Extremely minimal Compose Multiplatform sample that demonstrates use of on-device AI on iOS and Android. Specifically it uses Foundation Model Framework on iOS and MLKit Prompt API on Android.

In following codePromptApi is a Kotlin interface that's implemented by a Swift class on iOS and a Kotlin one on Android. The Swift implementation is passed down to shared KMP code and invoked from the Compose Multiplatform code if running on iOS.

Right now the respective iOS and Android implementations are assigned to a top level promptApi variable. This is a somewhat hacky solution for now for the sake of simplicity....there's a similar requirement in many of the other samples I have and in those cases the implementation is set in such a way that it becomes part of the object graph of particular DI framework being used.

iOS (Swift)

import FoundationModels

class PromptApiIos: PromptApi {
    
    func generateContent(prompt: String) async throws -> String? {
        let session = LanguageModelSession()
        let response = try await session.respond(to: prompt)
        return response.content
    }
}

Android (Kotlin)

import com.google.mlkit.genai.prompt.Generation

class PromptApiAndroid: PromptApi {
    private val generativeModel = Generation.getClient()

    override suspend fun generateContent(prompt: String): String? {
        val response = generativeModel.generateContent(prompt)
        return response.candidates.firstOrNull()?.text
    }
}

Project structure

• composeApp — shared KMP library (com.android.kotlin.multiplatform.library) with the Compose Multiplatform UI, the PromptApi interface, and the Android PromptApiAndroid implementation; exports the ComposeApp framework to iOS.
• androidApp — Android application module (MainActivity, manifest, launcher resources) that depends on composeApp.
• iosApp — Xcode project with the Swift PromptApiIos implementation.

The module split (rather than a single composeApp app module) is required by AGP 9, which makes the Android application plugin incompatible with the Kotlin Multiplatform plugin in the same module.