work! "EmailEntity" is always null. I checked the document path!
override suspend fun getCalibratePrice(): Flow<EmailEntity?> = flow {
val result = db.collection("emailprice").document("Kalibrieren").get().await()
emit(result.toObject<EmailEntity>())
}.catch {
}.flowOn(Dispatchers.Main)
// This does not work! "EmailEntity" is always null. I checked the document path!
override suspend fun getRepairPrice(): Flow<EmailEntity?> = flow {
val result = db.collection("emailprice").document("Reparieren").get().await()
emit(result.toObject<EmailEntity>())
}.catch {
}.flowOn(Dispatchers.Main)
}
Viewmodel where I get the data
init {
viewModelScope.launch {
withContext(Dispatchers.IO) {
if (subject.value != null){
when(subject.value) {
"Test" -> {
emailRepository.getCalibratePrice().collect {
emailEntity.value = it
}
}
"Toast" -> {
emailRepository.getRepairPrice().collect {
emailEntity.value = it
}
}
}
}
}
}
}
private val emailEntity = MutableLiveData<EmailEntity?>()
private val _subject = MutableLiveData<String>()
val subject: LiveData<String> get() = _subject
Fragment
#AndroidEntryPoint
class CalibrateRepairMessageFragment() : EmailFragment<FragmentCalibrateRepairMessageBinding>(
R.layout.fragment_calibrate_repair_message,
) {
// Get current toolbar Title and send it to the next fragment.
private val toolbarText: CharSequence by lazy { toolbar_title.text }
override val viewModel: EmailViewModel by navGraphViewModels(R.id.nav_send_email) { defaultViewModelProviderFactory }
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
// Here I set the data from the MutableLiveData "subject". I don't know how to do it better
viewModel.setSubject(toolbarText.toString())
}
}
One would say, that the Firebase rules are the problems here, but that should not be the case here, because the database is open and using the listener approach does work.
I get the subject.value from my CalibrateRepairMessageFragment. When I don't check if(subject.value != null) I get a NullPointerException from my init block.
I will use the emailEntitiy only in my viewModel and not outside it.
I appreciate every help, thank you.
EDIT
This is the new way I get the data. The object is still null! I've also added Timber.d messages in my suspend functions which also never get executed therefore flow never throws an error.. With this new approach I don't get a NullPointerException anymore
private val emailEntity = liveData {
when(subject.value) {
"Test" -> emailRepository.getCalibratePrice().collect {
emit(it)
}
"Toast" -> emailRepository.getRepairPrice().collect {
emit(it)
}
// Else block is never executed, therefore "subject.value" is either Test or toast and the logic works. Still error when using flow!
else -> EmailEntity("ERROR", 0F)
}
}
I check if the emailEntity is null or not with Timber.d("EmailEntity is ${emailEntity.value}") in one of my functions.
I then set the price with val price = MutableLiveData(emailEntity.value?.basePrice ?: 1000F) but because emailentity is null the price is always 1000
EDIT 2
I have now further researched the problem and made a big step forward. When observing the emailEntity from a fragment like CalibrateRepairMessageFragment the value is no longer null.
Furthermore, when observing emailEntity the value is also not null in viewModel, but only when it is observed in one fragment! So how can I observe emailEntity from my viewModel or get the value from my repository and use it in my viewmodel?

