Develop Reference

Combining Two Flows and add them to temporary list of StateFlow(Hot Flows)

I m getting data from two End points using flows and assigning those two list to temporary list in ViewModel. For this purpose, I'm using combine function and returning result as stateFlows with stateIn operator but that's not working. Can anyone point me out where I go wrong please.
ViewModel.kt
private val _movieItem: MutableStateFlow<State<List<HomeRecyclerViewItems>>> =
MutableStateFlow(State.Loading())
val movieItems: StateFlow<State<List<HomeRecyclerViewItems>>> = _movieItem
fun getHomeItemList() {
viewModelScope.launch {
val testList: Flow<State<List<HomeRecyclerViewItems.Movie>>> =
settingsRepo.getMovieList().map {
State.fromResource(it)
}
val directorList: Flow<State<List<HomeRecyclerViewItems.Directors>>> =
settingsRepo.getDirectorList().map {
State.fromResource(it)
}
_movieItem.value = combine(testList, directorList) { testList, directorList ->
testList + directorList // This is not working as "+" Unresolve Error
}.stateIn(
viewModelScope,
SharingStarted.WhileSubscribed(5000),
State.loading<Nothing>()
) as State<List<HomeRecyclerViewItems>> // Unchecked cast: StateFlow<Any> to State<List<HomeRecyclerViewItems>>
}
Repository.kt
fun getMovieList(): Flow<ResponseAPI<List<HomeRecyclerViewItems.Movie>>> {
return object :
NetworkBoundRepository<List<HomeRecyclerViewItems.Movie>, List<HomeRecyclerViewItems.Movie>>() {
override suspend fun saveRemoteData(response: List<HomeRecyclerViewItems.Movie>) {
}
override fun fetchFromLocal() {
}
override suspend fun fetchFromRemote(): Response<List<HomeRecyclerViewItems.Movie>> =
apiInterface.getMoviesList()
}.asFlow()
}
fun getDirectorList(): Flow<ResponseAPI<List<HomeRecyclerViewItems.Directors>>> {
return object :
NetworkBoundRepository<List<HomeRecyclerViewItems.Directors>, List<HomeRecyclerViewItems.Directors>>() {
override suspend fun saveRemoteData(response: List<HomeRecyclerViewItems.Directors>) {
}
override fun fetchFromLocal() {
}
override suspend fun fetchFromRemote(): Response<List<HomeRecyclerViewItems.Directors>> =
apiInterface.getDirectorsList()
}.asFlow()
}
Network BoundRepository.kt
#ExperimentalCoroutinesApi
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 {
emit(ResponseAPI.Failed(apiResponse.errorBody()!!.string()))
}
}.catch { e ->
e.printStackTrace()
emit(ResponseAPI.Failed("Server Problem! Please try again Later. "))
}
#WorkerThread
protected abstract suspend fun saveRemoteData(response: REQUEST)
#MainThread
protected abstract fun fetchFromLocal()
#MainThread
protected abstract suspend fun fetchFromRemote(): Response<REQUEST>
}
Endpoints with Sealed Class
#GET("directors")
fun getDirectorsList(): Response<List<HomeRecyclerViewItems.Directors>>
#GET("movies")
fun getMoviesList(): Response<List<HomeRecyclerViewItems.Movie>>
sealed class HomeRecyclerViewItems {
class Title(
val id: Int,
val title: String
) : HomeRecyclerViewItems()
class Movie(
val id: Int,
val title: String,
val thumbnail: String,
val releaseDate: String
) : HomeRecyclerViewItems()
class Directors(
val id: Int,
val name: String,
val avator: String,
val movie_count: Int
) : HomeRecyclerViewItems()
}
Fragment.kt
#AndroidEntryPoint
#ExperimentalCoroutinesApi
class SettingsFragment : BaseBottomTabFragment() {
private var _binding: FragmentSettingsBinding? = null
private val binding get() = _binding!!
private val viewModel by viewModels<SettingViewModel>()
#Inject
lateinit var recyclerViewAdapter: RecyclerViewAdapter
#Inject
lateinit var bundle: Bundle
var finalList = mutableListOf<HomeRecyclerViewItems>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View {
// Inflate the layout for this fragment
_binding = FragmentSettingsBinding.inflate(layoutInflater,container,false)
val view = binding.root
binding.rvMovie.apply {
setHasFixedSize(true)
layoutManager = LinearLayoutManager(activity)
}
bundle.putString("Hello","hihg")
Toast.makeText(activity, "${bundle.getString("Hello")}", Toast.LENGTH_SHORT).show()
finalList.add(HomeRecyclerViewItems.Title(1,"hello"))
return view
}
private fun observeList() {
viewLifecycleOwner.lifecycleScope.launch {
viewLifecycleOwner.lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED){
launch {
viewModel.movieItems.collect { state ->
when(state){
is State.Loading ->{
}
is State.Success->{
if (state.data.isNotEmpty()){
recyclerViewAdapter = RecyclerViewAdapter()
binding.rvMovie.adapter = recyclerViewAdapter
recyclerViewAdapter.submitList(finalList)
}
}
is State.Error -> {
Toast.makeText(activity, "Error", Toast.LENGTH_SHORT).show()
}
else -> Unit
}
}
}
}
}
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
(activity as MainActivity).binding.ivSearch.isGone = true
viewModel.getHomeItemList()
observeList()
}
override fun onDestroyView() {
super.onDestroyView()
_binding = null
}
}
Note: I m following this tutorial simpliedCoding for api data for multirecyclerview but want to implement it with Kotlin State Flow. Any help in this regard is highly appreciated. Thanks.

