Distribute Kotlin Library

Release a library using the plugin

We can distribute to other users a Kotlin library using native or third-party dependency, some requirements are necessary for Apple targets.

Requirement

The user must :

• add the same native dependency used by the Kotlin library to his Xcode project.
• use the same version as the library use.

It will fix issues with linking, missing resources, App Store compliance, and more.

Note

The user doesn't have access to the Kotlin library source code, which is great!

Example

A Compose Multiplatform Component library using a native video player.

commonMain/kotlin/KmpPlayer.kt

@Composable
public expect fun KmpPlayer(modifier: Modifier = Modifier, url: String)

Android

For Android, it uses Exoplyer.

Gradle

library/build.gradle.kts

androidMain.dependencies {
    implementation(libs.media3.exoplayer)
    implementation(libs.media3.exoplayer.dash)
    implementation(libs.media3.ui)
}

AndroidMain

androidMain/kotlin/KmpPlayer.kt

@Composable
public actual fun KmpPlayer(modifier: Modifier, url: String) {

    val context = LocalContext.current

    // Initialize ExoPlayer
    val exoPlayer = ExoPlayer.Builder(context).build()

    val mediaSource = remember(url) {
        MediaItem.fromUri(url)
    }


    LaunchedEffect(url) {
        exoPlayer.setMediaItem(mediaSource)
        exoPlayer.prepare()
    }

    // Manage lifecycle events
    DisposableEffect(Unit) {
        onDispose {
            exoPlayer.release()
        }
    }

    AndroidView(
        factory = { ctx ->
            PlayerView(ctx).apply {
                player = exoPlayer
            }
        },
        modifier = modifier
    )
}

iOS

For iOS, it uses KSPlayer, it's a pure Swift library.

Gradle

library/build.gradle.kts

swiftPackageConfig {
    create("appleDeps") {
        minIos = "13.0"
        minMacos = "10.15"
        minTvos = "13.0"
        minWatchos = "2.0"
        dependency(
            SwiftDependency.Package.Remote.Branch(
                url = URI("https://github.com/kingslay/KSPlayer"),
                products = {
                    add("KSPlayer")
                },
                branch = "main"
            ),
        )
    }
}

Bridge

src/swift/appleDeps/MEPlayerController.swift

import Foundation
import KSPlayer

@objcMembers public class MEPlayerController: NSObject {
     private let player = IOSVideoPlayerView()

    override init() {
       super.init()
       KSOptions.secondPlayerType = KSMEPlayer.self
       player.delegate = self
       player.autoresizingMask = [.flexibleWidth, .flexibleHeight]
       player.contentMode = .scaleAspectFill
    }

    public func setMediaItem(videoUrl: URL) {
       player.set(
          url: videoUrl,
          options: KSOptions()
      )
    }

    public var playerView: NSObject {
       player
    }

    public func releasePlayer() {
       player.resetPlayer()
       player.removeFromSuperview()
    }
}

IOSMain

iosMain/kotlin/KmpPlayer.kt

import appleDeps.MEPlayerController

@Composable
public actual fun KmpPlayer(modifier: Modifier, url: String) {

    val playerController = MEPlayerController()

    val mediaSource = remember(url) {
        NSURL.URLWithString(url)
    }

    LaunchedEffect(url) {
        if (mediaSource == null) {
            throw Exception("Bad input URL")
        }
        playerController.setMediaItemWithVideoUrl(videoUrl = mediaSource)
    }

    DisposableEffect(Unit) {
        onDispose {
            playerController.releasePlayer()
        }
    }

    UIKitView(
        factory = {
            playerController.playerView() as UIView
        },
        modifier = modifier,
        update = {
        }
    )
}

Requirement

The setup guide of your library must contain the rule that KSPlayer package must be added to his Xcode project with the explicit version.

Sample

The sample is available.

• Run the command ./gradlew publishToMavenLocal --no-configuration-cache on the repository root.
• Open the project sampleApp and test the application