Hi guys! 🙂 I’m looking to rewrite some of our old Rx code with flow but I just can’t get my head around this one... What I’m looking to do is : collect a flow with a timeout, everytime I collect a value, check if it satisfies a certain condition else keep collecting And I need a way to know if, at the end of the timeout, nothing was collected. I feel like I’m somewhat close with this but it just doesn’t seem to be working like I want 😕

val result = withTimeoutOrNull(10000L) {
    flowProvider.getFlow().collect {
        if (it.condition) // ALL GOOD, can exit collect and keep going
        else // Not good enough, collect some more and see if I can get a match
    }
}
if (result) == null // Assume nothing was collected?

Is it even feasible this way?

maybe I can open a feature request on the kotlin plugin to flag any set operators on

Collection<A> op Collection<B> -> Collection<Serializable>

as suspicious?

Hi all! 👋 We are working to improve the experience of getting started with :kotlin: Kotlin for all newcomers, and we would value your feedback about our latest design. We invite: • experienced backend developers who plan to start using Kotlin or who have recently started using it • mobile developers who plan to start using Kotlin Multiplatform Mobile or who have recently started using it  To participate in a short study. The whole thing won’t take more than an hour. 👉 If you are interested, please fill out this form. With love, Kotlin Team.

What are the possible consequences if I ignore ‘Package directive doesn’t match file location’ issue?

Is there a way in Kotlin to match a regex until some character without creating a substring? Like

find(input, 50)

to search after character 50 but so that only until character 50 is tried to match. And what is the difference between

slice

,

substring

and

subSequence

?

Are there any docs/talks about how you sold Kotlin to your team? I am planning to do so at Salesforce and I need a reference for my pitch. Thanks

I have a class a bit like this:

class Vector(val x: Double, val y: Double, val z: Double = .0) {
    operator fun div(n: Double) =
        Vector(x / n, y / n, z / n)

    fun magnitude() = sqrt(x*x + y*y + z*z)

    fun normalized() = when (val m = magnitude()) {
        0.0 -> Vector(x, y, z)
        else -> this / m
    }

    // more stuff
}

and I want to have another class with most of the same functionality, but more like as a wrapper, where

x

and

y

are

Int

but everything else is computed with `Double`s, and with 2 additional

Int

properties

targetX

and

targetY

. Is there anything in Kotlin that can help me achieve this without writing every method that wraps another method? (or any good idea?) I tried using`by` with an interface to delegate but the types (

Int

and

Double

) wouldn't match so it wouldn't work.

Hi guys, live tomorrow. And I want shared with all you: thanks

hey folks, I’m leaning Spring boot. To begin with I’d like to build a MPA (multi page application), which is just a normal non spa website. What is the be templating engine for spring boot ? One I could insert javascript/vue.js components in it ?

How do you name your Dao method in kotlin?

foo(), getFoo(), loadFoo(), findFoo()

?

I have a class:

val c = Array<Int>::class

I want to get the parameterized type of c (i.e.

Int

). Is this possible on the JVM?

is there an easiest/shorter way to drop the

g

in a string such as

v0.1.9-1-g3a259e0

(which is always "$version-g$commitId") other than using something relying on

lastIndexOf(-g)

and then combining the two substrings?

What are for

.kotlin_module

files are used? I can not open it in IDE unfrotunately

Why does the explicit api mode require me to annotate functions of interfaces with a visiblity? Is anything but public even valid on interfaces?

Why isn’t it allowed to pass the constant

0

to a

Double

? Why

0.0

?

At first, I used to take Result. But, it removes me the possibility to have an exhaustive result sealed class that I can treat in the caller with when keyword. Which is very nice at compile time.

hello, does anyone knows how i can make the user change his picture by pressing on an imageButton without using firebase or so? And is there a way to save the image using shared preferences? (I’ve tried googling it 😅)

Hello. I'm using kotlin 1.4.30 in a multi-module project. When I make a change at the code, it seems that Intellij is not compiling the new code. I need to always run gradle clean first, so my changes take effect. Has anyone been thru this before?

anybody else experiencing index corruption / index issues with kotlin in intellij idea currently? not a single day without purging and recreating the cache 😞

I find it very hard to get to the javadoc (or should I say kotlindoc) for kotlin classes. If I go to the kotlinlang website and enter "flow" as a search request, I find articles about flow but not the javadoc.. Is it available somewhere? Is there a magic query that can show me results for only javadoc (not the whole documentation)?

Is there a way to reduce compile / test cycles like REPL or Hot Reload with Kotlin? only thing I saw is jrebel

Has anyone figured out how to mimic Rust's dbg! macro with Kotlin? From Rust docs

fn factorial(n: u32) -> u32 {
  if dbg!(n <= 1) {
    dbg!(1)
  } else {
    dbg!(n * factorial(n - 1))
  }
}

I hope to be able to write something like this in Kotlin

fun factorial(n: Int): Int {
  if (dbg(n <= 1)) {
    return dbg(1)
  } else {
    return dbg(n * factorial (n - 1))
  }
}

Possible incomplete implementation

fun <T> dbg(expr: T): T {
  println(expr)
  return expr
}

Is there any way to capture the expression syntax itself rather than the value?

Is there something like

Function1

but as consumer, so without return value?

Hi Guys! I found

elementAt()

 function on collections, I started to wonder which one is better for getting values,

elementAt()

or

get()

.. Found only this line

element at is useful for collections that do not provide indexed access, or are not statically known to provide one.

, so does that mean

elementAt()

is useful for non-index-based collection? like LinkedList? maps? graphs? Even examples show https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/element-at.html arrays and List sample not other once.. is it because there is only list, set, and map in collections of Kotlin?

Random thought - one of things I like about Kotlin is the ability to chuck a bunch of classes and functions into a file during the rapid prototyping phase. Then IntelliJ makes it easy to refactor it into separate files later. Java, so many files being created and renamed and deleted....

message has been deleted

I'm struggling trying to get a modular build to work with a library that doesn't seem to expose a module:

Exception in thread "JavaFX Application Thread" java.lang.IllegalAccessError: class net.nprod.bcm.separation.PeakSimulatorKt (in module bcm) cannot access class smile.math.special.Erf (in unnamed module @0x4993dace) because module bcm does not read unnamed module @0x4993dace

Hello, does anyone know how to save the checkbox state and value is fetching data from an api? I stored the data in a List, my recycle view is working, and everything works fine, buthow can I save the checkbox state and the text value so I can print it in a grid view in another page? I am using kotlin

Is there a nice way to define a list of extension functions? Background: in one of our user group discussions we discussed various ways to code "replace or add" for lists. We then wanted to test all of the proposed solutions using a `listOfProposals.forEach { f -> ... }`but could not find a way to define such a list. The best I have right now is to use a list of non-generic anonymous functions, where each item calls one of he proposed solutions. But that does not look "nice":

fun <T> List<T>.replaceOrAdd1(item: T, predicate: (T) -> Boolean): List<T> { ... }
fun <T> List<T>.replaceOrAdd2(item: T, predicate: (T) -> Boolean): List<T> { ... }
data class Person(val name: String, val age: Int, val email: String, val address: String = "")
val listOfProposals = listOf(
    fun(list: List<Person>, person: Person, predicate: (Person) -> Boolean) = list.replaceOrAdd1(person, predicate),
    fun(list: List<Person>, person: Person, predicate: (Person) -> Boolean) = list.replaceOrAdd2(person, predicate),
)
// <https://pl.kotl.in/GvbQWnFEq> is the link to the working example