NetworkOnMainThreadException when using rxandroid and mvvm design pattern - android

I have an issue with my code which is throwing NetworkOnMainThreadException. I am trying to connect to an Android app to Odoo using Android XML-RPC library.
Here is what I am doing.
class OdooServiceImpl : OdooService {
/* This is the only function doing network operation*/
override fun userAuthenticate(
host: String,
login: String,
password: String,
database: String
): Single<Int> {
val client = XMLRPCClient("$host/xmlrpc/2/common")
val result =
client.call("login", database, login, password)
return Single.just(result as Int)
}}
This class is called from a repository class.
The repository if called by the viewmodel class using rxandroid
class OdooViewModel(private val mainRepository: OdooRepository, private val context: Context) :
ViewModel() {
val host = "https://myodoo-domain.com"
private val user = MutableLiveData<OdooResource<Int>>()
private val compositeDisposable = CompositeDisposable()
init {
authUser()
}
private fun authUser(){
user.postValue(OdooResource.authConnecting(null))
compositeDisposable.add(
mainRepository.userAuthenticate(host,"mylogin","mypassword","mdb")
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe({
if (it != null) {
user.postValue(OdooResource.authSuccess(it))
} else {
user.postValue(
OdooResource.authError(
null,
msg = "Something went wring while authenticating to $host"
)
)
}
}, {
server.postValue(
OdooResource.conError(
null,
msg = "Something went wring while authenticating to $host"
)
)
})
)
}
override fun onCleared() {
super.onCleared()
compositeDisposable.dispose()
}
fun getUser(): LiveData<OdooResource<Int>> {
return user
}
}
I have called this class from my activity as follow
class OdooActivity : AppCompatActivity() {
private lateinit var odooViewModel: OdooViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_odoo)
setupViewModel()
setupObserver()
}
private fun setupObserver() {
odooViewModel.getUser().observe(this, Observer {
Log.i("TAGGG", "Tests")
when (it.status) {
OdooStatus.AUTHENTICATION_SUCCESS -> {
progressBar.visibility = View.GONE
it.data?.let { server -> textView.setText(server.toString()) }
textView.visibility = View.VISIBLE
}
OdooStatus.AUTHENTICATION -> {
progressBar.visibility = View.VISIBLE
textView.visibility = View.GONE
}
OdooStatus.AUTHENTICATION_ERROR -> {
//Handle Error
progressBar.visibility = View.GONE
Toast.makeText(this, it.message, Toast.LENGTH_LONG).show()
}
else -> {
}
}
})
}
private fun setupViewModel() {
val viewModelFactory = OdooViewModelFactory(OdooApiHelper(OdooServiceImpl()), this)
odooViewModel = ViewModelProviders.of(this, viewModelFactory).get(OdooViewModel::class.java)
}
}
When I run the app this is a the line which is throwing the error
odooViewModel = ViewModelProviders.of(this, viewModelFactory).get(OdooViewModel::class.java)
What am I missing here??

The culprit is here:
val result = client.call("login", database, login, password)
return Single.just(result as Int)
The call to generate the result is executed, when setting up the Rx chain, which happens on the main thread. You have to make sure that the network-call is done when actually subscribing (on io()). One solution could be to return a Single.fromCallable:
return Single.fromCallable { client.call("login", database, login, password) as Int }