Your problem is in here
val testList: Flow<State<List<HomeRecyclerViewItems.Movie>>> =
settingsRepo.getMovieList().map {
State.fromResource(it)
}
val directorList: Flow<State<List<HomeRecyclerViewItems.Directors>>> =
settingsRepo.getDirectorList().map {
State.fromResource(it)
}
_movieItem.value = combine(testList, directorList) { testList, directorList ->
testList + directorList
}
They are not returning a List<HomeRecyclerViewItems>, but a State<List<HomeRecyclerViewItems>. Maybe a better name for the variables are testsState and directorsState. After that it will be more clear why you need to unpack the values before combining the lists
_movieItem.value = combine(testsState, directorsState) { testsState, directorsState ->
val homeRecyclerViewItems = mutableListOf<HomeRecyclerViewItems>()
if (testsState is Success) homeRecyclerViewItems.add(testsState.data)
if (directorsState is Success) homeRecyclerViewItems.add(directorsState.data)
homeRecyclerViewItems
}

Update ProgressBar during a for loop using AsyncTask in Android app

I am trying to do an app where I want to update a ProgressBar in a for loop using AsyncTask. The best is to show you a pseudo code of what I am trying to do
button.setOnClickListener{
for(int i=0; i<5000; i++)
{
doSomeHeavyStuff();
UpdateProgressBarAsyncTask(i).execute()
}
}
This is what I have so far
MainActivity:
class MainActivity : AppCompatActivity() {
var progress:ProgressBar? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
progress = findViewById(R.id.progress)
val buttonStart = findViewById<TextView>(R.id.button)
var maxNumber = 5000
buttonStart.setOnClickListener{
for(i in 0 until maxNumber)
{
HeavyStuff()
ProgressTask(i,progress!!,maxNumber,this).execute()
}
}
}
internal class ProgressTask (var actual:Int, var progress: ProgressBar, var max: Int, var context: Activity): AsyncTask <Void, Int, Int>()
{
override fun onPreExecute() {
super.onPreExecute()
progress.visibility = View.VISIBLE
progress.max = max
}
override fun onProgressUpdate(vararg values: Int?) {
super.onProgressUpdate(*values)
progress.setProgress(values[0]!!)
}
override fun doInBackground(vararg params: Void?): Int? {
publishProgress(actual)
return null
}
override fun onPostExecute(result: Int?) {
super.onPostExecute(result)
progress.visibility = View.INVISIBLE
Toast.makeText(context, "Finished!", Toast.LENGTH_SHORT).show()
}
}
XML:
<ProgressBar
android:id="#+id/progress"
style="#android:style/Widget.ProgressBar.Horizontal"
android:layout_width="300dp"
android:layout_height="wrap_content"
android:layout_marginStart="24dp"
android:layout_marginLeft="24dp"
android:layout_marginTop="24dp"
android:layout_marginEnd="24dp"
android:layout_marginRight="24dp"
android:layout_marginBottom="24dp"
android:visibility="invisible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
Do I miss something here? Right now it shows ProgressBar after the HeavyStuff() is finished and thus it is not shown during the for loop. What am I missing here?
Can you guys please help me with this?
Thanks

