Hi everybody, published two super short articles about some Kotlin features on medium and would like to know your opinions. Is that something someone wants to read? https://medium.com/swlh/kotlin-experiments-execution-after-return-ea919f239c4?source=friends_link&sk=f95e650bae29a901bab2f0ab33dfd519 https://medium.com/swlh/kotlin-for-lunch-atomic-t-261351048fad?source=friends_link&sk=28ebe47952f209e552482dfdbad27f49

is there another way to loop an ArrayList in reverse (from last to first) without creating additional lists (such as

.reversed()

) other than

for(i in g.windows.lastIndex downTo 0) {
    val window = g.windows[i]

? Ps: I do need

continue

and

break

inside

This is a library that allows you to spell out the htpp status codes extensively. https://github.com/Romavic/HttpStatusCode

question on Kotlin generics if anyone thinks they might be able to help! https://stackoverflow.com/questions/63992988/instantiating-classes-from-non-reified-type-parameters

Hey guys, is there anyway i can make IntelliJ auto collapse kotlin doc comments like i can with java?

When calling a "suspend" method from Java we can use CompletableFuture, is there a similar Java counterpart when calling a method that returns a Flow<>?

why does

foo::class

return

KClass<out String>

instead of

KClass<String>

, and...what are my options if I actually want the latter?

Hi folks! I bumped into the following issue while trying to port a Java library to Kotlin while keeping JVM API compatibility (i.e. this is why changing the name of the property or the function is not an adequate workaround for me). Here is a prototypical example of the issue:

import kotlin.jvm.JvmField

open class X(
    @JvmField
    open val x : Int = 0,
) {
    fun getX() : Int = x
}

open class XY(
    @JvmField
    val y : Int = 0
) : X()

Trying to compile this little piece of code for the JVM will produce the following error:

Inherited platform declarations clash: The following declarations have the same JVM signature (getX()I):
    fun <get-x>(): Int defined in XY
    fun getX(): Int defined in XY

It seems that the @JvmField defined in X is not inherited by the XY class. From my perspective, this construct is valid and very useful if one want to keep compatibility with an API that offers both field and method-based access... even though this is usually bad yet common practice. Thanks for listening! Luc

Is there a seperate chat for kotlin native?

message has been deleted

Why isn't it possible to pass an object of the type 

ZusammenfassungABC

 , even if it inherits from 

ZusammenfassungAC

 (line 22)?

lateinit

has

isInitialized

to check if the field has been initialized, is there something similar for

Delegates.notNull

?

Is there a mechanism in Kotlin that could trigger the init on an object / class without having to call a blank function?

class TestClass {

	init {
		println("????????????")
	}

	companion object {
		init {
			println("!!!!!!!!!!!!!")
		}

		fun touch() {
			// empty function to trigger init
		}
	}
}

object TestObject {
	init {
		println(">>>>>>>>>>>>>>>>>")
	}

	fun touch() {
		// empty function to trigger init
	}
}

In my main, i literally have to call touch before the TestObject and TestClass' init is called

@JvmStatic
	fun main(args: Array<String>) {
		TestClass.touch()
		TestObject.touch()
	}

i'm tryin to implement some form of inversion of control where classes register themselve to a central place My use-case is building the equivalent of a Controller, but instead of wiring in URLs in a central place, each Controller wires itself in to the central point

Is there in the standard library (or an external one) a fucntion similar to

random.choices

in python ?

Easily overused though

Is there any working Kotlin IDE? I'm losing my mind in IDEA. The Kotlin plugin breaks all day long. Completely unusable, and it feels like it has gotten worse.

Just tried latest 2020.3 EAP and no improvement there either. Constantly red blink in the right corner signalling exception in the Kotlin plugin. Organize import duplicating the last import >50% of the times, and if I'm unlucky, it also smashes up all imports on one single line.

I like the language, but the tooling really tries its best to fend off users 😞

Is there a way to stop

internal

members showing up in auto-completion from Java projects?

I thought they used to be marked as synthetic in the bytecode to prevent this, however, it seems to not (any longer ?) be the case. This is a big pain for us when building APIs in Kotlin

Okay so I have a class:

class ElementRemoveEvent<E>(
    val element: E,
    override val collection: ObservableCollection<E>
) : Event<E>

And it is misbehaving as you can see in the screen shots, what is causing this and how do I get rid of it? Is it outcome of excessive type inference?

Since Kotlin has a strong type-inference, and seems like compiler already know the type which has to be received as parameter to lambda (in the function call), is it possible to reduce the redundant generic E of EventE, and the second generic parameter E itself?

hi; I have the following issue: library A; 1.0.4

data class Test(
  val a: String,
  val b: String? = null
)

library A; 1.0.5

data class Test(
  val a: String,
  val b: String? = null,
  val c: String? = null
)

library B; 1.0.1 -> library A; [1.0, 2.0) // when built -> 1.0.4 library C; -> library B; [1.0, 2.0) -> library A; [1.0, 2.0) now, when building library C again; -> library B; [1.0, 2.0) -> 1.0.1 -> library A; [1.0, 2.0) -> 1.0.5 here; given library A; 1.0.5 gets picked; the library C, when running, gives me

java.lang.NoSuchMethodError: Test.<init>

when it should've ideally not (I think?) can someone help me figure out why this is happening, and how I can mitigate this?

I'm confused about something. In many places the compiler just returns the last thing of a scope, like in lambdas, but sometimes I'm asked to return explicitly by the compiler. What's the rule for returning the last thing in the scope vs requiring an explicit return?

Hi all. I was wondering if there’s a nice way to do something like:

val myObject: MyClass? = map.ifKeyPresent("xyz) { return MyClass(it }.orElse { null }

So, basically, if a map contains the key, convert the value of that key to a different type, and if it’s not there, return something else, for example

null

. Does something like this exist?

Would you like a channel named

naming

for the community to give and receive code naming help? I'm thinking about code related names like symbols (functions, properties, classes, constants…), packages, modules, libraries, etc.

Hello, I am new and want to know which course I should start learning kotlin ? thank you

Why is there no half implicit generics? Like if there's something like

fun <T, E : SomeType<T>> function() {}

Then both T and E needed to be specifed And for example this:

fun <T, E : SomeType<T>> function(v: T) {}

if we pass

function(5)

(T) as one of the parameter then E is automatically taken as SomeType<T>, but why cannot we have half implicit parameter like

function<Int>()

that could implicitly say about the second parameter? Or does it exist, I'm just not noticing it?

Hey guys! I have this annotation

@Retention(AnnotationRetention.RUNTIME)
@Target(AnnotationTarget.FUNCTION)
annotation class Navigate

Being used like

@Feature(Features.Login::class)
object Login: FeatureModel() {
    override var featureItem = Config::loginFeature
    override var action = ".login.open"
    override var fallbackDisplayName = "Login"
    override var requiresLogin = false
    override var version = "1"

    @Navigate
    fun newInstance(): Intent {
        return Intent("TEST")
    }
}

But

Login::class.declaredFunctions.map { it.annotations }

Returns null in the evaluator. Any thoughts?