Develop Reference

android parallel API requests with retrofit and coroutines

I have multiple API requests that need to be called in parallel, the sequence doesn't matter.
What really matters is that all the calls should be requested to implement the UI.
The problem is that sometimes some requests don't get called which returns null values, in other words, NO GUARANTEE THAT ALL THE REQUESTS WILL BE CALLED.
I have read a lot about parallel API requests and launchers but still don't know what I have missed or what I did wrong.
here is my view model class that has all functions
#HiltViewModel
class MatchDetailsViewModel #Inject constructor(
val api:FootballApi,
val app: Application,
): AndroidViewModel(app) {
private val _matchDetailsMutableLiveData = MutableLiveData<ResponseState<FixtureById>>()
private val _matchStatsMutableLiveData = MutableLiveData<ResponseState<Stats>>()
private val _matchLineupsMutableLiveData = MutableLiveData<ResponseState<Lineups>>()
private val _matchBenchMutableLiveData = MutableLiveData<ResponseState<Bench>>()
private val _matchSideLinesMutableLiveData = MutableLiveData<ResponseState<SideLine>>()
private val _matchStandingsMutableLiveData = MutableLiveData<ResponseState<Standings>>()
val matchStandingsLiveData: LiveData<ResponseState<Standings>> = _matchStandingsMutableLiveData
val matchSideLinesLiveData: LiveData<ResponseState<SideLine>> = _matchSideLinesMutableLiveData
val matchStatsLiveData: LiveData<ResponseState<Stats>> = _matchStatsMutableLiveData
val matchDetailsLiveData: LiveData<ResponseState<FixtureById>> = _matchDetailsMutableLiveData
val matchLineupsLiveData: LiveData<ResponseState<Lineups>> = _matchLineupsMutableLiveData
val matchBenchLiveData: LiveData<ResponseState<Bench>> = _matchBenchMutableLiveData
fun callAll() {
viewModelScope.launch {
val getMatchDetailsCall = async { getMatchDetails(1582601) }
val getMatchStatsCall = async { getMatchStats(1582601) }
val getMatchLineupsCall = async { getMatchLineups(1582601) }
val getMatchBenchCall = async { getMatchBench(1582601) }
val getMatchSideLineCall = async { getMatchSideLine(15006543) }
val getMatchStandingsCall = async { getMatchStandings(12880) }
try {
getMatchDetailsCall.await()
getMatchStatsCall.await()
getMatchLineupsCall.await()
getMatchBenchCall.await()
getMatchSideLineCall.await()
getMatchStandingsCall.await()
}
catch (_: Exception){}
}
}
suspend fun getMatchStandings(seasonId: Int) = viewModelScope.launch(Dispatchers.IO) {
_matchStandingsMutableLiveData.postValue(ResponseState.Loading())
try {
val response = api.getMatchStandings(seasonId = seasonId)
Log.i("getMatchStanding()", response.body().toString())
_matchStandingsMutableLiveData.postValue(ResponseState.Success(response.body()!!))
}
catch (exception: Exception) {
Log.e("getMatchStanding()", exception.toString())
}
}
suspend fun getMatchSideLine(id: Int) = viewModelScope.launch(Dispatchers.IO) {
_matchSideLinesMutableLiveData.postValue(ResponseState.Loading())
try {
val response = api.getMatchSideLines(id = id)
Log.i("getMatchSideline()", response.body().toString())
_matchSideLinesMutableLiveData.postValue(ResponseState.Success(response.body()!!))
} catch (exception: Exception) {
Log.e("getMatchSideline()", exception.toString())
}
}
fun getMatchDetails(id: Int) = viewModelScope.launch(Dispatchers.IO) {
_matchDetailsMutableLiveData.postValue(ResponseState.Loading())
try {
val response = api.getMatchDetails(id = id)
Log.i("getMatchDetails()", response.body().toString())
_matchDetailsMutableLiveData.postValue(ResponseState.Success(response.body()!!))
} catch (exception: Exception) {
Log.e("getMatchDetails()", exception.toString())
}
}
suspend fun getMatchStats(id: Int) = viewModelScope.launch(Dispatchers.IO) {
_matchStatsMutableLiveData.postValue(ResponseState.Loading())
try {
val response = api.getMatchStats(id = id)
Log.i("getMatchStats()", response.body().toString())
_matchStatsMutableLiveData.postValue(ResponseState.Success(response.body()!!))
} catch (exception: Exception) {
Log.e("getMatchStats()", exception.toString())
}
}
suspend fun getMatchLineups(id: Int = 6) = viewModelScope.launch(Dispatchers.IO) {
_matchLineupsMutableLiveData.postValue(ResponseState.Loading())
try {
val response = api.getMatchLineups(id = id)
Log.i("getMatchLineups()", response.body().toString())
_matchLineupsMutableLiveData.postValue(ResponseState.Success(response.body()!!))
} catch (exception: Exception) {
Log.e("getMatchLineups()", exception.toString())
}
}
suspend fun getMatchBench(id: Int) = viewModelScope.launch(Dispatchers.IO) {
_matchBenchMutableLiveData.postValue(ResponseState.Loading())
try {
val response = api.getMatchBench(id = id)
Log.i("getMatchBench()", response.body().toString())
_matchBenchMutableLiveData.postValue(ResponseState.Success(response.body()!!))
} catch (exception: Exception) {
Log.e("getMatchBench()", exception.toString())
}
}
}
And here's my call in activity class
lifecycleScope.launch(Dispatchers.IO) {
matchDetailsViewModel.callAll()
}