Actually, I think that both the heavy stuff and the For Loop need to be present inside of the doBackground function (The call of heavy stuff in the main thread will freeze the UI and cause an ANR), see the code below :
const val max = 50000
class MainActivity : AppCompatActivity() {
var progress: ProgressBar? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
progress = findViewById(R.id.progress)
buttonStart.setOnClickListener {
ProgressTask(progress!!, max, this).execute()
}
}
internal class ProgressTask(
var progress: ProgressBar,
var max: Int,
var context: Activity
) : AsyncTask<Void, Int, Int>() {
override fun onPreExecute() {
super.onPreExecute()
progress.visibility = View.VISIBLE
progress.max = max
}
override fun onProgressUpdate(vararg values: Int?) {
super.onProgressUpdate(*values)
progress.setProgress(values[0]!!)
}
override fun doInBackground(vararg params: Void?): Int? {
for (i in 0 until max) {
doHeavyStuff()
publishProgress(i)
}
return null
}
override fun onPostExecute(result: Int?) {
super.onPostExecute(result)
progress.visibility = View.INVISIBLE
Toast.makeText(context, "Finished!", Toast.LENGTH_SHORT).show()
}
}
}

I would go with this approach to avoid memory leaks:
private lateinit var mTextView: WeakReference<TextView>
private lateinit var mProgressBar: WeakReference<ProgressBar>
private const val MAX = 50000
class ProgressTask(
pb: ProgressBar,
var max: Int
) : AsyncTask<Void, Int, Int>() {
init {
mProgressBar = WeakReference(pb)
}
override fun onPreExecute() {
super.onPreExecute()
mProgressBar.get()?.visibility = View.VISIBLE
mProgressBar.get()?.max = MAX
}
override fun onProgressUpdate(vararg values: Int?) {
super.onProgressUpdate(*values)
mProgressBar.get()?.progress = values[0]!!
}
override fun doInBackground(vararg p0: Void?): Int {
for (i in 0 until MAX) {
doHeavyStuff()
publishProgress(i)
}
return 1
}
override fun onPostExecute(result: Int?) {
super.onPostExecute(result)
mProgressBar.get()?.visibility = View.GONE
}
}

How to get a variable from another class in kotlin?

I want to get a variable from an activity and use it in another class.
This variable will be filled by an user in a editText that is called editTextSerie
override fun searchSeries(listener: OnDataListener) {
val retrofit = Retrofit.Builder().addConverterFactory(GsonConverterFactory.create())
.baseUrl("http://api.themoviedb.org/3/")
.build()
val client = retrofit.create(MovieDBApiInterface::class.java)
val objetoClasse1 = SearchActivity()
var nomeS = objetoClasse1.editTextSerie.text.toString().trim()
val responseCall = client.searchSeries("API_KEY", "pt-BR", nomeS)
responseCall.enqueue(object : Callback<AllSeriesResponse> {
override fun onResponse(call: Call<AllSeriesResponse>?, response1: Response<AllSeriesResponse>?) {
listener.onSuccess(response1!!.body()!!.results)
}
override fun onFailure(call: Call<AllSeriesResponse>?, t: Throwable?) {
listener.onFailure(t!!.message.toString())
}
})
}
This function "searchSeries" is from the class "Series".
I want to get the "editTextSerie" from another class called "Search Activity",
so i created the variable "nomeS" to receive the value of it.
class SearchActivity : AppCompatActivity() {
var botaoSearch: AppCompatImageButton? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_search)
botaoSearch = findViewById(R.id.btn_search)
botaoSearch?.setOnClickListener {
var nomeSerie = editTextSerie.text.toString().trim()
}
}
}
I want to receive this value (value of editTextSerie comes from the XML of SearchActivity ) and use it at responseCall with the "nomeS" variable

