Hi, I find that this code generates 4 classes to represent ‘::x’, is it a bug? Thus making ‘::x === ::x’ equals false.

fun main() {
    val a = ::x
    val b = ::x
    val c = ::x
    val d = ::x
}

fun x(){

}

Hi, I really like

buildList

and I was wondering if there is a way to use it without having to write

@ExperimentalStdlibApi

everywhere.

Hi, does any one thought about concept - "*Explicit Catch Exceptions*"? It would be a kind of exception which can be caught by specifying it explicitly try { } catch (e:ExceptionType) { } and impossible to catch in otheF ways. For e.g. this would solve problems with CancellationException propagation, using flow api. Currently there are cases where we need to explicitly catch and rethrow these "internal" exceptions and code is like: try {} catch (e:CancellationException) { throw e } catch(e:Exception) { } Usage would be annotate exception class with @ExplicitOnly annotation like this:

@ExplicitOnly public expect open class CancellationException(message: String?) : IllegalStateException

In case anyone else missed it: https://youtrack.jetbrains.com/issue/KT-34743 🎊 Trailing commas !

Do we anything equilavent to scala fmt for Kotlin. https://scalameta.org/scalafmt/

abstract class BaseEventConsumer<EV : TBase<EV, out TFieldIdEnum>, ID>(val topic: String) we are using kafka, and I don't understand the meaning of EV, EV: TBase<EV, out TFieldEnum> .

is their a possible way to have an object deconstruct into a variable amount?

Hello, World! Isn't there an equivalent of

forEach

on collections but with a lambda with the element as a receiver (instead of

it

)?

Can anyone tell why this works in Fragment A but not in Fragment B. Fragment A:

viewModel.toolbarViewConfig.title.value = "What do you want to do?"

Fragment B:

activityViewModel.toolbarViewConfig.title.value = "Make $$$"

More Code Fragment A:

val viewModel = ViewModelProvider(activity!!)
    .get(MainActivityViewModel::class.java)

viewModel.toolbarViewConfig.title.value = "What do you want to do?"
viewModel.toolbarViewConfig.isMenuVisible.value = true


return inflater.inflate(R.layout.fragment_home, container, false)

More Code Fragment B:

val viewModel = ViewModelProvider(this).get(GoOnlineViewModel::class.java)
val activityViewModel = ViewModelProvider(activity!!).get(MainActivityViewModel::class.java)
val binding = DataBindingUtil.inflate<FragmentSellerGoOnlineBinding>(
    inflater, R.layout.fragment_seller_go_online,
    container, false
).apply {
    this.lifecycleOwner = viewLifecycleOwner
    this.viewModel = viewModel}

activityViewModel.toolbarViewConfig.title.value = "Make $$$"
activityViewModel.toolbarViewConfig.isMenuVisible.value = false

viewModel.navigationCommand.observe(viewLifecycleOwner, Observer {
    when(it) {
        is <http://NavigationCommand.To|NavigationCommand.To> ->
            Navigation.findNavController(requireView()).navigate(it.directions)
    }
})



return binding.root

I'm not able to override the value

viewModel.toolbarViewConfig.title.value

in fragment B

is kotlin future of android development

I am having problem and getting some exceptions maybe some had the same problem I have posted my question to stackoverflow https://stackoverflow.com/questions/61139367/how-to-implement-room-database-with-coroutines-correctly?noredirect=1#comment108162167_61139367

Anyone was able to setup CI with Github on a Kotlin repo?

Is it best practice in kotlin to use imports with

*

or is it prefered to write out all import statements?

Is it possible to leverage data classes while also ensuring they are created in a consistent state (e.g. by using a factory method)? After reading the following, it seems not, but I wanted to make sure: https://www.reddit.com/r/Kotlin/comments/78dl7m/data_class_factory_constructor_issue/

Post your answer and then try in Ide. If your answers match, kindly reason this, you are great😉 . I couldn't understand the working of this one

In Java, it is possible to declare an object of a type

Something<?>

to say that the generic is ignored. Is there any similar syntax in Kotlin? If so, where can I find documentation that explains how to use it?

