Kotlin Multiplatform library

Use the lib product type in a module to build a Kotlin Multiplatform library.

Using IntelliJ IDEA?

Make sure to install the Kotlin Multiplatform plugin to get proper support for Kotlin Multiplatform.

Module layout

Here is an overview of the module layout for a KMP library:

my-module/
├─ resources/       # common resources, used in all targets
├─ resources@ios/   # resources that are only available to the iOS code
├─ resources@jvm/   # resources that are only available to the JVM code
├─ src/             # common code, compiled for all targets
│  ├─ main.kt
│  ╰─ util.kt # (1)!
├─ src@native/      # code to be compiled for all native targets
├─ src@apple/       # code to be compiled for all Apple targets
├─ src@ios/         # code to be compiled only for iOS targets
│  ╰─ util.kt # (2)!
├─ src@jvm/         # code to be compiled only for JVM targets
│  ├─ util.kt
│  ╰─ MyClass.java # (3)!
├─ test/            # common tests, compiled for all targets
│  ╰─ MainTest.kt   
├─ test@ios/        # tests that are only run on iOS simulator
│  ╰─ SomeIosTest.kt
├─ test@jvm/        # tests that are only run on JVM
│  ╰─ SomeJvmTest.kt
├─ testResources/       # common test resources, used in all targets
├─ testResources@ios/   # test resources that are only available to the iOS code
├─ testResources@jvm/   # test resources that are only available to the JVM code
╰─ module.yaml

1. This file may define expect declarations to be implemented differently on different platforms.
2. This file defines the actual implementations corresponding to the expect declarations from src.
3. It's ok to have Java sources in JVM-only source directories.

Read more about multiplatform topics in the general Multiplatform modules section.