Can someone review my code? Just started learning Kotlin this morning, so decided to port over some existing code... https://github.com/acz13/anagrams/tree/kotlin-rough/kotlin

How to release reference explicitly for garbage collection / memory leak prevention purposes, like

context = null

, for Non-Nullable types? Is it impossible?

Hi. Is there a way to iterate all the components of a data class?

how to declare mutable map inside mutable map

hi there I am trying to use the gradle kotlin dsl and define properties in the following way:

var kotlin_version by extra { "1.1.60" }

and I am getting an unresolved reference 😞 even though I have seen some examples that do that instead I have to do this:

var kotlin_version: String by extra
kotlin_version = "1.1.60"

am I doing something wrong?

Hi all, I'm new to Kotlin, is there any way to execute code during construction of a data class, I want to call a function on the value as it's being passed into the constructor

Hey guys, I'm having an issue for the following snippets. One crashes, the other doesn't crash.

val bufferedImgFile: BufferedImage = ImageIO.read(File(filePath))
val imageMatrix: Array<IntArray> = Array(height) { IntArray(width) }
(0..(bufferedImgFile.height - 1)).map { hgt ->
        (0..(bufferedImgFile.width - 1)).map { wdt ->
          imageMatrix[hgt][wdt] = bufferedImgFile.getRGB(hgt, wdt)
        }
      }

And

val bufferedImgFile: BufferedImage = ImageIO.read(File(filePath))
val imageMatrix: Array<IntArray> = Array(height) { IntArray(width) }
async {
        (0..(bufferedImgFile.height - 1)).map { hgt ->
          async {
            (0..(bufferedImgFile.width - 1)).map { wdt ->
              data[hgt][wdt]= bufferedImgFile.getRGB(hgt, wdt)
            }
          }
        }
      }

The former would crash with an

ArrayOutOfBoundsException

, the later doesn't crash and completes. Please why is this so?

Hi.

shr

is not resolved in the above function

Hello, I’m playing around with

detekt

and wanna write custom rules for android (e.g. ignore UnsafeCast for

context.getSystemService

), so a bit messy with AST and

compiler-embedable

module. Could anyone provide link to some tutorial or smth to understand basics of

ASTNode

parsing: e.g. how to get method body properly or get variable type, etc. Thanks!

error()

looks good. But we're all in agreement that this is a bit weird, right? Would it be reasonable to file an issue on the compiler, to get some kind of official opinion on whether or not it works as intended?

str

is an implicitly predefined variable

Hi folks, I was wondering… What’s the real disadvantages of using inline functions in Kotlin?

why !! operator exists? Why is it needed? Is there some really good reason?

Hi guys, I'm a newcomer to kotlin and I've been working through the Kotlin in Action book. I'm currently on chapter 6.3.5 and I don't quite get this snippet:

>>> val letters = Array(26) { i -> ('a' + i).toString() }
>>> println(letters.joinToString(""))
abcdefghijklmnopqrstuvwxyz

What exactly is

'a' + i

? I've done a little bit of testing and depending on

i

it will return a character. For example:

println('a' + 2) 
c

It seems very basic but I can't find any more detail explanation for this.

What would you suggest I do for testing my code, then?

This message was deleted.

what's the most straight-forward way to do unit tests with kotlin (non-android standalone app)? preferably with a low dependency footprint. I tried doing spek and following its guides, but after installing a bunch of things including the idea plugin, it's still not running properly w/ idea

can I directly remove an element from

data.requests

with

map

instead of using the

if

at the end?

val rq = data.requests.find{ it.id == which && it.loaded }
        if(rq != null){
            val sc = rq.scene
            if (--rq.refCnt == 0)  data.requests.remove(rq)
            return sc
        }

This message was deleted.

Ohhh..So there is one companion object for all the class objects

use whateverLabel@ just before bracket

I am not an expert on generics and I like that we can reify generics in case of inline functions. Why can't Kotlin reify all other generics as well though? Just fake it by passing an extra parameter of type Class to any generic method?

Hi friends, I am learning Android and I also want to learn kotlin at the same time... Till now I have not worked on a single line of code in kotlin... Plz suggest me how to start code in kotlin..

Can Kotlin implement the same interface (with different generic types) multiple times? After some experiments, I guess not. If that's true, how can I work around it?

Found it - https://antonioleiva.com/sealed-classes-kotlin/

Kotlin doesn't use

void

or

Void

, it uses

Unit

. You want

logic: (g: Graphics) -> Unit

Hi. How can I pass a member function as an argument to a function that accepts a interface? Here's my attempts:

interface Consumer<T> {

    fun consume(item: T)
}

class SomeClass {

    fun processInteger(integer: Int) {

        println("I got ${integer}")
    }
}

fun invokeConsumerFunction(consumer: Consumer<Int>) {

    consumer.consume(123)
}

fun main(args: Array<String>) {

    val obj = SomeClass()

    // Attempts, neither of them compiles
    invokeConsumerFunction(obj.processInteger)
    invokeConsumerFunction({item -> obj.processInteger(item)})
}

this raw string syntax is a rare thing from kotlin that i don’t quite like - it looks tediously long. i’d much prefer the typescript backtick syntax, but unfortunately the backtick was already taken for escaping identifiers using keywords

Java has it I think in

java.lang.Character

, not sure though.