kotlinlang #getting-started

Join the conversation Join Slack

Channels

100daysofcode

100daysofkotlin

androidgithubprojects

cincinnati-user-group

competitive-programming

event21-community-content

java-to-kotlin-refactoring

jvm-ir-backend-feedback

kotlin-multiplatform-contest

kotlinultimatechallenge

myndocs-oauth2-server

naming

navigation-architecture-component

practical-functional-programming

proguard

prozis-android-backup

refactoring-to-kotlin

russian-kotlinasfirst

skia-wasm-interop-temp

stayhungrystayfoolish

swagger-gradle-codegen

tricity-kotlin-user-group

getting-started

hho

09/26/2017, 2:53 PM

listOf(1, 2, 3, 4, 5, 6).chunked(2, { it[0] to it[1] }).toMap()

seems to work, but you're creating a

List

for every map entry... (EDIT: Cleaned up thanks to karelpeeters)

karelpeeters

09/26/2017, 2:54 PM

(You can use

to

to clean that up a bit, and

it[0]

for that matter)

hho

09/26/2017, 3:20 PM

FWIW: https://github.com/Kotlin/KEEP/issues/11#issuecomment-332233555

kozhuhar.kirill

09/27/2017, 12:15 PM

fun main(arr: Array<String>) { var b: Int? = null listOf("a", "b", "c").forEach { b?.let { println("${b + 1}") } } }

kozhuhar.kirill

09/27/2017, 12:32 PM

https://kotlinlang.slack.com/archives/C0B8MA7FA/p1506509062000191

sureshbabuinfo

10/01/2017, 6:55 PM

Thank you @karelpeeters . Here @value is spring annotation. Spring will substitute it’s value from properties file during runtime

Prateek

10/01/2017, 6:55 PM

@karelpeeters do you agree that by default the var/val in a kotlin class is public?

jtonic

10/02/2017, 7:00 PM

Hi. In my kotlin project (maven based) I was trying to configure the compiler switch -Xjsr305=warn, to instruct kotlin compiler to emit warns instead of errors. But I didn’t manage to make it work. - In idea I put this compiler flag in additional command line parameters. - In maven I put the following:

<plugin>
        
        <artifactId>kotlin-maven-plugin</artifactId>
        <version>${kotlin.version}</version>
				<configuration>
					
					<jvmTarget>${java.version}</jvmTarget>
          <args>
            -Xjsr305=warn
          </args>

Do you have any idea how can I config it? Thank you in advance.

karelpeeters

10/03/2017, 7:48 AM

That's not how maps work, they don't really have an order most of the time.

genovich

10/03/2017, 9:38 AM

Looks like issue

stepan.zalis

10/03/2017, 5:11 PM

Hi, I have a stopwatch in recyclerview.. Evyrything works fine until I start to scrolling and holders are reused.. Problem is that the holder should be empty, but it is “ticking”, because it is reused, any ideas? I hotfixed it to set holder not to be reusable, but it is paining

10/04/2017, 4:18 PM

all, I'm working through the kotlin koans, but the generics section trips me up a bit. I've been away from java for sometime, so humour me. In "fun <T, C:MutableCollection<T>> Collection<T>.partitionTo(first: C, second: C, predicate: (T) -> Boolean): Pair<C, C>", how should one read "<T, C: MutableCollection<T>>"? As I understand it, the code preceding the function name is the type parameter...but in this case, what is it stating the type is? The "," is throwing me for a loop...

vicpinm

10/05/2017, 7:56 AM

Do you mean something like B.plus(A)?

vicpinm

10/05/2017, 7:57 AM

If I do that, B items are not updated with A items with same id, B items are updated only with new A items that are not in B

vicpinm

10/05/2017, 10:39 AM

A + B produces the same result

lupajz

10/05/2017, 3:09 PM

While we are at sequences what are differences between

buidSequence

generateSequence

is it only that the later takes suspendable function ?

Rockstar

10/05/2017, 3:12 PM

How to use Kotlin in Android Studio?

👍 1

:google: 1

jabba

10/08/2017, 10:50 AM

Karel: I think you mistyped. "The receiver is evaluated first, so also will return

. In the passed lambda, `a`'s value is assigned to `b`" would be the correct way, no?

fstn

10/09/2017, 9:49 AM

Ok,I will read more carefully the documentation then 😉

:google: 3

nil2l

10/10/2017, 9:34 AM

DefaultClass<T>::class

karelpeeters

10/10/2017, 9:35 AM

Shouldn't it be

KClass<DefaultClass>

? What does the generic parameter on DefaultClass do here?

nil2l

10/10/2017, 10:59 AM

There is no

Foo<T>::class

at all. You should provide both: class and its parameter.

Andreas Sinz

10/11/2017, 1:47 PM

@miha-x64 how does your

RootPresenterTag.get()

look like?

Rajesh

10/11/2017, 2:02 PM

Is it possible to decompile .class files to Kotlin in intellij ? The .class files that are originally kotlin are now decompiled to java. It is much easier to see kotlin code decompiled to kotlin.

ayubi

10/11/2017, 2:11 PM

Hello, I am confused between kotson, klaxon, Gson, Jackson with Kotlin module for parsing JSON in Kotlin. Is there any recommendation/standard, usability issues. Asking for a new project. Where my JSON string might have missing data and I want to use immutable data classes. Anything I should consider before going with any one of those? Any comparisons? Performance issues? Any help would be appreciated.

karelpeeters

10/11/2017, 3:52 PM

The getter needs to be ~~more~~ at least as visible as the setter if that's what you're talking about.

👍 1

Karolo

10/11/2017, 11:31 PM

Hi, I will jump into discussion with my question, so if iterrupting I am sorry 🙂 I have in object Foo var with custom setter:

var foo: ((Long) -> Unit)? = null
        set(value) {
            update()
        }

And the problem is when setting it from another part of code like that:

Foo.foo = {it-> doSomeJobWithIt(it) }

it still after such verified call stays null. I am sure that setter is called but somehow my foo inside Foo is still null. Is there something I am missing with variables in object's ? Thanks in advance!

Prateek

10/12/2017, 5:19 AM

all fields are correct

todd.ginsberg

10/12/2017, 3:20 PM

What the heck did I just run then? I swear that said

when I ran it... now it says 53. 🤔

fstn

10/13/2017, 5:04 AM

Is there a better way than using java Completable to do that kind of things :

val result= CompletableFuture<String>()
        eventBus.consumer<context.Context>(eventName, this).completionHandler { 
            if(it.succeeded()){
                <http://logger.info|logger.info>("Register ${this::class.simpleName} for event $eventName")
                result.complete(this::class.simpleName)
            }else{
                logger.error("Unable to register ${this::class.simpleName} for event $eventName")
                result.completeExceptionally(UnableToRegisterServiceTaskException())
            }            
        }
        return result

Title

fstn

10/13/2017, 5:04 AM

Is there a better way than using java Completable to do that kind of things :

val result= CompletableFuture<String>()
        eventBus.consumer<context.Context>(eventName, this).completionHandler { 
            if(it.succeeded()){
                <http://logger.info|logger.info>("Register ${this::class.simpleName} for event $eventName")
                result.complete(this::class.simpleName)
            }else{
                logger.error("Unable to register ${this::class.simpleName} for event $eventName")
                result.completeExceptionally(UnableToRegisterServiceTaskException())
            }            
        }
        return result

uli

10/13/2017, 12:08 PM

Take a look at Kotlin coroutines. It typically enables you to write clean, sequential code for your concurrent tasks

View count: 2