Okay, I have solved my problem, this is the final solution:
Status class
sealed class Status<out T> {
data class Success<out T>(val data: T) : Status<T>()
class Loading<T> : Status<T>()
data class Failure<out T>(val message: String?) : Status<T>()
companion object {
fun <T> success(data: T) = Success<T>(data)
fun <T> loading() = Loading<T>()
fun <T> failed(message: String?) = Failure<T>(message)
}
}
EmailRepository
interface EmailRepository {
fun sendEmail(email: Email): Flow<Status<Unit>>
suspend fun getCalibratePrice(): Flow<Status<CalibrateRepairPricing?>>
suspend fun getRepairPrice(): Flow<Status<CalibrateRepairPricing?>>
}
EmailRepositoryImpl
class EmailRepositoryImpl (private val db: FirebaseFirestore) : EmailRepository {
fun hasInternet(): Boolean {
return true
}
override fun sendEmail(email: Email)= flow {
Timber.d("Executed Send Email Repository")
emit(Status.loading())
if (hasInternet()) {
db.collection("emails").add(email).await()
emit(Status.success(Unit))
} else {
emit(Status.failed<Unit>("No Internet connection"))
}
}.catch {
emit(Status.failed(it.message.toString()))
}.flowOn(Dispatchers.Main)
// Sends status and object to viewModel
override suspend fun getCalibratePrice(): Flow<Status<CalibrateRepairPricing?>> = flow {
emit(Status.loading())
val entity = db.collection("emailprice").document("Kalibrieren").get().await().toObject<CalibrateRepairPricing>()
emit(Status.success(entity))
}.catch {
Timber.d("Error on getCalibrate Price")
emit(Status.failed(it.message.toString()))
}
// Sends status and object to viewModel
override suspend fun getRepairPrice(): Flow<Status<CalibrateRepairPricing?>> = flow {
emit(Status.loading())
val entity = db.collection("emailprice").document("Kalibrieren").get().await().toObject<CalibrateRepairPricing>()
emit(Status.success(entity))
}.catch {
Timber.d("Error on getRepairPrice")
emit(Status.failed(it.message.toString()))
}
}
ViewModel
private lateinit var calibrateRepairPrice: CalibrateRepairPricing
private val _calirateRepairPriceErrorState = MutableLiveData<Status<Unit>>()
val calibrateRepairPriceErrorState: LiveData<Status<Unit>> get() = _calirateRepairPriceErrorState
init {
viewModelScope.launch {
when(_subject.value.toString()) {
"Toast" -> emailRepository.getCalibratePrice().collect {
when(it) {
is Status.Success -> {
calibrateRepairPrice = it.data!!
_calirateRepairPriceErrorState.postValue(Status.success(Unit))
}
is Status.Loading -> _calirateRepairPriceErrorState.postValue(Status.loading())
is Status.Failure -> _calirateRepairPriceErrorState.postValue(Status.failed(it.message))
}
}
else -> emailRepository.getRepairPrice().collect {
when(it) {
is Status.Success -> {
calibrateRepairPrice = it.data!!
_calirateRepairPriceErrorState.postValue(Status.success(Unit))
}
is Status.Loading -> _calirateRepairPriceErrorState.postValue(Status.loading())
is Status.Failure -> _calirateRepairPriceErrorState.postValue(Status.failed(it.message))
}
}
}
price.postValue(calibrateRepairPrice.head!!.basePrice)
}
}
You can now observe the status in one of your fragments (but you dont need to!)
Fragment
viewModel.calibrateRepairPriceErrorState.observe(viewLifecycleOwner) { status ->
when(status) {
is Status.Success -> requireContext().toast("Price successfully loaded")
is Status.Loading -> requireContext().toast("Price is loading")
is Status.Failure -> requireContext().toast("Error, Price could not be loaded")
}
}
This is my toast extensions function:
fun Context.toast(text: String, duration: Int = Toast.LENGTH_SHORT) {
Toast.makeText(this, text, duration).show()
}

PostValue didn't update my Observer in MVVM

I have an activity to perform rest API everytime it opened and i use MVVM pattern for this project. But with this snippet code i failed to get updated everytime i open activity. So i debug all my parameters in every line, they all fine the suspect problem might when apiService.readNewsAsync(param1,param2) execute, my postValue did not update my resulRead parameter. There were no crash here, but i got result which not updated from result (postValue). Can someone explain to me why this happened?
Here what activity looks like
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
DataBindingUtil.setContentView<ActivityReadBinding>(this,
R.layout.activity_read).apply {
this.viewModel = readViewModel
this.lifecycleOwner = this#ReadActivity
}
readViewModel.observerRead.observe(this, Observer {
val sukses = it.isSuccess
when{
sukses -> {
val data = it.data as Read
val article = data.article
//Log.d("-->", "${article.toString()}")
}
else -> {
toast("ada error ${it.msg}")
Timber.d("ERROR : ${it.msg}")
}
}
})
readViewModel.getReadNews()
}
Viewmodel
var observerRead = MutableLiveData<AppResponse>()
init {
observerRead = readRepository.observerReadNews()
}
fun getReadNews() {
// kanal and guid i fetch from intent and these value are valid
loadingVisibility = View.VISIBLE
val ok = readRepository.getReadNews(kanal!!, guid!!)
if(ok){
loadingVisibility = View.GONE
}
}
REPOSITORY
class ReadRepositoryImpl private constructor(private val newsdataDao: NewsdataDao) : ReadRepository{
override fun observerReadNews(): MutableLiveData<AppResponse> {
return newsdataDao.resultRead
}
override fun getReadNews(channel: String, guid: Int) = newsdataDao.readNews(channel, guid)
companion object{
#Volatile private var instance: ReadRepositoryImpl? = null
fun getInstance(newsdataDao: NewsdataDao) = instance ?: synchronized(this){
instance ?: ReadRepositoryImpl(newsdataDao).also {
instance = it
}
}
}
}
MODEL / DATA SOURCE
class NewsdataDao {
private val apiService = ApiClient.getClient().create(ApiService::class.java)
var resultRead = MutableLiveData<AppResponse>()
fun readNews(channel: String, guid: Int): Boolean{
GlobalScope.launch {
val response = apiService.readNewsAsync(Constants.API_TOKEN, channel, guid.toString()).await()
when{
response.isSuccessful -> {
val res = response.body()
val appRes = AppResponse(true, "ok", res!!)
resultRead.postValue(appRes)
}
else -> {
val appRes = AppResponse(false, "Error: ${response.message()}", null)
resultRead.postValue(appRes)
}
}
}
return true
}
}

Perhaps this activity is not getting stopped.
Check this out:
When you call readViewModel.getReadNews() in onCreate() your activity is created once, only if onStop is called will it be created again.