Hey guys, I tried to read this block of code (from kotlin docs) a few times but I can't understand 3 things. 1. Red part- why is there a semicolon there? 2. Blue part - how is the

parent

which is a

Person

type can just call the

children

variable as like this list is a part of it? 3. I am also not sure how a

Person

instance is passed to the constructor of a class which is

Person

Source: https://kotlinlang.org/docs/reference/classes.html

is there a way to have extension function only applicable to sealed classes, like (pseudo):

inline fun <reified T : Any> T.ext() "where T::class.isSealed" {}

enum class MyType { A, B, C }

data class MyTypeWrapper(val id: String, val type: MyType)

// existing code to order types based on some business rules
fun mapToOrderedTypeList(unordered: List<MyType): List<MyType> { return ... }

How do I order a list of `MyTypeWrapper`s based on order of their `type`s?

If anyone wants to give it a try. I have been scratching my head 4 days now. All kind of help would be appreciated. https://stackoverflow.com/questions/61178954/data-binding-behaving-unexpected-between-fragments-and-activity

Morning 😄 Is there a way to get rid of these? A bit annoying

Did I encounter a bug? consider the following code:

typealias Point = Pair<Int, Int>
val (axis1, axis2, pointConstruct) = when(horizontal){
    true -> Triple(0..height, 0..width, {a1, a2 -> Point(a1, a2)})
    false -> Triple(0..width, 0..height, {a1, a2 -> Point(a2, a1)})
}

Instead of telling me:

Type cannot be infered

on a1,a2 in any of both lambdas, it simply states that Point is unreachable code. Alongside; it states that pointConstruct is a

(Nothing, Nothing) -> Point

function simply declaring:

val pointConstruct = {a1, a2 -> Point(a1, a2)}

will correctly tell me that a1 and a2 cannot be infered. Why does it infer a

(Nothing, Nothing) -> Point

in the deconstructed lamba, but a compile error on the single line one?

Is there any way to turn on

allWarningsAsErrors

but allow deprecation warnings?

allWarningsAsErrors

is nice, but it prevents us from using

@Deprecated

annotation to provide seamless code migrations 😕

is there a reason behind the ‘eager’ evaluation of safecalls in kotlin?

data class B(val i: Int)
data class A(val b: B)

class Test {
    var a: A? = A(B(1))
    fun get(): Int {
        return a?.b.i ?: -1
    }
}

the expression

a?.b.i

must in kotlin be written as

a?.b?.i

but in reality, if

a

isnt null, we know that

b

must contain

i

(in Swift i think the former expression is valid)

Hey! o/ I'm in need of making some archives and for the sake of "universality" I decided to go with ZIP, and so I'm wondering if there's any nicer way than Java's zip module 😅 Thanks in advance!

hello everyone, I'm new to kotlin and I am looking for resources to help me practice..

Is there any way to access base implementation of class delegation?

interface Base { fun foo(): Int }
object A {
    fun createBase(): Base =
        object : Base { override fun foo(): Int = 1 }
}
object B : Base by A.createBase() {
    override fun foo(): Int {
        // CANNOT access 'super', how to access instance created with 'createBase()' ?
        return super.foo() + 1
    }
}

How can I suppress warnings about the opt in marks? I have allWarningsAsErrors enabled but now my build fails because I have opt in free compiler args applied on all modules and now it prints warnings on

w: Opt-in requirement marker kotlinx.coroutines.FlowPreview is unresolved. Please make sure it's present in the module dependencies

for example

I find it interesting that Android Studio tells me there is a 1.3.72 Kotlin release before I read anything about it here… 🙂

The following structure is repeated in my code:

val arrayList : ArrayList<String> = arrayListOf()
for(person in 0..listOfPersonsIndex){
arrayList.add(person[i])
}

I would like to no do that declaration of empty arraylist and the assign it. Is there a cleaner way to immediately assign a value for it in the stdlib?