Related

StateFlow: Cancellation of Older Emitted State After Collecting

I m relatively new in kotlin flows and I m creating the Login Module using Flows in android. I have been stuck from past few days in flows as I m collecting it in ViewModels but I m facing problem when requesting with wrong Credentials its caching all the state. After entering the right credentials the user navigate to main Activity but the instance of the MainActivity is being created with every emitted State: Example(User Enter 3 wrong Credential and 1 Right Credential: 4 Instance of MainActivity Created). So, Is there any way that I can cancel the previous emit and only show the latest request. I m using the collectLatest as well but its not working too. Below is the code.
LoginActivity
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(mViewBinding.root)
loginListener()
}
override fun onStart() {
super.onStart()
initViews()
handleNetworkChanges()
}
private fun observeLogin() {
lifecycleScope.launchWhenCreated {
mViewModel.loginCredentials.collect { state ->
when(state){
is State.Loading -> {
showLoading()
}
is State.Success -> {
Timber.d("I m in Success" + state.data)
val intent = Intent(this#LoginActivity,MainActivity::class.java)
startActivity(intent)
closeLoading()
finish()
}
is State.Error -> {
val errorResponse = gson.fromJson(state.message,LoginResponse::class.java)
showToast(errorResponse.messages)
closeLoading()
}
}
}
}
}
private fun loginListener() {
mViewBinding.neumorphButtonSignIn.setOnClickListener {
observeLogin()
phoneNumber = mViewBinding.edtPhoneNumber.text.toString()
pin = mViewBinding.oldPIN.text.toString()
if (phoneNumber.isValidPhone()) {
sendLoginCredentials(phoneNumber ,pin)
}
else {
mViewBinding.edtPhoneNumber.snack("Please Enter valid phone number") {
action("ok") {
dismiss()
}
}
}
}
}
private fun sendLoginCredentials(phoneNumber: String , pin: String) = mViewModel.postLoginCredentials("03XXXX" , "1234")
LoginViewModel
#ExperimentalCoroutinesApi
#HiltViewModel
class LoginViewModel #Inject constructor(
private val loginRepository: LoginRepository,
) : ViewModel() {
private val _loginCredentials: MutableStateFlow<State<LoginResponse>> = MutableStateFlow(State.Empty())
val loginCredentials: StateFlow<State<LoginResponse>> get() = _loginCredentials
fun postLoginCredentials(phoneNumber: String, pin: String) {
Timber.d("postLoginCredentials: $phoneNumber + $pin")
_loginCredentials.value = State.loading()
viewModelScope.launch {
loginRepository.login(LoginRequest(phoneNumber,pin))
.map { response -> State.fromResource(response) }
.collect{state -> _loginCredentials.value = state }
}
}
}
LoginRepository
class LoginRepository #Inject constructor(
private val apiInterface: APIInterface
) {
fun login(loginRequest: LoginRequest): Flow<ResponseAPI<LoginResponse>> {
return object : NetworkBoundRepository<LoginRequest, LoginResponse>() {
override suspend fun fetchFromRemote(): Response<LoginResponse> = apiInterface.createLoginRequest(
loginRequest
)
}.asFlow()
}
NetworkBoundRepository
abstract class NetworkBoundRepository<RESULT, REQUEST> {
fun asFlow() = flow<ResponseAPI<REQUEST>> {
val apiResponse = fetchFromRemote()
val remotePosts = apiResponse.body()
if (apiResponse.isSuccessful && remotePosts != null) {
emit(ResponseAPI.Success(remotePosts))
} else {
// Something went wrong! Emit Error state.
emit(ResponseAPI.Failed(apiResponse.errorBody()!!.string()))
}
}.catch { e ->
e.printStackTrace()
emit(ResponseAPI.Failed("Network error! Can't get latest posts."))
}
#MainThread
protected abstract suspend fun fetchFromRemote(): Response<REQUEST>
}
Is there any way that I can create One Instance of MainAcitivity while ignoring the older emitted Responses? Any Operator which can work. Any help in this regard is highly appreciated. Thanks.
Actually, I was calling the observeLogin() from the login click Listener which was creating this mess in my project when I move this to onCreate(). Everything works the way as intended. So, posting this for newbie that won't stuck into this.

