/kotlinx.coroutines

Library support for Kotlin coroutines

Primary LanguageKotlinApache License 2.0Apache-2.0

kotlinx.coroutines

official JetBrains project GitHub license Download Kotlin Slack channel

Library support for Kotlin coroutines with multiplatform support. This is a companion version for the Kotlin 1.4.30 release.

suspend fun main() = coroutineScope {
    launch { 
       delay(1000)
       println("Kotlin Coroutines World!") 
    }
    println("Hello")
}

Play with coroutines online here

Modules

Documentation

Using in your projects

The libraries are published to kotlinx Bintray repository, linked to JCenter and pushed to Maven Central.

Maven

Add dependencies (you can also add other modules that you need):

<dependency>
    <groupId>org.jetbrains.kotlinx</groupId>
    <artifactId>kotlinx-coroutines-core</artifactId>
    <version>1.4.3</version>
</dependency>

And make sure that you use the latest Kotlin version:

<properties>
    <kotlin.version>1.4.30</kotlin.version>
</properties>

Gradle

Add dependencies (you can also add other modules that you need):

dependencies {
    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.4.3'
}

And make sure that you use the latest Kotlin version:

buildscript {
    ext.kotlin_version = '1.4.30'
}

Make sure that you have mavenCentral() in the list of repositories:

repository {
    mavenCentral()
}

Gradle Kotlin DSL

Add dependencies (you can also add other modules that you need):

dependencies {
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.4.3")
}

And make sure that you use the latest Kotlin version:

plugins {
    kotlin("jvm") version "1.4.30"
}

Make sure that you have mavenCentral() in the list of repositories.

Android

Add kotlinx-coroutines-android module as a dependency when using kotlinx.coroutines on Android:

implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.4.3'

This gives you access to the Android Dispatchers.Main coroutine dispatcher and also makes sure that in case of a crashed coroutine with an unhandled exception that this exception is logged before crashing the Android application, similarly to the way uncaught exceptions in threads are handled by the Android runtime.

R8 and ProGuard

R8 and ProGuard rules are bundled into the kotlinx-coroutines-android module. For more details see "Optimization" section for Android.

Avoiding including the debug infrastructure in the resulting APK

The kotlinx-coroutines-core artifact contains a resource file that is not required for the coroutines to operate normally and is only used by the debugger. To exclude it at no loss of functionality, add the following snippet to the android block in your Gradle file for the application subproject:

packagingOptions {
  exclude "DebugProbesKt.bin"
}

Multiplatform

Core modules of kotlinx.coroutines are also available for Kotlin/JS and Kotlin/Native.

In common code that should get compiled for different platforms, you can add a dependency to kotlinx-coroutines-core right to the commonMain source set:

commonMain {
    dependencies {
        implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.4.3")
    }
}

No more additional dependencies are needed, platform-specific artifacts will be resolved automatically via Gradle metadata available since Gradle 5.3.

Platform-specific dependencies are recommended to be used only for non-multiplatform projects that are compiled only for target platform.

JS

Kotlin/JS version of kotlinx.coroutines is published as kotlinx-coroutines-core-js (follow the link to get the dependency declaration snippet) and as kotlinx-coroutines-core NPM package.

Native

Kotlin/Native version of kotlinx.coroutines is published as kotlinx-coroutines-core-$platform where $platform is the target Kotlin/Native platform. List of currently supported targets.

Only single-threaded code (JS-style) on Kotlin/Native is supported in stable versions. Additionally, a special -native-mt version is released on a regular basis, for the state of multi-threaded coroutines support please follow the corresponding issue for the additional details.

Since Kotlin/Native does not generally provide binary compatibility between versions, you should use the same version of the Kotlin/Native compiler as was used to build kotlinx.coroutines.

Building and Contributing

See Contributing Guidelines.