Develop Reference

How to until wait 2 parallel retrofit calls both finish?

I want to call 2 retrofit services in parallel and then do an action only when both of them finished, but I don't seem to figuer it out how.
I have a viewModel where I have defined my services:
var config= List<Configuration>
fun getClientProducts() {
getClientClientConfigUseCase
.build(this)
.executeWithError({ config ->
config = config
}, {
})
}
var therapies = List<DtoTherapy>
fun getTherapies() {
getTherapiesUseCase
.build(this)
.executeWithError({ config ->
therapies = it
}, {
})
}
And then I want to call both services in parallel in my fragment:
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
setupUi(view)
loadUserData()
viewModel.getClientProducts()
viewModel.getTherapies()
}
And when both variables config and therapies have the value do an action. But as I said maybe one service take 1 sec to respond and another 4 secs, and I want only to perfom an action when both have finished. Any help with be appreciated.
Here is the class I use to build the use case call:
abstract class SingleUseCase<T> : UseCase() {
private lateinit var single: Single<T>
private lateinit var useCaseInterface: UseCaseInterface
private var withLoader: Boolean = false
private var withErrorMessage: Boolean = false
internal abstract fun buildUseCaseSingle(): Single<T>
fun build(useCaseInterface: UseCaseInterface): SingleUseCase<T> {
this.withLoader = false
this.withErrorMessage = false
this.useCaseInterface = useCaseInterface
this.single = buildUseCaseSingle()
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.doAfterSuccess { useCaseInterface.onSuccess(it) }
return this
}
fun withLoader(): SingleUseCase<T> {
this.withLoader = true
return this
}
fun withErrorMessage(): SingleUseCase<T> {
this.withErrorMessage = true
return this
}
fun single(): Single<T> {
return this.single
}
fun execute(onSuccess: ((t: T) -> Unit)) {
useCaseInterface.onPrepareRequest(withLoader)
buildObservable(onSuccess)
}
private fun buildObservable(onSuccess: ((t: T) -> Unit)) {
disposeLast()
lastDisposable = single
.doFinally { useCaseInterface.onFinishRequest(this.withLoader) }
.subscribe(
{ onSuccess(it) },
{
useCaseInterface.onError(mapError(it), withErrorMessage)
})
lastDisposable?.let {
compositeDisposable.add(it)
}
}
fun executeWithError(onSuccess: ((success: T) -> Unit), onError: ((error: ApiError ) -> Unit)) {
useCaseInterface.onPrepareRequest(withLoader)
buildObservable(onSuccess, onError)
}
private fun buildObservable(onSuccess: ((success: T) -> Unit), onError: ((error: ApiError ) -> Unit)) {
disposeLast()
lastDisposable = single
.doFinally { useCaseInterface.onFinishRequest(this.withLoader) }
.subscribe(
{ onSuccess(it) },
{
onError(mapError(it))
useCaseInterface.onError(mapError(it), withErrorMessage)
})
lastDisposable?.let {
compositeDisposable.add(it)
}
}
private fun mapError(t: Throwable): ApiError {
return if(t is HttpException) {
val apiError = t.response()?.errorBody()?.string()
try {
ApiError (t.code(), t.response()?.errorBody()?.string(), Gson().fromJson(apiError, GenericError::class.java))
} catch(e: Exception) {
ApiError (-2, "Unkown error")
}
} else ApiError (-1, "Unkown error")
}
}
And this is a specific usecase class:
class GetClientConfigUseCase #Inject constructor(private val repository: UserRepository) :
SingleUseCase<ClientConfigResponse>() {
override fun buildUseCaseSingle(): Single<ClientConfigResponse> {
return repository.getUserConfig()
}
}

I guess you need zip operation. With zip operation you can have a result of two observable in one place when both of them received data.
Observable<List<ClientProducts>> observable1 = ...
Observable<List<DtoTherapy>> observable2 = ...
Observable.zip(observable1, observable2, new BiFunction<List<ClientProducts>, List<DtoTherapy>, Result>() {
#Override
public Result apply(List<ClientProducts> products, List<DtoTherapy> therapies) throws Exception
{
// here you have both of your data
// do operations on products and therapies
// then return the result
return result;
}
});

How to update RecyclerView when use retrofit?