Firebase Auth with Kotlin Flow

I am learning clean architecture and Kotlin Flow. I want to check is user mail exists in the Firebase Auth base. However, when I threw an error to the flow function, app is crash.
CheckUserUseCase.kt
class CheckUserUseCase #Inject constructor(private val repository: SignInRepository) {
operator fun invoke(mail: String): Flow<Status<Boolean, String>> = flow {
emit(Status.Loading(data = null))
try {
repository.isUserExists(mail = mail)
emit(Status.Success(data = true))
} catch (e: Exception) {
emit(Status.Error(message = e.message, data = false))
}
}
}
SignInRepository.kt
interface SignInRepository {
suspend fun isUserExists(mail: String)
}
SignInRepositoryImpl.kt
class SignInRepositoryImpl #Inject constructor(private val firebaseUserActions: FirebaseUserActions) : SignInRepository {
override suspend fun isUserExists(mail: String) {
firebaseUserActions.isUserExists(mail = mail)
}
}
FirebaseAuthentication.kt
class FirebaseAuthentication #Inject constructor(private val auth: FirebaseAuth) : FirebaseUserActions {
override suspend fun isUserExists(mail: String){
auth.fetchSignInMethodsForEmail(mail).addOnCompleteListener { task ->
task.result.signInMethods?.let {
if (it.size != 0) Log.i("App.tag", "True.")
else throw IOException() <-- Crash point.
}
}.addOnFailureListener { e -> e.printStackTrace() }
.await()
}
}
How can I return a state to Kotlin Flow method? Thank you!

Please try the following approach:
override suspend fun isUserExists(mail: String): Status {
return try {
val result = auth.fetchSignInMethodsForEmail(mail).await()
result.signInMethods?.let {
if (it.isNotEmpty()) {
Status.Success(data = true)
} else {
Status.Error(message = "No data", data = false)
}
} ?: Status.Error(message = "No Data", data = false)
} catch (e: Exception) {
Status.Error(message = e.message, data = false)
}
}
In CheckUserUseCase class just emit the result of calling isUserExists():
emit(Status.Loading(data = null))
emit(repository.isUserExists(mail = mail))

Try
it.size != 0 && it.size != null
and
if (task.isSuccessful()) {
[...]
task.result.signInMethods?.let {
[...]
}

How to get variables out from a asynctask + try & catch block in kotlin (android studio)?

In these below two functions I am getting referrerUrl and addId. I want both of them to be fetched in onCreate but don't know how because it is in try & catch block also the getGaid() function is not running without AsyncTask.
fun getreferrUrl() {
//to install referrer client
val referrerClient = InstallReferrerClient.newBuilder(this).build()
referrerClient.startConnection(object : InstallReferrerStateListener {
override fun onInstallReferrerSetupFinished(responseCode: Int) {
when (responseCode) {
InstallReferrerResponse.OK -> {
// Connection established.
try {
val response: ReferrerDetails = referrerClient.installReferrer
val referrerUrl = response.installReferrer
// here we need referrerUrl out from this fuction
} catch (e: RemoteException) {
e.printStackTrace()
}
}
//
fun getGaid() {
AsyncTask.execute {
try {
val adInfo = AdvertisingIdClient.getAdvertisingIdInfo(this)
val myId: String = if (adInfo != null) adInfo.id else null.toString()
//here we need myId out from this fuction
} catch (e: java.lang.Exception) {...}
}
}
In onCreate we need both of those strings.
// In onCreate
val url = "http://instbng.com?device_id=$device_id&
&kd_id=$kd_id&ref=$referrerUrl&gaid=$myId"
loadUrl(url)