What is OnDataListener? Not really sure it is interface or abstract class, so I' ll write some pseudo code.
First change your function searchSeries's params to
searchSeries(text: String, listener: OnDataListener)
So in the class Series, you can get the data in your function searchSeries:
override fun searchSeries(text: String, listener: OnDataListener) {
// ...
// you can get the "text" string
}
Then edit your SearActivity's listener:
class SearchActivity : AppCompatActivity() {
var botaoSearch: AppCompatImageButton? = null
// create class "Series"
val series = Series()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_search)
botaoSearch = findViewById(R.id.btn_search)
botaoSearch?.setOnClickListener {
var nomeSeries = editTextSerie.text.toString().trim()
searchSeries(nomeSeries)
}
}
private fun searchSeries(text: String) {
series.searchSeries(text, object : OnDataListener {
override onSuccess(a0: ...) {
}
override onFailure(message: String) {
}
})
}
}
If OnDataListener is a abstract class:
series.searchSeries(text, object : OnDataListener() {
override onSuccess(a0: ...) {
}
override onFailure(message: String) {
}
})

How to set up an Async task from an activity in Kotlin

I have an activity that calls a class and runs a function in that class like so:
for (i in 0 until questions) {
droll.droolCalls(sign)
}
This can sometimes run forever as it has to generate a bunch of random numbers, so I want it to be able to run in the background. I wrote an AsyncTask that looks like this:
class MyAsync(
private val droll: CreateLayout,
private val questions: Int, private val sign:Int,
var progressBar: ProgressBar,
var layoutProgress: LinearLayout,
var layoutMain: LinearLayout
) :
AsyncTask<String, Int, CreateLayout>() {
var progress = 0
override fun doInBackground(vararg params: String?): CreateLayout {
for (i in 0 until questions) {
droll.droolCalls(sign)
}
return droll
}
override fun onProgressUpdate(vararg values: Int?) {
super.onProgressUpdate(*values)
progressBar.incrementProgressBy(progress * 10)
}
override fun onPostExecute(result: CreateLayout?) {
super.onPostExecute(result)
layoutProgress.visibility = View.GONE
layoutMain.visibility = View.VISIBLE
}
}
However, when i call the drollclass
MyAsync(droll, totalQuestions,sign, progressBar, Loading, mainLayout).execute("hello")
i get an error from other functions that require drool to run.
this one for example insert_point.addView(droll.makeTextView(numberOfQuestions - 1)) gives me a java.lang.IndexOutOfBoundsException: Index: 2, Size: 0 error because insert_point not getting the data from droll because the Async didn't run? however if i take it out of the Async the for loop our of the Async it works fine.
the whole structure looks something like this
class mainclass{
MyAsync(droll, totalQuestions,sign, progressBar, Loading, mainLayout).execute("hello")
insert_point.addView(droll.makeTextView(numberOfQuestions - 1))
class MyAsync(
private val droll: CreateLayout,
private val questions: Int, private val sign:Int,
var progressBar: ProgressBar,
var layoutProgress: LinearLayout,
var layoutMain: LinearLayout
) :
AsyncTask<String, Int, CreateLayout>() {
var progress = 0
override fun doInBackground(vararg params: String?): CreateLayout {
for (i in 0 until questions) {
droll.droolCalls(sign)
}
return droll
}
override fun onProgressUpdate(vararg values: Int?) {
super.onProgressUpdate(*values)
progressBar.incrementProgressBy(progress * 10)
}
override fun onPostExecute(result: CreateLayout?) {
super.onPostExecute(result)
layoutProgress.visibility = View.GONE
layoutMain.visibility = View.VISIBLE
}
}
}