i want to update RecyclerView when item removed but i dont' have idea to solve, i try to use notifydatasetchanged() but it don't work.
API Interface
interface RetrofitService {
#GET("/")
suspend fun getAllItem() : Response<List<Item>>
#POST("/delete")
suspend fun deleteItem(#Body item :Item) : Response<Item>
class Repository
class ItemRepository(private val retrofitService: RetrofitService) {
suspend fun getAllItem() = retrofitService.getAllItem()
suspend fun deleteItem(item : Item) = retrofitService.deleteItem(item)
}
in ViewModel, i handle result by two function(handleItemResponse and handleListItemResponse)
class ItemViewModel(private val itemRepository: ItemRepository) : ViewModel() {
val itemResponse: MutableLiveData<Resource<Item>> = MutableLiveData()
val listItemResponse : MutableLiveData<Resource<List<Item>>> = MutableLiveData()
fun getItemResponse() = viewModelScope.launch {
val response : Response<List<Item>> = itemRepository.getAllItem()
withContext(Dispatchers.Main) {
listItemResponse.postValue(handleListItemResponse(response))
}
}
fun deleteItem(item: Item) = viewModelScope.launch {
val response = itemRepository.deleteItem(item)
itemResponse.postValue(handleItemResponse(response))
}
private fun handleItemResponse(response: Response<Item>): Resource<Item> {
if (response.isSuccessful) {
response.body()?.let { resultResponse ->
return Resource.Success(resultResponse)
}
}
return Resource.Error(response.message())
}
private fun handleListItemResponse(response: Response<List<Item>>): Resource<List<Item>> {
if (response.isSuccessful) {
response.body()?.let { resultResponse ->
return Resource.Success(resultResponse)
}
}
return Resource.Error(response.message())
}
}
and class Resource to logging result
sealed class Resource<T>(
val data:T?=null,
val messaage : String? = null
) {
class Success<T>(data:T) : Resource<T>(data)
class Error<T>(messaage: String,data:T? = null) : Resource<T>(data,messaage)
class Loading<T> : Resource<T>()
}
in Fragment , i use ViewModel like this
viewModel.listItemResponse.observe(viewLifecycleOwner, Observer {
when (it) {
is Resource.Success -> {
Toast.makeText(context,"All Success",Toast.LENGTH_SHORT).show()
it.data?.let { itemReponse ->
listItem = itemReponse
adapter.setNotes(listItem)
}
}
is Resource.Error -> {
it.messaage?.let { msg ->
Log.e("AAA","ERR:$msg ")
}
}
}
})
viewModel.getItemResponse()
}
in Adapter , i getList by function setNotes
fun setNotes(items:List<Item>){
this.items = items
notifyDataSetChanged()
}
and function to delete item
private val onItemDelete:(Item)->Unit ={ item ->
viewModel.itemResponse.observe(viewLifecycleOwner, Observer {
when (it) {
is Resource.Success -> {
it.data?.let {
Toast.makeText(context,"Delete successfully!",Toast.LENGTH_SHORT).show()
}
}
is Resource.Error -> {
it.messaage?.let { msg ->
Toast.makeText(context," \"ERR:$msg \"",Toast.LENGTH_SHORT).show()
}
}
}
})
viewModel.deleteItem(item)
}
My english not well , so i hope you sympathize and help me, have a nice day,everyone!
I fixed it, i put it for anyone face same my problem.
private val onItemDelete:(Int)->Unit ={ pos ->
viewModel.itemResponse.observe(viewLifecycleOwner, Observer {
when (it) {
is Resource.Success -> {
it.data?.let {
listItem.removeAt(pos)
adapter.notifyItemRemoved(pos)
}
}
is Resource.Error -> {
it.messaage?.let { msg ->
Toast.makeText(context," \"ERR:$msg \"",Toast.LENGTH_SHORT).show()
}
}
}
})
viewModel.deleteItem(listItem[pos])
}
just callback position of item then get it in fragment.