Without coroutines, you can put the results in properties, and create a function that uses both properties and call it from both callbacks. I renamed your get... functions to fetch... since they are asynchronous. The word get in a function name implies they are synchronous.
private var referrerUrl: String? = null
private var myId: String? = null
override fun onCreate(bundle: SavedInstanceState?) {
super.onCreate(bundle)
//...
fetchReferrerUrl()
fetchGaId()
}
// proceeds with workflow if referrerUrl and myId are both available
private fun proceedIfReady() {
val referrer = referrerUrl ?: return
val id = myId ?: return
val url = "http://instbng.com?device_id=$device_id&kd_id=$kd_id&ref=$referrer&gaid=$idd"
loadUrl(url)
}
fun fetchReferrerUrl() {
val referrerClient = InstallReferrerClient.newBuilder(this).build()
referrerClient.startConnection(object : InstallReferrerStateListener {
override fun onInstallReferrerSetupFinished(responseCode: Int) {
when (responseCode) {
InstallReferrerResponse.OK -> {
// Connection established.
try {
val response: ReferrerDetails = referrerClient.installReferrer
referrerUrl = response.installReferrer
proceedIfReady()
} catch (e: RemoteException) {
e.printStackTrace()
}
}
}
}
//... handle closed connection callback
}
}
private fun fetchGaId() {
AsyncTask.execute {
try {
val adInfo = AdvertisingIdClient.getAdvertisingIdInfo(this)
runOnUiThread { // in a Fragment use view?.post
myId = if (adInfo != null) adInfo.id else null.toString()
proceedIfReady()
}
} catch (e: java.lang.Exception) {...}
}
}