package www.binexmining.co.`in`.binexmining.binexmining.uam.view.activity
import android.app.Activity
import android.os.AsyncTask
import android.os.Bundle
import android.support.annotation.MainThread
import kotlinx.android.synthetic.main.row_referraluser.view.*
import www.binexmining.co.`in`.binexmining.R
class AsynTaskKotlinMain : Activity()
{
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_landing)
}
override fun onResume() {
super.onResume()
MyAssyn().execute("Pre-Executing Param Put here...","Param For Doinbackgroun")
}
}
class MyAssyn : AsyncTask<Any, Any, Any>()
{
override fun onPreExecute() {
super.onPreExecute()
}
override fun doInBackground(vararg params: Any?) {
TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
}
override fun onPostExecute(result: Any?) {
super.onPostExecute(result)
}
}

AsyncTask in Android with Kotlin

How to make an API call in Android with Kotlin?
I have heard of Anko . But I want to use methods provided by Kotlin like in Android we have Asynctask for background operations.

AsyncTask is an Android API, not a language feature that is provided by Java nor Kotlin. You can just use them like this if you want:
class someTask() : AsyncTask<Void, Void, String>() {
override fun doInBackground(vararg params: Void?): String? {
// ...
}
override fun onPreExecute() {
super.onPreExecute()
// ...
}
override fun onPostExecute(result: String?) {
super.onPostExecute(result)
// ...
}
}
Anko's doAsync is not really 'provided' by Kotlin, since Anko is a library that uses language features from Kotlin to simplify long codes. Check here:
https://github.com/Kotlin/anko/blob/d5a526512b48c5cd2e3b8f6ff14b153c2337aa22/anko/library/static/commons/src/Async.kt
If you use Anko your code will be similar to this:
doAsync {
// ...
}

You can get a similar syntax to Anko's fairly easy. If you just wan't the background task you can do something like
class doAsync(val handler: () -> Unit) : AsyncTask<Void, Void, Void>() {
override fun doInBackground(vararg params: Void?): Void? {
handler()
return null
}
}
And use it like
doAsync {
yourTask()
}.execute()

Here is an example that will also allow you to update any UI or progress displayed to the user.
Async Class
class doAsync(val handler: () -> Unit) : AsyncTask<Void, Void, Void>() {
init {
execute()
}
override fun doInBackground(vararg params: Void?): Void? {
handler()
return null
}
}
Simple Usage
doAsync {
// do work here ...
myView.post({
// update UI of myView ...
})
}

AsyncTask was deprecated in API level 30. To implement similar behavior we can use Kotlin concurrency utilities (coroutines).
Create extension function on CoroutineScope:
fun <R> CoroutineScope.executeAsyncTask(
onPreExecute: () -> Unit,
doInBackground: () -> R,
onPostExecute: (R) -> Unit
) = launch {
onPreExecute()
val result = withContext(Dispatchers.IO) { // runs in background thread without blocking the Main Thread
doInBackground()
}
onPostExecute(result)
}
Now it can be used on any CoroutineScope instance, for example, in ViewModel:
class MyViewModel : ViewModel() {
fun someFun() {
viewModelScope.executeAsyncTask(onPreExecute = {
// ...
}, doInBackground = {
// ...
"Result" // send data to "onPostExecute"
}, onPostExecute = {
// ... here "it" is a data returned from "doInBackground"
})
}
}
or in Activity/Fragment:
lifecycleScope.executeAsyncTask(onPreExecute = {
// ...
}, doInBackground = {
// ...
"Result" // send data to "onPostExecute"
}, onPostExecute = {
// ... here "it" is a data returned from "doInBackground"
})
To use viewModelScope or lifecycleScope add next line(s) to dependencies of the app's build.gradle file:
implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$LIFECYCLE_VERSION" // for viewModelScope
implementation "androidx.lifecycle:lifecycle-runtime-ktx:$LIFECYCLE_VERSION" // for lifecycleScope

