K/N project setup

To start developing a GTK application in Kotlin/Native, you first need to set up a Kotlin/Native project. If you’re already familiar with this, feel free to skip ahead to the Hello World! section.

Gradle is a popular build system used in Kotlin/Native and Kotlin Multiplatform projects, as well as across Java and Android ecosystems. While many IDEs, including IntelliJ IDEA, can generate necessary Gradle files, this tutorial explains how to create them manually for a deeper understanding.

Creating Project Files¶

Create the Project Directory: Inside, create a build.gradle.kts file with the following content:

// build.gradle.kts
plugins {
    kotlin("multiplatform") version "1.8.10"
}

kotlin {
    linuxX64("native") {
        binaries {
            executable()
        }
    }
    sourceSets {
        val nativeMain by getting {
            dependencies {
                // Specify dependencies here
            }
        }
    }
}

tasks.withType<Wrapper> {
    description = "Regenerates the Gradle Wrapper files"
    distributionType = Wrapper.DistributionType.ALL
    gradleVersion = "7.6"
}

Add a Settings File: Create settings.gradle.kts with the following content:

// settings.gradle.kts
pluginManagement {
    repositories {
        gradlePluginPortal()
        mavenCentral()
    }
}

dependencyResolutionManagement {
    repositories {
        mavenCentral()
        mavenLocal()
    }
}

3. Add the Source Directory: Create a src/nativeMain/kotlin directory and inside, add hello.kt with the following code:

// hello.kt
 fun main() {
     println("Hello K/N!")
 }

By convention, source files are located in src/<target name>[Main|Test]/kotlin folders, where <target name> matches the target platform (native in this case).

With these files in place, you’re ready to build the project. First, we need to download the Gradle Wrapper.

Setting Up the Gradle Wrapper¶

The Gradle Wrapper lets you download and run a specific version of Gradle, ensuring consistency across different development environments.

To install the Gradle Wrapper:

Install Gradle via your package manager. On Ubuntu, use:
```
sudo apt install gradle
```
In the project directory, run:
```
gradle wrapper
```
After downloading the Wrapper, you can uninstall Gradle:
```
sudo apt remove gradle
sudo apt autoremove
```

This removes the Gradle binary, but you can still build the project using the Gradle Wrapper.

Building and Running the Application¶

Build the Project: Run this command from the project root:

./gradlew nativeBinaries

This will generate build/bin/native, containing debugExecutable and releaseExecutable directories with the compiled binaries.

Run the Project: Execute the following to run the application:

build/bin/native/debugExecutable/<project_name>.kexe

You should see “Hello K/N!” printed in the terminal.

Opening the Project in an IDE¶

You can open the project in any IDE that supports Gradle. In IntelliJ IDEA:

Go to File | Open…
Select the project directory and click Open.

IntelliJ IDEA should automatically detect it as a Kotlin/Native project.

Note

If you encounter issues, IntelliJ IDEA will display error messages in the Build tab.