Make android MVVM, Kotlin Coroutines and Retrofit 2.6 work asynchronously

I've just finished my first Android App. It works as it should but, as you can imagine, there's a lot of spaghetti code and lack of performance. From what I've learned on Android and Kotlin language making this project (and a lot of articles/tutorials/SO answers) I'm trying to start it again from scratch to realize a better version. For now I'd like to keep it as simple as possible, just to better understand how to handle API calls with Retrofit and MVVM pattern, so no Volley/RXjava/Dagger etc.
I'm starting from the login obviously; I would like to make a post request to simply compare the credentials, wait for the response and, if positive, show a "loading screen" while fetching and processing data to show in the home page. I'm not storing any information so I have realized a singleton class that holds data as long as the app is running (btw, is there another way to do it?).
RetrofitService
private val retrofitService = Retrofit.Builder()
.addConverterFactory(
GsonConverterFactory
.create(
GsonBuilder()
.excludeFieldsWithoutExposeAnnotation()
.setLenient().setDateFormat("yyyy-MM-dd")
.create()
)
)
.addConverterFactory(RetrofitConverter.create())
.baseUrl(BASE_URL)
.build()
`object ApiObject {
val retrofitService: ApiInterface by lazy {
retrofitBuilder.create(ApiInterface::class.java) }
}
ApiInterface
interface ApiInterface {
#GET("workstation/{date}")
suspend fun getWorkstations(
#Path("date") date: Date
): List<Workstation>
#GET("reservation/{date}")
suspend fun getReservations(
#Path("date") date: Date
): List<Reservation>
#GET("user")
suspend fun getUsers(): List<User>
#GET("user/login")
suspend fun validateLoginCredentials(
#Query("username") username: String,
#Query("password") password: String
): Response<User>
ApiResponse
sealed class ApiResponse<T> {
companion object {
fun <T> create(response: Response<T>): ApiResponse<T> {
return if(response.isSuccessful) {
val body = response.body()
// Empty body
if (body == null || response.code() == 204) {
ApiSuccessEmptyResponse()
} else {
ApiSuccessResponse(body)
}
} else {
val msg = response.errorBody()?.string()
val errorMessage = if(msg.isNullOrEmpty()) {
response.message()
} else {
msg.let {
return#let JSONObject(it).getString("message")
}
}
ApiErrorResponse(errorMessage ?: "Unknown error")
}
}
}
}
class ApiSuccessResponse<T>(val data: T): ApiResponse<T>()
class ApiSuccessEmptyResponse<T>: ApiResponse<T>()
class ApiErrorResponse<T>(val errorMessage: String): ApiResponse<T>()
Repository
class Repository {
companion object {
private var instance: Repository? = null
fun getInstance(): Repository {
if (instance == null)
instance = Repository()
return instance!!
}
}
private var singletonClass = SingletonClass.getInstance()
suspend fun validateLoginCredentials(username: String, password: String) {
withContext(Dispatchers.IO) {
val result: Response<User>?
try {
result = ApiObject.retrofitService.validateLoginCredentials(username, password)
when (val response = ApiResponse.create(result)) {
is ApiSuccessResponse -> {
singletonClass.loggedUser = response.data
}
is ApiSuccessEmptyResponse -> throw Exception("Something went wrong")
is ApiErrorResponse -> throw Exception(response.errorMessage)
}
} catch (error: Exception) {
throw error
}
}
}
suspend fun getWorkstationsListFromService(date: Date) {
withContext(Dispatchers.IO) {
val workstationsListResult: List<Workstation>
try {
workstationsListResult = ApiObject.retrofitService.getWorkstations(date)
singletonClass.rWorkstationsList.postValue(workstationsListResult)
} catch (error: Exception) {
throw error
}
}
}
suspend fun getReservationsListFromService(date: Date) {
withContext(Dispatchers.IO) {
val reservationsListResult: List<Reservation>
try {
reservationsListResult = ApiObject.retrofitService.getReservations(date)
singletonClass.rReservationsList.postValue(reservationsListResult)
} catch (error: Exception) {
throw error
}
}
}
suspend fun getUsersListFromService() {
withContext(Dispatchers.IO) {
val usersListResult: List<User>
try {
usersListResult = ApiObject.retrofitService.getUsers()
singletonClass.rUsersList.postValue(usersListResult.let { usersList ->
usersList.filterNot { user -> user.username == "admin" }
.sortedWith(Comparator { x, y -> x.surname.compareTo(y.surname) })
})
} catch (error: Exception) {
throw error
}
}
}
SingletonClass
const val FAILED = 0
const val COMPLETED = 1
const val RUNNING = 2
class SingletonClass private constructor() {
companion object {
private var instance: SingletonClass? = null
fun getInstance(): SingletonClass {
if (instance == null)
instance = SingletonClass()
return instance!!
}
}
//User
var loggedUser: User? = null