package com.irontec.kotlintest
import android.os.AsyncTask
import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.view.Menu
import android.view.MenuItem
import android.widget.TextView
import kotlinx.android.synthetic.main.activity_main.*
import org.json.JSONObject
import java.io.BufferedInputStream
import java.io.BufferedReader
import java.io.InputStreamReader
import java.net.HttpURLConnection
import java.net.URL
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
GetWeatherTask(this.text).execute()
}
class GetWeatherTask(textView: TextView) : AsyncTask<Unit, Unit, String>() {
val innerTextView: TextView? = textView
override fun doInBackground(vararg params: Unit?): String? {
val url = URL("https://raw.githubusercontent.com/irontec/android-kotlin-samples/master/common-data/bilbao.json")
val httpClient = url.openConnection() as HttpURLConnection
if (httpClient.responseCode == HttpURLConnection.HTTP_OK) {
try {
val stream = BufferedInputStream(httpClient.inputStream)
val data: String = readStream(inputStream = stream)
return data
} catch (e: Exception) {
e.printStackTrace()
} finally {
httpClient.disconnect()
}
} else {
println("ERROR ${httpClient.responseCode}")
}
return null
}
fun readStream(inputStream: BufferedInputStream): String {
val bufferedReader = BufferedReader(InputStreamReader(inputStream))
val stringBuilder = StringBuilder()
bufferedReader.forEachLine { stringBuilder.append(it) }
return stringBuilder.toString()
}
override fun onPostExecute(result: String?) {
super.onPostExecute(result)
innerTextView?.text = JSONObject(result).toString()
/**
* ... Work with the weather data
*/
}
}
override fun onCreateOptionsMenu(menu: Menu): Boolean {
menuInflater.inflate(R.menu.menu_main, menu)
return true
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
val id = item.itemId
if (id == R.id.action_settings) {
return true
}
return super.onOptionsItemSelected(item)
}
}
link - Github Irontec

This is how I do in my projects to avoid memory leaks:
I created an abstract base Async Task class for Async loading
import android.os.AsyncTask
abstract class BaseAsyncTask(private val listener: ProgressListener) : AsyncTask<Void, Void, String?>() {
interface ProgressListener {
// callback for start
fun onStarted()
// callback on success
fun onCompleted()
// callback on error
fun onError(errorMessage: String?)
}
override fun onPreExecute() {
listener.onStarted()
}
override fun onPostExecute(errorMessage: String?) {
super.onPostExecute(errorMessage)
if (null != errorMessage) {
listener.onError(errorMessage)
} else {
listener.onCompleted()
}
}
}
USAGE:
Now every time I have to perform some task in background, I create a new LoaderClass and extend it with my BaseAsyncTask class like this:
class LoadMediaTask(listener: ProgressListener) : BaseAsyncTask(listener) {
override fun doInBackground(vararg params: Void?): String? {
return VideoMediaProvider().allVideos
}
}
Now you can use your new AsyncLoader class any where in your app.
Below is an example to Show/Hide progress bar & handle Error/ Success scenario:
LoadMediaTask(object : BaseAsyncTask.ProgressListener {
override fun onStarted() {
//Show Progrss Bar
loadingBar.visibility = View.VISIBLE
}
override fun onCompleted() {
// hide progress bar
loadingBar.visibility = View.GONE
// update UI on SUCCESS
setUpUI()
}
override fun onError(errorMessage: String?) {
// hide progress bar
loadingBar.visibility = View.GONE
// Update UI on ERROR
Toast.makeText(context, "No Videos Found", Toast.LENGTH_SHORT).show()
}
}).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR)

I always use this form:
open class LoadingProducts : AsyncTask<Void, Void, String>() {
private var name = ""
override fun doInBackground(vararg p0: Void?): String {
for (i in 1..100000000) {
if (i == 100000000) {
name = "Hello World"
}
}
return name
}
}
You invoke it in the following way:
loadingProducts = object : LoadingProducts() {
override fun onPostExecute(result: String?) {
super.onPostExecute(result)
Log.e("Result", result)
}
}
loadingProducts.execute()
I use the open so that I can call the onPostExecute method for the result.

