kotlinlang #getting-started

if(bridgeName == null || bridgeName.isEmpty()) {
			errors.put("add-search-name","Name must not be blank")
		} else {
			if(4 > bridgeName.length) {

			}

works fine, but if I replace the if condition with

if(bridgeName.isNullOrEmpty())

the name length check isn't null safe.

ar-g

08/11/2017, 5:17 AM

Why use backing field and not name of property?

class User(val name: String) {
    var address: String = "unspecified"
        set(value: String) {
            println(address)//works
            address = value//doesn't work
        }
}

lovis

08/11/2017, 11:13 AM

interestingly, if you write

if(long.equals(int)) {
  ...		
}

the IDE suggests to replace it with

==

, even though that doesn’t work 🙈

mquigley

08/11/2017, 6:25 PM

Can anyone explain why the literal

0xAABBCCDD_11223344L

cannot exist in Kotlin? Neither can the value of

Long.MIN_VALUE

, which is actually represented by

-9223372036854775807L - 1L

gaurav9822

08/12/2017, 5:47 AM

Want to learn kotlin

:kotlin: 4

08/13/2017, 4:00 AM

Hi All ... I am Kotlin newbie though programing in java since last 15 years .....and Angular Js ...I have few basic questions we are majorly using angular js /type script ...does kotlin has any bridge for that ..ideas around how to leverage existing angular code with kotlin ?

rebcabin

08/13/2017, 4:11 PM

Question:

count()

versus

size

for collections? Seems there are two ways to get the number of elements in a collection:

count()

called without a predicate argument and

size

, looks like a field, attribute, property. Any reason to prefer one over the other?

jimn

08/14/2017, 6:11 AM

anyone awake?

😴 1

arekolek

08/14/2017, 9:41 AM

But you can have more than one companion object, right? I guess if you can’t impose requirements on properties, then you can’t on companion objects.

08/14/2017, 2:08 PM

can you show the code for

missingParamError

and

incorrectPassword

, and what the similarity/differences between them are?

bachhuberdesign

08/15/2017, 1:50 AM

What is a good way to get around not being able to use reified type parameters in an interface? I want to have a method like

override inline fun <reified T> foo(key: String, value: T): T {
    }

but it's not possible since you can't

inline

an interface function

raul782

08/15/2017, 3:07 AM

Hi guys! I haven't found any implementation of a json-schema-form in kotlin?, do you know if there is one available?

karelpeeters

08/15/2017, 9:45 AM

Yup, while should work.

karelpeeters

08/15/2017, 10:21 AM

You can a sequence to avoid creating a temporary

List

if you're going with

forEach

👍 1

matthew

08/15/2017, 5:57 PM

something with

fold

maybe?

oday

08/15/2017, 8:28 PM

is there a way that I can refer to a Pair’s

first

and

second

by something custom?

oday

08/16/2017, 8:14 AM

what do you guys use for testing?

menegatti

08/16/2017, 9:53 AM

data.groupBy { it[0] }.mapValues { (_, value) -> value.map { it[1] } }

👍 2

delater

08/17/2017, 9:38 AM

I would like to have default return like in java in kotin but when's else doesnt do the thing as it has to be in separate case

oday

08/17/2017, 1:26 PM

how can I break from a foreach 😮

diesieben07

08/17/2017, 5:49 PM

Or just do a nullcheck on the result of

get

instead of the

containsKey

, saves you one hash lookup as well.

darkmoon_uk

08/17/2017, 10:06 PM

Any 'standard advice' for 'Kotling Plugin Update not installed' on Android Studio? It downloads it but fails to install. I checked the logs, no reference to it. My project deps. are already 1.1.4.

mcscruff

08/18/2017, 12:17 AM

hi all, im new to kotlin, and trying to read a JSON file, i have seen the klaxon lib, but how do i add it to my project

Juan

08/18/2017, 4:16 AM

Hello, Could you please explain me what's the companion object intended for?

techie01

08/18/2017, 11:59 AM

what is difference between arraryListOf() and listOf()

dathoang.se

08/20/2017, 8:21 AM

@qwert_ukg not related to your question. But you’re violating “Single Responsibility Principle” because you put two distinct responsilities into a single object, NotificationRespository should only be responsible of storing & loading data. The responsibility of sending notification should be delegated to other objects.

oday

08/20/2017, 8:40 PM

i get a randomblock, the shape, and use its name to feed to the move function so it knows at which cell locations to increment, and eventually redraw, therefore moving the current shape

benleggiero

08/21/2017, 3:25 AM

Why won't this compile?

class Foo(var values: MutableList<String>)

class Bar(var foo: Foo) {
    fun bar() {
        foo.values += "Baz"
    }
}

benleggiero

08/21/2017, 4:16 AM

And why won't this compile either?

class Foo(val bars: Map<Int, Bar<*>>) {
    
    fun <Baz> qux(baz: Baz) {
        val bar2 = bars[2]!!
        bar2.bazes += baz
    }
    
    interface Bar<Baz> {
        var bazes: MutableList<Baz>
    }
}

Title

benleggiero

08/21/2017, 4:16 AM

And why won't this compile either?

class Foo(val bars: Map<Int, Bar<*>>) {
    
    fun <Baz> qux(baz: Baz) {
        val bar2 = bars[2]!!
        bar2.bazes += baz
    }
    
    interface Bar<Baz> {
        var bazes: MutableList<Baz>
    }
}

karelpeeters

08/21/2017, 7:31 AM

Read this: https://kotlinlang.org/docs/reference/generics.html#type-projections

benleggiero

08/21/2017, 1:24 PM

Thanks! I'm still not used to there being useful existing knowledge about Kotlin compiler errors :P

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