Nested Callback function with coroutines

I want to get a response from callback function async/await style of javascript using kotlin coroutines.
Here is my callback functions
offlineCatalog.findOfflineVideoById(id, object : OfflineCallback<Video> {
override fun onSuccess(video: Video?) {
video?.let {
//Return This Video
} ?: kotlin.run {
findVideoOnline(id, state)
}
}
override fun onFailure(throwable: Throwable?) {
findVideoOnline(id, state)
}
})
onlineCatalog.findVideoByID(id, object : VideoListener() {
override fun onVideo(video: Video?) {
video?.let {
//Return This Video
} ?: kotlin.run {
Log.e("Return Error")
}
}
override fun onError(errors: MutableList<CatalogError>) {
super.onError(errors)
Log.e("Return Error")
}
})
I want to call function that will return video object from OfflineCatalog if error in OfflineCatalog then search from OnlineCatalog.
such as
try{
val video:Video? = getVideo(id:String)
//do something
}catch(throwable:Throwable){
Log.e("Video not found")
}
Update: My Implementation
this is what I came up with
suspend fun getVideo(id: String): Video? = withContext(Dispatchers.IO) {
var video = getVideoOffline(id)
video?.let { video } ?: kotlin.run { getVideoOnline(id) }
}
suspend fun getVideoOffline(id: String): Video? = suspendCancellableCoroutine { cont ->
(offlineCatalog.findOfflineVideoById(id, object : OfflineCallback<Video> {
override fun onSuccess(video: Video?) = cont.resume(video)
override fun onFailure(throwable: Throwable?) = cont.resume(null)
}))
}
suspend fun getVideoOnline(id: String): Video? = suspendCancellableCoroutine { cont ->
catalog.findVideoByID(id, object : VideoListener() {
override fun onVideo(video: Video?) = cont.resume(video)
override fun onError(errors: MutableList<CatalogError>) = cont.resume(null)
})
}
Usage-
CoroutineScope(Dispatchers.Main).launch {
getVideo(id)?.let {
//Do Something
} ?: kotlin.run{
//Video Not Found
}
}

you have to do something like this
#ExperimentalCoroutinesApi
suspend fun getVideo(id: String): Video? = coroutineScope {
val offlineVideo: Video? = suspendCancellableCoroutine { cont ->
offlineCatalog.findOfflineVideoById(id, object : OfflineCallback<Video> {
override fun onSuccess(video: Video?) {
cont.resume(video)
}
override fun onFailure(throwable: Throwable?) {
cont.resume(null)
}
})
}
offlineVideo ?: suspendCancellableCoroutine { cont ->
// offlineVideo not found so search from onlineCatalog
onlineCatalog.findVideoByID(id, object : VideoListener() {
override fun onVideo(video: Video?) {
cont.resume(video)
}
override fun onError(errors: MutableList<CatalogError>) {
super.onError(errors)
cont.resumeWithException(someException)
}
})
}
}
then you can call it as you wanted
someScope.launch {
try {
val video: Video? = getVideo(id)
//do something
} catch (throwable: Throwable) {
Log.e("Video not found")
}
}
Read more about suspendCancellableCoroutine here

How to use flow binding

I try to handle clicks on my buttons and send action to viewModel
private fun subscribeUI() {
lifecycleScope.launch {
binding.loginButton
.clicks()
.onEach { }
.map { Action.WelcomeAction.SelectLogin }
.collect { viewModel.actions.offer(it) }
binding.homeButton
.clicks()
.onEach { }
.map { Action.WelcomeAction.SelectHome }
.collect { viewModel.actions.offer(it) }
binding.registerButton
.clicks()
.onEach {}
.map { Action.WelcomeAction.SelectRegister }
.collect { viewModel.actions.offer(it) }
}
}
Only action from login button comes to my view model. How can I merge these three flows into one? Probably that's the problem there are 3 action streams to view model

private fun subscribeUI() {
merge(
binding.loginButton.clicks().map { Action.WelcomeAction.SelectLogin },
binding.homeButton.clicks().map { Action.WelcomeAction.SelectHome },
binding.registerButton.clicks().map { Action.WelcomeAction.SelectRegister }
)
.onEach { viewModel.actions.offer(it) }
.launchIn(lifecycleScope)
}

