Coroutines in Kotlin. Why ?

Coroutines are a powerful feature in Kotlin for writing asynchronous and concurrent code. They provide a way to write asynchronous code in a more sequential and readable manner, avoiding the callback hell that can occur with traditional callback-based approaches.

In Kotlin, coroutines are part of the Kotlin Standard Library and are built on top of the suspend keyword. The suspend keyword is used to mark functions or lambda expressions that can be paused and resumed. Coroutines can be used for both asynchronous programming (such as handling network requests or database queries) and concurrent programming (such as parallel execution of tasks).

Here are some key concepts related to coroutines in Kotlin:

1. Coroutine Scope: Coroutines are typically launched within a specific scope, which defines the lifecycle of the coroutine. The most common scope is the CoroutineScope. The scope is responsible for managing the lifecycle of coroutines and can be used to cancel them when needed.

import kotlinx.coroutines.*

fun main() {
    runBlocking {
        // CoroutineScope for the main function
        launch {
            delay(1000L)
            println("World!")
        }
        println("Hello, ")
    }
}

1. launch() Function: The launch function is used to launch a new coroutine. It is a builder function that takes a coroutine context and a lambda expression with the code to be executed in the coroutine.

import kotlinx.coroutines.*

fun main() {
    runBlocking {
        // CoroutineScope for the main function
        launch {
            delay(1000L)
            println("World!")
        }
        println("Hello, ")
    }
}

1. suspend Function: The suspend keyword is used to mark functions that can be suspended. These functions can be used inside coroutines to perform asynchronous operations without blocking the thread.

suspend fun fetchData(): String {
    delay(1000L)
    return "Data"
}

fun main() {
    runBlocking {
        val result = launch {
            val data = fetchData()
            println("Data: $data")
        }
        result.join()
    }
}

Coroutines in Kotlin provide a more structured and readable way to write asynchronous and concurrent code compared to traditional callback-based approaches. They make it easier to write code that is both efficient and maintainable, especially in scenarios where asynchronous or concurrent programming is required.

References:

1. https://androidauthority.dev/android-kotlin-coroutines

2. https://developer.android.com/kotlin/coroutines