Coroutines delegate exceptions Currently, I have some scenario like this where I have java interface callback which looks something like this. Java Callback interface Callback { void onComplete(T result) void onException(HttpResponse response, Exception ex) } Suspending function for the above look like this suspend fun awaitCallback(crossinline block: (Callback) -> Unit) : T =...

SimpleEmail forces SMTP to port 465 I've been trying to send an email programmatically from the server using SimpleEmail. I use Kotlin. So far it always leads to an error that seems to only use port 465 despite setting it to a different port. I've been trying to find out why it does this but I have not seen any point this out. SimpleEmail().apply { hostName = "smtp.gmail.com" setSmtpPort(587) setAuthenticator(DefaultAuthenticator("**email**", "**password**")) setSSLOnConnect(true)...

How to set val property with Kotlin reflection? I would like to return a copy of a class with a different value assigned to a val property. data class Person(val name: String, val age: Int) fun main() { val person = Person("Morné", 25) val property = person::class.declaredMemberProperties.first { it.name == "age" } person.copyWithValue(property.name, 22) } if age was a var then I could do it like follows: fun main() { val person = Person("Morné", 25) val property = person::class.declaredMemberProperties.first {...

About the problem of instantiating classes in Kotlin reflections This is java code: public class TUtil { public static T getT(Object o, int i) { try { return ((Class) ((ParameterizedType) (o.getClass() .getGenericSuperclass())).getActualTypeArguments()[i]) .newInstance(); } catch (InstantiationException e) { } catch (IllegalAccessException e) { } catch (ClassCastException e) { } return null; } } //use code： public abstract class...

Destruct withIndex() iterator Messing around with destructing declarations and the following perplexes me: private data class TestData(var i: String, var j: Int) : Any() {} private var mlist = mutableListOf() fun main(args: Array) { mlist.add(TestData("Hi", 5)) mlist.add(TestData("There", 53)) mlist.add(TestData("Test", 2345)) for ((i, v) in mlist.withIndex()) { println(i.toString() + " ok "...

How to call Method from in Kotlin? I have a two files one.kt and two.kt, i have innerclass in one.kt file. i want to call the that innner class when some action performed like button click in Two.kt file. I tried some of ways but the innerclass or method does not call. please guide me what i had mistakes. The One.kt file call from manifest file. like this,

Add Image Into RecyclerView Android Using Kotlin how I can add image from drawable dynamically into recycler view using kotlin? Here is my MainActivity.kt class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) val binding: ActivityMainBinding = DataBindingUtil.setContentView(this, R.layout.activity_main) binding.get = Get() //parse array klaxon var products = Klaxon().parseArray(addProducts()) if (!products!!.isEmpty()) {...

Why does google maps not work in release version but it does on debug this question seems to complex for me, because I don't really know which files to attach for this. I always played my app on the emulator and via USB debugging on my smartphone. never had I any problems to show googlemaps. Now I wanted to share the .apk file, so I made a signed apk file and installed this on my device. Every part of my Code workes fine, but instead of showing googlemaps it just shows a lightgrey color. Where could the problem be? My Manifest file:...

Kotlin with Dagger 2 We are developing new Android app, only using Kotlin language. We want to use Dependency Injection framework. Dagger 2 is Java based framework. As of my knowledge, There is no Kotlin based DI framework from Google. Is it advisable to use Dagger 2 with Kotlin? When can we expect Kotlin based DI framework from Google? If so, is it backward compatible with Dagger 2 to adopt quickly?

LiveData, MVVM and Repository Pattern Is this a good approach or I've just found a nasty workaround? I'm using MediatorLiveData class because seems useful to update the source of a LiveData object. I mean, the majority of tutorials that I've found on internet just use Livedata or MutableLivedata without a dynamic source, in example: fun search(/*no input params*/): Call But in my case, I have the following web service that performs a search by name: interface APIServidor { @GET("search") fun search(@Query("name")...

passing null as aparameter to listOf can you please tell me what does the second parameter passed to the method listOf means? why do we need to pass null? why is the purpose of it? code: val listWithNulls: List = listOf("Kotlin", null)

WorkManager problem with PeriodicWorkRequest and LocationUpdates WorkManager version : 1.0.0-alpha08 i tested it for many days it worked fine. But now its not working properly. Actually I was fetching device location at interval of 15 minutes and sending it to the server. So I used PeriodicWorkRequest for that. And later I made another sample just to check but again its not working sometime it runs at given time interval and most of the time it is not doing its task at that interval. Please suggest is it any issue in WorkManager library or any problem from...

Android Studio - Where is Kotlin installed? I have macosx and I would like to use kotlin from terminal. Then I would like to find where is kotlin installed, since I'm using it from Android Studio. I know i can install Kotlin using homebrew but I want avoid having two copies of Kotlin.

How to make Alert dialog items? I want to create alert dialog items. Here is my code. val colors = arrayOf("Red","Green","Blue") val builder = AlertDialog.Builder(this) builder.setTitle("Pick a color") builder.setItems(colors) {, -> Toast.makeText(this,"Red Color",Toast.LENGTH_LONG).show() Toast.makeText(this,"Green Color",Toast.LENGTH_LONG).show() Toast.makeText(this,"Blue Color",Toast.LENGTH_LONG).show() } builder.show() } } In result an...

Kotlin "ternary operator" using WHEN How to write Kotlin conditional if (a) b else c using WHEN

MVVM and Dagger 2 - Benefits We are developing new Android application. We are trying to use MVVM and Dagger 2. What are all the benefits of using Dagger 2 if we use MVVM?