UI is not updating while viewModel is updated in android kotlin

I am following the MVVM pattern Activity-->ViewModel ---> Repository . Repository is calling api and updated the LiveData. The value is of LiveData is also updated in ViewModel but its not reflecting on Activity. Please guide me where i am missing, Code is given below
Activity code:
class LoginWithEmailActivity : AppCompatActivity() {
private var loginViewModel: LoginViewModel? = null
private var binding: ActivityLoginWithEmailBinding? = null
private var btnLogin : Button? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
loginViewModel = ViewModelProviders.of(this).get(LoginViewModel::class.java)
binding = DataBindingUtil.setContentView(this#LoginWithEmailActivity, R.layout.activity_login_with_email)
binding!!.setLifecycleOwner(this)
binding!!.setLoginViewModel(loginViewModel)
btnLogin = findViewById(R.id.btn_login)
loginViewModel!!.servicesLiveData!!.observe(this, Observer<LoginDataModel?> { serviceSetterGetter ->
val msg = serviceSetterGetter.success
Toast.makeText(this#LoginWithEmailActivity, ""+msg, Toast.LENGTH_SHORT).show()
Log.v("///LOGIN SUCCESS////",""+msg);
})
btnLogin!!.setOnClickListener {
loginViewModel!!.getUser()
}
}
ViewModel.kt
class LoginViewModel : ViewModel() {
var servicesLiveData: MutableLiveData<LoginDataModel>? = MutableLiveData()
fun getUser() {
servicesLiveData = MainActivityRepository.getServicesApiCall()
}
}
Repository.kt
object MainActivityRepository {
val serviceSetterGetter = MutableLiveData<LoginDataModel>()
fun getServicesApiCall(): MutableLiveData<LoginDataModel> {
val params = JsonObject()
params.addProperty("email", "xyz#gmail.com")
val call: Call<LoginDataModel> = ApiClient.getClient.getPhotos(params)
call.enqueue(object : Callback<LoginDataModel> {
#RequiresApi(Build.VERSION_CODES.N)
override fun onResponse(call: Call<LoginDataModel>?, response: Response<LoginDataModel>?) {
if (response != null) {
val data = response.body()
serviceSetterGetter?.postValue(data);
}
}
override fun onFailure(call: Call<LoginDataModel>?, t: Throwable?) {
}
})
return serviceSetterGetter
}
}
You subscribe to the LiveData in onCreate
loginViewModel!!.servicesLiveData!!.observe(this, Observer<LoginDataModel?> { serviceSetterGetter ->
val msg = serviceSetterGetter.success
Toast.makeText(this#LoginWithEmailActivity, ""+msg, Toast.LENGTH_SHORT).show()
Log.v("///LOGIN SUCCESS////",""+msg);
})
but then getUser creates a new reference
fun getUser() {
servicesLiveData = MainActivityRepository.getServicesApiCall()
}
The one you are subscribed to is not the same as the getUser liveData.
If you want to keep what you have mostly the same you need to use MediatorLiveData
Or just do
getUser().observe(this, Observer<LoginDataModel?> { serviceSetterGetter ->
val msg = serviceSetterGetter.success
Toast.makeText(this#LoginWithEmailActivity, ""+msg, Toast.LENGTH_SHORT).show()
Log.v("///LOGIN SUCCESS////",""+msg);
})
fun getUser(): LiveData<LoginDataModel> {
return MainActivityRepository.getServicesApiCall()
}

