https://github.com/davidmhewitt/kotlinsample
Template project for building a GTK3 Kotlin/Native app against the elementary Flatpak runtime
https://github.com/davidmhewitt/kotlinsample
elementaryos gtk3 kotlin kotlin-native
Last synced: about 1 year ago
JSON representation
Template project for building a GTK3 Kotlin/Native app against the elementary Flatpak runtime
- Host: GitHub
- URL: https://github.com/davidmhewitt/kotlinsample
- Owner: davidmhewitt
- Created: 2022-01-05T00:25:01.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2022-01-05T22:17:36.000Z (over 4 years ago)
- Last Synced: 2025-04-20T23:32:32.231Z (about 1 year ago)
- Topics: elementaryos, gtk3, kotlin, kotlin-native
- Language: Kotlin
- Homepage:
- Size: 67.4 KB
- Stars: 13
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# GTK3 Kotlin/Native Sample
This is a working example of how to write and build a GTK3 application in Kotlin/Native. It includes a Flatpak manifest that successfully builds the application against the elementary Flatpak runtime.
The [GTK-KT](https://gitlab.com/gtk-kt/gtk-kt/-/tree/gtk-3) library is used to wrap GTK in a nice Kotlin-like API. If you wish to build this project locally, you will first need to build and install GTK-KT to your local Maven repository as per the instructions in its README.
Most of the files here are the standard Kotlin/Native template files as produced by [IntelliJ IDEA](https://www.jetbrains.com/idea/). The following customizations have been made:
### `maven-modules.json`
This is generated by [`flatpak-maven-generator`](https://github.com/flatpak/flatpak-builder-tools/pull/253) with the following command:
```
flatpak-maven-generator -r https://plugins.gradle.org/m2/ org.jetbrains.kotlin.multiplatform:org.jetbrains.kotlin.multiplatform.gradle.plugin:1.5.0 org.jetbrains.kotlin:kotlin-stdlib:1.5.21 org.jetbrains.kotlin:kotlin-reflect:1.5.21 org.jetbrains.kotlinx:kotlinx-coroutines-core:1.5.0-native-mt org.jetbrains.kotlinx:kotlinx-coroutines-core-linuxx64:1.5.0-native-mt org.jetbrains.kotlinx:atomicfu:0.16.1
```
This JSON file instructs `flatpak-builder` to download the requested Maven artifacts (and their recursive dependencies) into a local Maven repository. As the `flatpak-builder` sandbox does not allow internet access, the Gradle build scripts cannot download dependencies, so we have to pre-provide them in this way.
### `build.gradle.kts`
The following section was added to the standard IDEA template:
```
repositories {
mavenCentral()
mavenLocal()
maven() { url = uri("/app/maven-local") }
}
```
This allows the build to work locally (outside the Flatpak sandbox), by using `mavenLocal` for GTK-KT and `mavenCentral` on the internet for other dependencies. The `/app/maven-local` line allows the build inside the sandbox to find dependencies by using the mirrored maven repository created by the JSON file above.
### `settings.gradle.kts`
The following section was added to the standard IDEA template:
```
pluginManagement {
repositories {
maven(url = "/app/maven-local")
gradlePluginPortal()
}
}
```
Again, this allows Gradle to find plugins in the local Maven repository inside the sandbox, this wouldn't be necessary if not building as a Flatpak.
### `local-maven-repository.patch`
This is a patch applied to `gtk-kt` during a Flatpak build to allow it to find its Maven artifacts.
### `io.github.davidmhewitt.KotlinSample.yml`
This is the Flatpak build manifest. In order:
* The `kotlin-native` module downloads and unpacks the Kotlin Native compiler to `/app/kotlin-native`. This is entirely cleaned up after the build has finished to make the resulting Flatpak as small as possible.
* The `konan-deps` module downloads dependencies of the Kotlin compiler. This is essentially a full GCC/Clang/LLVM toolchain. This is fairly inefficient use of bandwidth during the build as these tools could be available in the Flatpak SDK, but it seems Kotlin does not fully support using the host's toolchain yet. This is entirely cleaned up after the build.
* The `maven-modules` module downloads a local mirror of the artifacts required from Maven repos to `/app/maven-local` as specified in the JSON file. This repository is cleaned up after the build.
* The `gtk-kt` module clones and builds `gtk-kt` and publishes it to the `/app/maven-local` repository. We're selective about which subprojects we build to save time. This is cleaned up after the build.
* Finally, the `sample` module builds our application against the published `gtk-kt` module and copies the executable to the `/app/bin` folder as expected by Flatpak.