//Workstations List
val rWorkstationsList = MutableLiveData<List<Workstation>>()
//Reservations List
val rReservationsList = MutableLiveData<List<Reservation>>()
//Users List
val rUsersList = MutableLiveData<List<User>>()
}
ViewModel
class ViewModel : ViewModel() {
private val singletonClass = SingletonClass.getInstance()
private val repository = Repository.getInstance()
//MutableLiveData
//Login
private val _loadingStatus = MutableLiveData<Boolean>()
val loadingStatus: LiveData<Boolean>
get() = _loadingStatus
private val _successfulAuthenticationStatus = MutableLiveData<Boolean>()
val successfulAuthenticationStatus: LiveData<Boolean>
get() = _successfulAuthenticationStatus
//Data fetch
private val _listsLoadingStatus = MutableLiveData<Int>()
val listsLoadingStatus: LiveData<Int>
get() = _listsLoadingStatus
private val _errorMessage = MutableLiveData<String>()
val errorMessage: LiveData<String>
get() = _errorMessage
fun onLoginClicked(username: String, password: String) {
launchLoginAuthentication {
repository.validateLoginCredentials(username, password)
}
}
private fun launchLoginAuthentication(block: suspend () -> Unit): Job {
return viewModelScope.launch {
try {
_loadingStatus.value = true
block()
} catch (error: Exception) {
_errorMessage.postValue(error.message)
} finally {
_loadingStatus.value = false
if (singletonClass.loggedUser != null)
_successfulAuthenticationStatus.value = true
}
}
}
fun onLoginPerformed() {
val date = Calendar.getInstance().time
launchListsFetch {
//how to start these all at the same time? Then wait until their competion
//and call the two methods below?
repository.getReservationsListFromService(date)
repository.getWorkstationsListFromService(date)
repository.getUsersListFromService()
}
}
private fun launchListsFetch(block: suspend () -> Unit): Job {
return viewModelScope.async {
try {
_listsLoadingStatus.value = RUNNING
block()
} catch (error: Exception) {
_listsLoadingStatus.value = FAILED
_errorMessage.postValue(error.message)
} finally {
//I'd like to perform these operations at the same time
prepareWorkstationsList()
prepareReservationsList()
//and, when both completed, set this value
_listsLoadingStatus.value = COMPLETED
}
}
}
fun onToastShown() {
_errorMessage.value = null
}
}
LoginActivity
class LoginActivity : AppCompatActivity() {
private val viewModel: LoginViewModel
get() = ViewModelProviders.of(this).get(LoginViewModel::class.java)
private val loadingFragment = LoadingDialogFragment()
var username = ""
var password = ""
private lateinit var loginButton: Button
lateinit var context: Context
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_login)
loginButton = findViewById(R.id.login_button)
loginButton.setOnClickListener {
username = login_username.text.toString().trim()
password = login_password.text.toString().trim()
viewModel.onLoginClicked(username, password.toMD5())
}
viewModel.loadingStatus.observe(this, Observer { value ->
value?.let { show ->
progress_bar_login.visibility = if (show) View.VISIBLE else View.GONE
}
})
viewModel.successfulAuthenticationStatus.observe(this, Observer { successfullyLogged ->
successfullyLogged?.let {
loadingFragment.setStyle(DialogFragment.STYLE_NORMAL, R.style.CustomLoadingDialogFragment)
if (successfullyLogged) {
loadingFragment.show(supportFragmentManager, "loadingFragment")
viewModel.onLoginPerformed()
} else {
login_password.text.clear()
login_password.isFocused
password = ""
}
}
})
viewModel.listsLoadingStatus.observe(this, Observer { loadingResult ->
loadingResult?.let {
when (loadingResult) {
COMPLETED -> {
val intent = Intent(this, MainActivity::class.java)
startActivity(intent)
setResult(Activity.RESULT_OK)
finish()
}
FAILED -> {
loadingFragment.changeText("Error")
loadingFragment.showProgressBar(false)
loadingFragment.showRetryButton(true)
}
}
}
})
viewModel.errorMessage.observe(this, Observer { value ->
value?.let { message ->
Toast.makeText(this, message, Toast.LENGTH_SHORT).show()
viewModel.onToastShown()
}
})
}
Basically what I'm trying to do is to send username and password, show a progress bar while waiting for the result (if successful the logged user object is returned, otherwise a toast with the error message is shown), hide the progress bar and show the loading fragment. While showing the loading fragment start 3 async network calls and wait for their completion; when the third call is completed start the methods to elaborate the data and, when both done, start the next activity.
It seems to all works just fine, but debugging I've noticed the flow (basically network calls start/wait/onCompletion) is not at all like what I've described above. There's something to fix in the ViewModel, I guess, but I can't figure out what