How to remove item from ArrayList in Kotlin var arrayone: ArrayList = arrayListOf("a","b","c") val arraytwo:ArrayList = arrayListOf(arrayone.removeAt(0)) for (item in arraytwo) { println(item) } I just want to remove item from the first array and make a new array. But this just prints one item at index 0

how to fetch two fields from a single repository in springboot @Repository interface SchemeMemberRepository:JpaRepository { fun findBySchemeMemberName(schemeMemberName:String) : Optional } In the code, I have fetched by schemeMemberName. Can it be fetched by two fields? As shown below. @Repository interface SchemeMemberRepository:JpaRepository { fun findBySchemeMemberName(schemeMemberNameString,NameString) : Optional }

How Can I Draw Cells Inside MPAndroidChart How can I draw cells inside LineChart I am able to display lines dynamically, but didn't find how to draw inner cells. I have followed these examples https://github.com/PhilJay/MPAndroidChart/issues/3751 MPAndroidChart- How to add cells inside grids like Graph sheet? any...

Kotlin callback not called within async function I am attempting to subscribe to multiple characteristics of a BLE peripheral within Android API 28. Due to the asynchronous nature of the BLE API I need to make the function that subscribes to each characteristic (gatt.writeDescriptor()) block; otherwise the BLE API will attempt to subscribe to multiple characteristics at once, despite the fact that only one descriptor can be written at a time: meaning that only one characteristic is ever subscribed to. The blocking is achieved by...

How to implement Collection/List interface or abstract class in Kotlin I'm having trouble implementing the iterator and get set functions. In the past, I've inherited from ArrayList even though I need a fixed-size collection. I've also used an Array property and operator get and set funcions, but these two just feel like unnecessary workarounds. Also, I've noticed that Kotlin doesn't actually have an Implementation of List, Instead there's a function called List which returns some implementation of the interface. Can someone please explain how does that work?

Bottom Sheet Drawer in Material design class BottomNavigationDrawerFragment: BottomSheetDialogFragment() { override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? { return inflater.inflate(R.layout.fragment_bottomsheet, container, false) } override fun onActivityCreated(savedInstanceState: Bundle?) { super.onActivityCreated(savedInstanceState) navigation_view.setNavigationItemSelectedListener { menuItem -> // Bottom Navigation Drawer menu item clicks...

Android DataBinding change typeface of other view on click I have a filter bar that shows a separate TextView for each letter ("A", "B","C"...). I want to achive that, when I click on the TextView with A it gets bold, and all other TextViews should go back to normal font style. If I then click on C, A (and all other) TextViews should show normal and "C" should show bold font. Is there an efficient way to to this with data binding? I want to avoid to write a LiveData-property for each of the textfields.

How do you properly replace a dependency for testing? So I want to disable logging for JUnit Tests. Simplest way would be to switch the binding from slf4j-simple to slf4j-nop. How do I do that, though? I tried exclude: dependencies { implementation fileTree(dir: 'libs', include: ['*.jar']) implementation"org.jetbrains.kotlinkotlin stdlib jdk8$kotlin_version" implementation "com.android.supportappcompat v7$support_version" implementation 'com.android.support.constraintconstraint layout1.1.2' implementation...

Android Jetpack Navigation component issue with splash fragment as root destination Suppose we have 3 fragments with toolbars with up button functionality SplashFragment -> FragmentA -> FragmentB This is the expected flow of app. On reaching FragmentB when user presses back button he should go to FragmentA and again on pressing back button the app should exit. How can we achieve this behaviour using navigation component? I have tried to do this using the app:popUpTo inside the action tag, somehow I managed to make it work for hardware back button but the behaviour for up...

Saving and restoring Kotlin lambda with savedInstanceState How to save Kotlin lambda in fragment before the screen rotation? It works in Activity but doesn't correct works in the fragment. An exception occurs when executing a lambda expression if it contains calls to methods of the child class of PermissionsFragment, Why? Class which stores lambda in itself: class ActionKeeper(var action: ((isGranted: Boolean) -> Unit)? = null) : Serializable Fragment which saves lambda to ActionKeeper on screen rotation: abstract class PermissionsFragment :...

Data binding to objects of a complex type in an MutableList I have an activity that should display a non-fixed amount of fragments. Each fragment will receive an element of a MutableList of Customer and it needs to have its components bound to a property in this Customer class. I've created the class like this: class Customer constructor( val name: LiveData val email: LiveData ) In my ViewModel I've created the MutableList of Customer: class CustomerViewModel: ViewModel() { val customers: MutableList = mutableListOf() } Then I...

deserialization of dynamic object using Gson Here explained it for Generic types https://stackoverflow.com/a/8829656/4553806 but in my case there dynamic type of object, not only dinyamic type of fields So it can be one of this class Test1(val par1:String, val par2:Custom1) class Test2(val par1:String, val par2:Custom2) class Test3(val par1:String) how to deserialize json in this case?

Animation not working in AnyChart Circluar Gauge chart in Android I am using AnyChart library for Android. I tried circularGauge.animation(true, 3000) but it seems to be not working. Below it the code snippet fun setCircularChart(anyChartView: AnyChartView, progress_bar: ProgressBar, chartIndex: Int, data: ArrayList, chartTitle: String) { APIlib.getInstance().setActiveAnyChartView(anyChartView) val circularGauge = AnyChart.circular() if (data.size == 0) { return } anyChartView.setProgressBar(progress_bar)...

Consume complex api data using retrofit {"data": { "item1": { "name" : "Box" "price" : "50" }, "item2": { "name" : "Bottle" "price" : "250" }, ..... "item20": { "name" : "Pen" "price" : "100" } }} This is my API structure. I cannot create separate POJO classes for 20 items as it is not efficient . What is the best way to fetch the name and price of every item and set them to a recycler view?