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()
}

Android Room with LiveData + ViewModel Refresh Question

I have a small app I am using to try learn more about some of the newer Android components. I'm finding it difficult to find information and understand how best to do what I want.
Currently: Open app -> load data + stores in DB -> display data in list
I want to be able to query data again upon button press.
I have 2 buttons, 1 to fetch data again, 1 to delete the list data from the DB.
Problem is that it seems you cannot refresh if you are observing on an instance of LiveData, which I am. I understand that however the way I found to actually do a Network call and store in the Database returns an instance of LiveData and I am not sure how best to proceed.
Let me show you the code.
Fragment
private val viewModel: quoteViewModel by viewModels()
private lateinit var binding: FragmentHomeBinding
private lateinit var adapter: QuoteAdapter
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)
initRecyclerView()
setupRetrieveQuotesObserver()
setupDeleteDataListener()
setupFetchNewDataListener()
setupSwipeToRefresh()
}
private fun initRecyclerView() {
adapter = QuoteAdapter()
binding.recyclerView.layoutManager = LinearLayoutManager(requireContext())
binding.recyclerView.adapter = adapter
}
private fun setupDeleteDataListener() {
binding.removeQuotesButton.setOnClickListener {
viewModel.removeAllQuotes()
}
}
private fun setupFetchNewDataListener() {
binding.getQuotesButton.setOnClickListener {
viewModel.removeQuotes()
viewModel.getQuotes()
}
}
private fun setupRetrieveQuotesObserver() {
viewModel.quoteLiveDataList.observe(viewLifecycleOwner, Observer { result ->
when (result.status) {
NewResult.Status.SUCCESS -> {
result.data.let { adapter.setItems(ArrayList(result.data)) }
binding.progressBar.visibility = View.GONE
binding.swipeContainer.isRefreshing = false
}
NewResult.Status.ERROR -> {
binding.progressBar.visibility = View.GONE
Snackbar.make(binding.root, "Some error has occurred", Snackbar.LENGTH_SHORT)
.show()
}
NewResult.Status.LOADING -> {
binding.progressBar.visibility = View.VISIBLE
}
}
})
}
private fun setupSwipeToRefresh() {
binding.swipeContainer.setOnRefreshListener {
viewModel.getQuotes()
}
}
ViewModel
val quoteLiveDataList: LiveData<NewResult<List<Quote>>> = repository.quotes
fun getQuotes() = viewModelScope.launch {
repository.quotes
}
fun removeAllQuotes() = viewModelScope.launch {
repository.deleteAllQuotes()
}
Repository
val quotes = performGetOperation(
databaseQuery = { dao.getAllQuotes() },
networkCall = { remoteSource.getAllQuotes() },
saveCallResult = {
val quotesList = ArrayList<Quote>()
for (messageString in it.messages.non_personalized) {
quotesList.add(
Quote(
messageString,
FaceImageProvider().getRandomFacePicture(),
false
)
)
}
dao.insertQuotes(quotesList)
}
)
#WorkerThread
suspend fun deleteAllQuotes() = withContext(Dispatchers.IO) { dao.deleteAllQuotes() }
performGetOperation
This is a class I saw online for handling what I want to do. I think the issue stems from here as it is returning LiveData, I'm not sure how best to fix it
fun <T, A> performGetOperation(
databaseQuery: () -> LiveData<T>,
networkCall: suspend () -> NewResult<A>,
saveCallResult: suspend (A) -> Unit
): LiveData<NewResult<T>> =
liveData(Dispatchers.IO) {
emit(NewResult.loading())
val source = databaseQuery.invoke().map { NewResult.success(it) }
emitSource(source)
val responseStatus = networkCall.invoke()
if (responseStatus.status == NewResult.Status.SUCCESS) {
saveCallResult(responseStatus.data!!)
} else if (responseStatus.status == NewResult.Status.ERROR) {
emit(NewResult.error(responseStatus.message!!))
emitSource(source)
}
}
RemoteDataSource
suspend fun getQuotes() = getResult { service.getQuotes() }
getResult
protected suspend fun <T> getResult(call: suspend () -> Response<T>): NewResult<T> {
try {
val response = call.invoke()
if (response.isSuccessful) {
val body = response.body()
if (body != null) {
return NewResult.success(body)
}
}
return error("${response.code()} ${response.message()}")
} catch (e: Exception) {
return error(e.message ?: e.toString())
}
}
private fun <T> error(message: String): NewResult<T> {
Log.d("BaseDataSource", message)
return NewResult.error("Network called failed due to: $message")
}
NewResult
data class NewResult<out T>(val status: Status, val data: T?, val message: String?) {
enum class Status {
SUCCESS,
ERROR,
LOADING,
}
companion object {
fun <T> success(data: T): NewResult<T> {
return NewResult(Status.SUCCESS, data, null)
}
fun <T> error(message: String, data: T? = null): NewResult<T> {
return NewResult(Status.ERROR, data, message)
}
fun <T> loading(data: T? = null): NewResult<T> {
return NewResult(Status.LOADING, data, null)
}
}
Apologies for the very long message, but I guess I need to show all the little bits and bobs I'm using.
I think the problem is in the Fragment where I do viewModel.quoteLiveDataList.observe, as it is returning a new LiveData if it is called again. So I'm not sure how I can do another server call and update the DB and return it here.
Appreciate any help!
Thanks
Use Transformations.switchMap on a MutableLiveData to trigger your repository call like it is done here in the GithubBrowserSample project. This will allow you to implement the refresh functionality -
private val _getQuotes = MutableLiveData<Boolean>()
val quotes: LiveData<NewResult<List<Quote>>> = _getQuotes.switchMap { getQuotes ->
repository.quotes
}
fun getQuotes() {
_getQuotes.value = true
}
fun refresh() {
_getQuotes.value?.let {
_getQuotes.value = it
}
}

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.

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