Unable to read data via bluetooth successfully

I'm trying to create an App which can receive data and send data to the microcontroller (ESP32). But for some reason, I'm unable to receive data from microcontroller successfully.
The app is written in Kotlin, and I already tried some examples mentioned on StackOverflow, but none of them actually works on my code.
I can successfully send data to the microcontroller via Bluetooth, but I can't receive data from Bluetooth. (The method I used in the microcontroller is just simply "ESP_BT.println("Check");"
In the code snippet, the function relates to my receiving data is called "receiveBluetooth"
class ControlActivity: AppCompatActivity() {
companion object {
val myUUID: UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB")
var myBluetoothSocket: BluetoothSocket? = null
lateinit var myProgress: ProgressDialog
lateinit var myBluetoothAdapter: BluetoothAdapter
var myIsConnected: Boolean = false
lateinit var myAddress: String
val mmInStream: InputStream? = null
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.control_layout)
myAddress = intent.getStringExtra(SelectDeviceActivity.EXTRA_ADDRESS)
ConnectToDevice(this).execute()
val btnShow = findViewById<Button>(R.id.btnShow)
var inputRPM: String
//Read in value and store it as String
btnShow.setOnClickListener{
inputRPM = receiveInput()
sendCommand(inputRPM)
}
//Read RPM from microcontroller (bluetooth)
val showCountTextView = findViewById<TextView>(R.id.textView)
btnRefresh.setOnClickListener {
//showCountTextView.text = receiveBluetooth()
receiveBluetooth(showCountTextView)
}
control_disconnect.setOnClickListener{
disconnect()
}
}
private fun receiveInput(): String {
val input = findViewById<EditText>(R.id.editText)
return input.text.toString()
}
private fun sendCommand(input: String) {
if (myBluetoothSocket != null) {
try{
myBluetoothSocket!!.outputStream.write(input.toByteArray())
} catch (e: IOException) {
e.printStackTrace()
}
}
}
private fun receiveBluetooth(input: TextView) {
val buffer = ByteArray(256)
val bytes:Int
var tmpIn: InputStream? = null
if (myBluetoothSocket != null) {
try {
tmpIn = myBluetoothSocket!!.inputStream
val mmInStream = DataInputStream(tmpIn)
bytes = mmInStream.read(buffer)
val readMessage = String(buffer, 0, bytes)
input.text = readMessage
//input.text="123"
} catch (e:IOException) {
e.printStackTrace()
}
}
}
private fun disconnect() {
if (myBluetoothSocket != null) {
try {
myBluetoothSocket!!.close()
myBluetoothSocket = null
myIsConnected = false
} catch (e: IOException) {
e.printStackTrace()
}
}
finish()
}
private class ConnectToDevice(c: Context) : AsyncTask<Void, Void, String> () {
private var connectSuccess: Boolean = true
private val context: Context
init {
this.context = c
}
override fun onPreExecute() {
super.onPreExecute()
myProgress = ProgressDialog.show(context, "Connecting", "Please wait")
}
override fun doInBackground(vararg params: Void?): String? {
try {
if (myBluetoothSocket == null || !myIsConnected) {
myBluetoothAdapter = BluetoothAdapter.getDefaultAdapter()
val device: BluetoothDevice = myBluetoothAdapter.getRemoteDevice(myAddress)
myBluetoothSocket = device.createInsecureRfcommSocketToServiceRecord(myUUID)
BluetoothAdapter.getDefaultAdapter().cancelDiscovery()
myBluetoothSocket!!.connect()
}
} catch (e: IOException) {
connectSuccess = false
e.printStackTrace()
}
//Needs be fixed
return null
}
override fun onPostExecute(result: String?) {
super.onPostExecute(result)
if (!connectSuccess) {
Log.i("data", "couldn't connect")
} else {
myIsConnected = true
}
myProgress.dismiss()
}
}
}
I expect the text will show exactly "Check", but instead, my text will only show the initial value that I assigned.

Maybe you should use a library. For me works fine RxAndroidBle library:
Gradle:
implementation "com.polidea.rxandroidble2:rxandroidble:1.8.1"
Implementation:
In my project with Android Java and ESP32 too, I read some characteristics or values with simple implementations, for example:
public void setupNotification() {
if (isConnected()) {
final Disposable disposable = connectionObservable
.flatMap(rxBleConnection -> rxBleConnection.setupNotification(charactSensorDataUuid))
.doOnNext(notificationObservable -> { notificationHasBeenSetUp(); })
.flatMap(notificationObservable -> notificationObservable)
.observeOn(AndroidSchedulers.mainThread())
.subscribe(this::onNotificationReceived, this::onNotificationSetupFailure);
compositeDisposable.add(disposable);
}
}
public void readSensorConfig(){
if (isConnected()) {
final Disposable disposable = connectionObservable
.firstOrError()
.flatMap(rxBleConnection -> rxBleConnection.readCharacteristic(charactConfigUuid))
.observeOn(AndroidSchedulers.mainThread())
.subscribe(this::onSensorConfigRead, this::onReadFailure);
compositeDisposable.add(disposable);
}
}
public void readSensorData(){
if (isConnected()) {
final Disposable disposable = connectionObservable
.firstOrError()
.flatMap(rxBleConnection -> rxBleConnection.readCharacteristic(charactSensorDataUuid))
.observeOn(AndroidSchedulers.mainThread())
.subscribe(this::onSensorDataRead, this::onReadFailure);
compositeDisposable.add(disposable);
}
}
The complete Java implementation is here:
https://github.com/kike-canaries/android-hpma115s0/blob/master/app/src/main/java/hpsaturn/pollutionreporter/common/BLEHandler.java
The migration to Kotlin should be simple, also on this library the main target is Bluetooth BLE, and they have many samples on Kotlin