I spent a full day trying to figure how to get back the result produced by an Async Task : co-routines was my solution !!!
First, create your AsyncTask Object ... Do not forget to use corrects parameter type instead all Any
#SuppressLint("StaticFieldLeak")
class AsyncTaskExample(private var activity: MainActivity?) : AsyncTask<Any, Int, Any?>() {
override fun onPreExecute() {
super.onPreExecute()
// do pre stuff such show progress bar
}
override fun doInBackground(vararg req: Any?): Any? {
// here comes your code that will produce the desired result
return result
}
// it will update your progressbar
override fun onProgressUpdate(vararg values: Int?) {
super.onProgressUpdate(*values)
}
override fun onPostExecute(result: Any?) {
super.onPostExecute(result)
// do what needed on pos execute, like to hide progress bar
return
}
}
and Then, call it ( in this case, from main activity )
var task = AsyncTaskExample(this)
var req = { "some data object or whatever" }
GlobalScope.launch( context = Dispatchers.Main){
task?.execute(req)
}
GlobalScope.launch( context = Dispatchers.Main){
println( "Thats the result produced by doInBackgorund: " + task?.get().toString() )
}

if in the case you want to do it without using Anko and the correct way is to use the following way
open class PromotionAsyncTask : AsyncTask<JsonArray, Void, MutableList<String>>() {
private lateinit var out: FileOutputStream
private lateinit var bitmap: Bitmap
private lateinit var directory: File
private var listPromotion: MutableList<String> = mutableListOf()
override fun doInBackground(vararg params: JsonArray?): MutableList<String> {
directory = Environment.getExternalStoragePublicDirectory("Tambo")
if (!directory.exists()) {
directory.mkdirs()
}
for (x in listFilesPromotion(params[0]!!)) {
bitmap = BitmapFactory.decodeStream(URL(x.url).content as InputStream)
out = FileOutputStream(File(directory, "${x.name}"))
bitmap.compress(Bitmap.CompressFormat.PNG, 100, out)
out.flush()
out.close()
listPromotion.add(File(directory, "${x.name}").toString())
}
return listPromotion
}
private fun listFilesPromotion(jsonArray: JsonArray): MutableList<Promotion> {
var listString = mutableListOf<Promotion>()
for (x in jsonArray) {
listString.add(Promotion(x.asJsonObject.get("photo")
.asString.replace("files/promos/", "")
, "https://tambomas.pe/${x.asJsonObject.get("photo").asString}"))
}
return listString}
}
and the way to execute it is as follows
promotionAsyncTask = object : PromotionAsyncTask() {
override fun onPostExecute(result: MutableList<String>?) {
super.onPostExecute(result)
listFile = result!!
contentLayout.visibility = View.VISIBLE
progressLottie.visibility = View.GONE
}
}
promotionAsyncTask.execute(response!!.body()!!.asJsonObject.get("promos").asJsonArray)

I use LaunchedEffect in a composable
LaunchedEffect ("http_get") {
withContext (Dispatchers.IO) {
http_get() }}
and rememberCoroutineScope in a callback
val scope = rememberCoroutineScope()
Button (
onClick = {
scope.launch {
withContext (Dispatchers.IO) {
http_get() }}})
It seems to work, but I don't know why.

private fun updateUI(account: GoogleSignInAccount?) {
if (account != null) {
try {
AsyncTaskExample().execute()
} catch (e: Exception) {
}
}
}
inner class AsyncTaskExample : AsyncTask<String, String, String>() {
override fun onPreExecute() {
super.onPreExecute()
}
override fun doInBackground(vararg p0: String?): String {
var Result: String = "";
try {
googleToken = GoogleAuthUtil.getToken(activity, accountVal, "oauth2:https://www.googleapis.com/auth/userinfo.profile")
signOut()
} catch (e: Exception) {
signOut()
}
signOut()
return Result
}
override fun onPostExecute(result: String?) {
super.onPostExecute(result)
socialPrsenter.setDataToHitApiGoogleLogin(googleToken ?: "")
}
}