kotlinlang #announcements

hello, I've an issue with parameters visibility and constructors. I google the problem but I wasn't able to find any solution, so given the following code:

class MyAwesomeView: FrameLayout {
	constructor(context: Context?, attrs: AttributeSet? = null) : super(context, attrs)
	constructor(context: Context?, attrs: AttributeSet?, parm1: Int) : super(context, attrs, parm1)
	constructor(context: Context?, attrs: AttributeSet?, parm1: Int, parm2: Int) : super(context, attrs, parm1, parm2)
	
	init {
		context.someMethod(attrs)
	}
}

The init method cannot access attrs, I'm getting "Unresolved reference 'attrs'". Why is that? how can I make init access attrs. Shouldn't be enough by adding attrs to constructors as it is here?

Paul Woitaschek

03/20/2019, 11:55 AM

On a data class, a property is never shown as unused because it's used in toString, equals & hashcode. So when I want to find unsued properties I would manually need to remove the `data`modifier. Is there any way around that?

juliocbcotta

03/20/2019, 2:42 PM

Does using

internal

in my gradle modules classes makes the project compilation time smaller or improves the IDE memory/processor usage? If so, Is there any docs/articles about this?

klizter

03/20/2019, 3:07 PM

Is it possible to create Kotlin

Map

where key is

String

and case insensitive?

amanda.hinchman-dominguez

03/20/2019, 3:11 PM

Oh, hold on. Lists do have that covariance in the interface itself. Nevermind!

Paul Woitaschek

03/20/2019, 4:09 PM

Does someone know which bigger companies use kotlin native for shared logic between iOS and android? I'm advocating for that within my company and would like to quote that we're not the only company doing this on the earth 😉

👍 2

basher

03/20/2019, 9:36 PM

Does the default implementation of a Kotlin object's hashCode work how it does in Java, where it returns some identity hashCode that reflects object ===-type equality?

turansky

03/20/2019, 11:52 PM

What is better pair methor name for

truncate

? https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.math/truncate.html 1.

fraction

fractional

2️⃣ 2

1️⃣ 1

:no_red: 1

Sola

03/21/2019, 9:17 AM

I'm experiencing an unexpected compile error with new inference (

-Xnew-inference

), is this a known issue? (It compiles with old inference implementation, btw)

Ubi

03/21/2019, 9:51 AM

Is it possible to have an inline block of code that returns an object. In the example below you have to “manually” call

invoke()

. Is there any other way to achieve this?

-.kt

Paul Woitaschek

03/21/2019, 11:09 AM

Why are functions like

.sumBy()

not defined on

kotlin.collections.Iterator<T>

too? I'm using android-ktx

fun <T> androidx.collection.SparseArrayCompat<T>.valueIterator(): kotlin.collections.Iterator<T>

and would like to sum the values. As a workaround I can call

toSequence().sumBy { it }

amadeu01

03/21/2019, 12:48 PM

guys, how to you open like a

kotlin repl

but with some library included. Eg: I want to make a test with RxKotlin, but I just want to see the result of something, is that possible to make a import of the library to the repl ?

Ian White

03/21/2019, 1:10 PM

I’m writing an annotation processor using Kapt and KotlinPoet; am I correct in thinking that there is no way to detect nullability on parameterized type values? i.e. I cannot distinguish

myMap: Map<String,Any>

from

myMap: Map<String,Any?>

, because both of those turn into Java

Map<String,Object>

from the standpoint of the annotation processor. Is there any way to distinguish them? As a workaround I’m considering adding an additional annotation

@HasNullValue

but it’s a bit of a hack.

Slackbot

03/21/2019, 4:05 PM

This message was deleted.

karelpeeters

03/21/2019, 5:15 PM

You can't. Chars are primitives and so they don't have an identity (unless there's boxing involved but even then it's still a bad idea to depend on identity anyway). In this case you could check the index instead:

if (indice == composizione.lastIndex)

David Cuesta

03/21/2019, 6:31 PM

hey guys, is there a way of overloading the operator "->"?

🇳🇴 3

ddlucas

03/21/2019, 7:05 PM

@David Cuesta if only they used => instead of >= you could use the compareTo

LeoColman

03/22/2019, 1:17 AM

fun Any?.foo(other: Any?) {
    contract {
        other == null implies (this != null)
    }
}

Guru

03/22/2019, 8:43 AM

according to http://kotlinlang.org coroutineScope{...} will not block the current thread while waiting for all children to complete.

spand

03/22/2019, 8:54 AM

It wont return until all children are complete but the thread is not blocked

klizter

03/22/2019, 8:57 AM

Hey! Is it possible to swap two elements in a mutableList? Can’t find any swap method.

Antanas A.

03/22/2019, 12:01 PM

I think it's better to use "launch" instead of "coroutineScope" in your case

Guru

03/22/2019, 12:26 PM

@Antanas A. - I just shifted my lauch3 just above coroutineScope{...} and it works just fine. But, surprisingly any thing below coroutineScope{...} is never gonna execute...!! It is blocking..! May be its a bug. I have no idea.!

hdarritchon

03/22/2019, 3:45 PM

And do you know if it will be available one day or it’s a limitation of Kotlin ?

liminal

03/22/2019, 4:31 PM

aggregate_function_question.kt

tipsy

03/22/2019, 7:50 PM

is there any way to freeze a java object? i have a framework which exposes a class like this

class Person {
    public int age;
    public String name;
}

and i want to turn it into a

data class(val age: Int, val name: String)

. i know i could write something to convert it, but is there something built-in that can just freeze the object instead?

Slackbot

03/22/2019, 8:53 PM

This message was deleted.

Kirill Zhukov

03/22/2019, 10:58 PM

Or rather, it is, but it has different naming,

BigDecimal#toInt()

which maps to

intValue()

. Curious how this is done.

Hamza

03/23/2019, 5:19 PM

Is it possible to make kotlin able to compile for .NET

🇳🇴 3