map

List<UserApi>

List<User>

override fun onBackPressed() {
        drawer?.run {
            if (!isDrawerOpen) {
                openDrawer()
                this
            } else null
        } ?: super.onBackPressed()
    }

import java.security.MessageDigest
fun foo(rp: String) {
    return bar(rp)
}
private fun bar(rp: String): ByteArray {
    return MessageDigest.getInstance("SHA-256").digest(rp.toByteArray())
}

Intrinsics.checkParameterIsNotNull

foo

if (rpId ==null)

bar

TypeCastException

IllegalArgumentException

Command+LMB

Ctrl+B

check

fun <T> Sequence<T>.takeWhileInclusive(pred: (T) -> Boolean): Sequence<T> = take(count(pred) + 1)

var a: String? = null

    var b: String = a as String

fun main(args: Array<String>) = runBlocking<Unit> {
    val startTime = System.currentTimeMillis()
    val job = launch {
        var nextPrintTime = startTime
        var i = 0
        while (i < 5) { // computation loop, just wastes CPU
            // print a message twice a second
            if (System.currentTimeMillis() >= nextPrintTime) {
                println("I'm sleeping ${i++} ...")
                nextPrintTime += 500L
            }
        }
    }
    delay(1300L) // delay a bit
    println("main: I'm tired of waiting!")
    job.cancelAndJoin() // cancels the job and waits for its completion
    println("main: Now I can quit.")
}

fun main(args: Array<String>) = runBlocking<Unit> {
    val job = launch {
        try {
            repeat(1000) { i ->
                println("I'm sleeping $i ...")
                delay(500L)
            }
        } finally {
            println("I'm running finally")
        }
    }
    delay(1300L) // delay a bit
    println("main: I'm tired of waiting!")
    job.cancelAndJoin() // cancels the job and waits for its completion
    println("main: Now I can quit.")
}

val a = com.mycompany.path1.MyEnum.GOOD
val b = com.mycompany.path2.MyEnum.GOOD
if (a == b) {
    println("a == b")
}

Operator '==' cannot be applied to 'com.mycompany.path1.myEnum' and 'com.mycompany.path2.MyEnum'

data class DataSourceResponse(val response: Response)
data class Response(val notifications: List<Notification>)
data class Notification(id: Int)

callback.onDataLoaded(
    paramDataSourceResponse.copy (
        response = paramDataSourceResponse.response.copy (
            notifications = paramDataSourceResponse.response.notifications.filter { check(it) }
        )
    )
)

private fun whenTest(a: Boolean, b: Boolean) = when {
    a && b -> ""
    !a && b -> ""
    a && !b -> ""
    !a && !b -> ""
}

internal

main

test

integrationTest

fun main(args: Array<String>) {
    val wi = WrapInt(1)
    val ws = WrapString("1")
    println(wi)
    println(ws)
}

inline class WrapInt(private val x: Int)
inline class WrapString(private val x: String)

data class

WrapInt(x=1)
1

WrapInt(x=1)
WrapString(x=1)

exists

companion object

Enum.values()

jsonValue