Android ViewState using RxJava or kotlin coroutines

I'm trying to learn how to use RxJava in Android, but have run into a dead end. I have the following DataSource:
object DataSource {
enum class FetchStyle {
FETCH_SUCCESS,
FETCH_EMPTY,
FETCH_ERROR
}
var relay: BehaviorRelay<FetchStyle> = BehaviorRelay.createDefault(FetchStyle.FETCH_ERROR)
fun fetchData(): Observable<DataModel> {
return relay
.map { f -> loadData(f) }
}
private fun loadData(f: FetchStyle): DataModel {
Thread.sleep(5000)
return when (f) {
FetchStyle.FETCH_SUCCESS -> DataModel("Data Loaded")
FetchStyle.FETCH_EMPTY -> DataModel(null)
FetchStyle.FETCH_ERROR -> throw IllegalStateException("Error Fetching")
}
}
}
I want to trigger an update downstream, whenever I change the value of relay, but this doesn't happen. It works when the Activity is initialized, but not when I'm updating the value. Here's my ViewModel, from where I update the value:
class MainViewModel : ViewModel() {
val fetcher: Observable<UiStateModel> = DataSource.fetchData().replay(1).autoConnect()
.map { result -> UiStateModel.from(result) }
.onErrorReturn { exception -> UiStateModel.Error(exception) }
.startWith(UiStateModel.Loading())
.subscribeOn(Schedulers.io())
.observeOn(Schedulers.io())
fun loadSuccess() {
DataSource.relay.accept(DataSource.FetchStyle.FETCH_SUCCESS)
}
fun loadEmpty() {
DataSource.relay.accept(DataSource.FetchStyle.FETCH_EMPTY)
}
fun loadError() {
DataSource.relay.accept(DataSource.FetchStyle.FETCH_ERROR)
}
}
This is the code from the Activity that does the subsciption:
model.fetcher
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe({
uiState -> mainPresenter.loadView(uiState)
})

Ended up using kotlin coroutines instead, as I was unable to re-subscribe to ConnectableObservable and start a new fetch.
Here's the code for anyone interested.
The presenter:
class MainPresenter(val view: MainView) {
private lateinit var subscription: SubscriptionReceiveChannel<UiStateModel>
fun loadSuccess(model: MainViewModel) {
model.loadStyle(DataSource.FetchStyle.FETCH_SUCCESS)
}
fun loadError(model: MainViewModel) {
model.loadStyle(DataSource.FetchStyle.FETCH_ERROR)
}
fun loadEmpty(model: MainViewModel) {
model.loadStyle(DataSource.FetchStyle.FETCH_EMPTY)
}
suspend fun subscribe(model: MainViewModel) {
subscription = model.connect()
subscription.subscribe { loadView(it) }
}
private fun loadView(uiState: UiStateModel) {
when(uiState) {
is Loading -> view.isLoading()
is Error -> view.isError(uiState.exception.localizedMessage)
is Success -> when {
uiState.result != null -> view.isSuccess(uiState.result)
else -> view.isEmpty()
}
}
}
fun unSubscribe() {
subscription.close()
}
}
inline suspend fun <E> SubscriptionReceiveChannel<E>.subscribe(action: (E) -> Unit) = consumeEach { action(it) }
The view:
...
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
launch(UI) {
mainPresenter.subscribe(model)
}
btn_load_success.setOnClickListener {
mainPresenter.loadSuccess(model)
}
btn_load_error.setOnClickListener {
mainPresenter.loadError(model)
}
btn_load_empty.setOnClickListener {
mainPresenter.loadEmpty(model)
}
}
override fun onDestroy() {
super.onDestroy()
Log.d("View", "onDestroy()")
mainPresenter.unSubscribe()
}
...
The model:
class MainViewModel : ViewModel() {
val TAG = this.javaClass.simpleName
private val stateChangeChannel = ConflatedBroadcastChannel<UiStateModel>()
init {
/** When the model is initialized we immediately start fetching data */
fetchData()
}
override fun onCleared() {
super.onCleared()
Log.d(TAG, "onCleared() called")
stateChangeChannel.close()
}
fun connect(): SubscriptionReceiveChannel<UiStateModel> {
return stateChangeChannel.openSubscription()
}
fun fetchData() = async {
stateChangeChannel.send(UiStateModel.Loading())
try {
val state = DataSource.loadData().await()
stateChangeChannel.send(UiStateModel.from(state))
} catch (e: Exception) {
Log.e("MainModel", "Exception happened when sending new state to channel: ${e.cause}")
}
}
internal fun loadStyle(style: DataSource.FetchStyle) {
DataSource.style = style
fetchData()
}
}
And here's a link to the project on github.