hi guys, I'm trying to use https://play.kotlinlang.org with com

-Xallow-result-return-type

but seems not work with the play.kotlin. Has anyone tried it before?

But, I do not know whether that should work or not.

according to this answer (https://stackoverflow.com/questions/39679180/kotlin-call-java-method-with-classt-argument) by @apatrida:

The error message could be clearer to say "only classes without generic parameters are allowed on the left side of ::"

ArrayList<*>::class

changes nothing though

this doesnt explain why

Array<VkCommandBuffer>::class

works flawless

Hello. How do you quickly create unit-test for a given class using Kotlin? The problem is that IDE generates file with

java

extension in kotlin source root. Same for Groovy

is there any way to bypass using a built-in infix function for a specific statement (ie: I'm using a library that has a "to" function and it's always using Kotlin's "to" to create a Pair)?

Is there a lint check to prevent not invoking a lambda such as doing

onClick

instead of

onClick()

when

val onClick: () -> Unit

?

Kotlin styleguide recommends to cut that to

src/main/main.kt

. I'm talking about this. Cited this part in linked post above

Running into a kotlin/Java snafu. Received a library written in Kotlin, and the app thats going to use the library is all in Java and there is no plan to introduce Kotlin to that app....yet. The Kotlin library has a public api similar to

fun doBar(callBack: (String, Array<Int>) -> Unit)

. That gets exposed to Java as

doBar(Function2<? super String, ? super Integer[], Unit> callback)

. When ever we try to create a anonymous class of Function2 we get

doBar(Function2<? super String, ? super Integer[], Unit> callback) cannot be applied to (anonymous Function2< String, Integer[], Unit>)

. Is there another way to call a kotlin function interface from Java?

How do you create a copy of a List, that changes references but keeps the objects? I have tried

toList

method but it does not seem to work. Context: I am trying to implement a simple recycler view and update it using DiffUtil, but the oldList and newList are the same for some reason

Hello, I've run into a situation and I've been trying to figure it out. I have an extension function declared at the top level in my module, and I have an extension function declared within a class' scope. When I call a method that changes the receiver to this scope, I can't figure out how to access the top-level function. An example:

fun MyObject.get(str: String): String {
        return get(str) {}
    }

class Scope {
        operator fun Any.get(str: String): Int = 1
}

// within method body
val myObject = MyObject()
val scope = Scope()

with(scope) {
  myObject.get("abc") // calls Scope's get()
}

How do I tell the compiler to call MyObject.get()? Suppose that both extension functions are define din libraries, so I can't easily change those names.

is it just me or is

assert

dead? From what I see on Google it isn't even enabled by default in junit unit tests afaik

Could you give an example?

Hi, I am playing with GraalVM APIs and realize the polyglot API cannot change Kotlin class members' values, while it can in Java. Why does this happen ??

java
import org.graalvm.polyglot.Context;
class Scratch {
  public class Response {
    public int x = 2;
  }
  void run () {
    Context context = Context.create();
    Response r = new Response();
    context.getBindings("js").putMember("r", r);
    context.eval("js", "r.x = 42");
    System.out.println(r.x); // print 42

  }
  public static void main(String[] args) {
    new Scratch().run();
  }
}

How to pass arguments to the kotlin command line? I cannot find example (https://kotlinlang.org/docs/tutorials/command-line.html) Same as in Java: java exampleClass 5000 java exampleClass 0 < input.txt

are delegates a bad practice if they break encapsulation by requiring a public API?

Due to its extensions and overall syntax philosophy, kotlin is the only language where i feel i can consistently write functions in the form of

subject.verb(object)

. I personally hate syntax like python's

len(list)

, because I feel like as a property of the list, it should be called as

list.len

, and that

len(list)

implies some kind of transformation of

list

Hello eveyone, I had a question with how to approach unit testing. Right now I am working on a small multiplatform library with 98% of the code in the common source set with the rest being some platform-specific implementations in jvm and native. I have all the unit tests in the common-test source-set but now I need some add some junit unit tests for code that will trigger coroutines. The recommendations online to handle coroutines in UT is to wrap them in runBlocking, but this is only available in native/JVM. Is there any other way to have my Unit Tests remain in the common package while also calling into coroutines?

Does anyone know why

MyClass::class.simpleName

is of

String?

type? Why is it not

String

?

https://twitter.com/kotlin/status/1102587197033799681 We created a little video to celebrate three years of Kotlin which we wanted to share with you, our amazing lovely community. Enjoy! https://t.co/RZIvoBDqrT Twitter

Hi, how to obtain all functions that have a functional parameter using Kotlin Reflect? I tried something like

Class.forName("myClass").declaredMethods.map { it.kotlinFunction!! }.filter { fn -> fn.parameters.any { it is KFunction<*> } }

but it didn't work

why I dont have any

associatedWithTo

on

Enum.values()

(

Array<T>

)? https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/associate-with-to.html

Hey, i'm new here. the above snippet is for my question. I create a client from an api, and it has a getIdleTimer function. I want to check the idleTime every x seconds, and then do something when a certain time has passed. so I implemented the coroutinescope on the client, and made the snippet so it checks every x time. my question is, do I have to save the coroutine and fixedrate time in a variable that I'll probably never touch again?

What could be a good way for provide a compile time - type safety on

Any

? Let’s say that I got this class and I want the better way for ensure that

image

is

Drawable, Int, Bitmap, File, String or Uri

and placeholder is

Drawable, Int, Bitmap or File

without crashing at runtime

Hey guys, I run into trouble while publishing a project. I am not absolutely sure, but I guess I found a bug in the kotlin gradle plugin. For some strange reasons there is a "maven" publication from nowhere. I think the kotlin plugin might create that one. For now I just found a reference in MPP, but I think there is also something for "normal" projects. Is there someone familiar with the gradle plugin? I already opened a bug on a differnt project for more details check this link: https://github.com/novoda/bintray-release/issues/266

Hey guys, I have the following scenario: I want to send a lambda/function to a different thread defined in a different module too. Both threads (sender and receiver) have a common dependency where the lambdas/functions are defined. However when I serialize the lambda to a byte array in line number 17, ::toLong is not referencing the definition of such function in Lambdas.kt but something like Main$1$… what makes module C not being able to deserialize it because is not able to find the class Main$1$… since it does not have the dependency. Why is it ::toLong not referencing the definition contained in Lambdas.kt of module A?

This message was deleted.

I need some compilation safety for the following scenario: I want to create a specific object for each type of a sealed class. Is that somehow possible?

My current idea is to showcase how kotlinlang improves implementation of and, in some cases, obsoletes some of Effective Java’s recommendations

Where's the best place to ask a question about Kotlin-Java interop, specifically for java.util Collections vs kotlin.collections?