Using Kotlin 2.0 for Android Development

Kotlin 2.0 was released in May 2024 and includes many change like Improved Performance, Enhanced Type Inference and Better Coroutines.

Today we’ll take a look a the new language features added.

Context Receivers

Kotlin 2.x allows you to define multiple receivers for a function

class Database {
    fun queryData(): String = "Data from database"
}

class Network {
    fun fetchData(): String = "Data from network"
}

context(Database, Network)
fun getData(): String {
    val dbData = queryData()
    val networkData = fetchData()
    return "$dbData - $networkData"
}

fun main() {
    val database = Database()
    val network = Network()

    with(database) {
        with(network) {
            println(getData())
        }
    }
}

Improved Type Inference

In Kotlin 1.x, type inference doesn’t always work.

val listOfPairs = listOf(Pair(1, "One"), Pair(2, "Two"))

val mapFromList = listOfPairs.associate { pair: Pair<Int, String> ->
    pair.first to pair.second
}

In Kotlin 2.x, it does a much better job.

val listOfPairs = listOf(1 to "One", 2 to "Two")

val mapFromList = listOfPairs.associate { it.first to it.second }

Improved Coroutines

There are some small improvements to coroutines. Here’s the code in Kotlin 1.x

fun main() = runBlocking {
    val deferredResults = listOf(
        async { networkRequest() },
        async { databaseQuery() }
    )

    val results = deferredResults.awaitAll()

    println("Results: $results")
}

Here’s the same code for Kotlin 2.x

fun main() = runBlocking {
    val results = awaitAll(
        async { networkRequest() },
        async { databaseQuery() }
    )

    println("Results: $results")
}

These are some of the changes introduced in Kotlin 2.0. Just these changes make it worth upgrading to this version.

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