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Kotlin Multiplatform Compose — Complete Guide

DodaTech Updated 2026-06-24 2 min read

In this tutorial, you'll learn about Kotlin Multiplatform Compose. We cover key concepts, practical examples, and best practices.

The Problem

Your Compose Multiplatform project doesn't render on iOS, or you're using Android-specific composables that don't exist on iOS.

Wrong Approach ❌

// Using Android-only composables
@Composable
fun MyScreen() {
    // AndroidView — doesn't exist on iOS!
    AndroidView(factory = { View(it) }) { }
}

Output: Compilation error on iOS target. Shared UI doesn't work.

Right Approach ✅

// build.gradle.kts (shared module)
plugins {
    kotlin("multiplatform")
    id("org.jetbrains.compose") version "1.6.10"
    id("org.jetbrains.kotlin.plugin.compose")
}

kotlin {
    androidTarget()
    listOf(iosX64(), iosArm64(), iosSimulatorArm64()).forEach { target ->
        target.binaries.framework {
            baseName = "shared"
            isStatic = true
        }
    }

    sourceSets {
        commonMain.dependencies {
            implementation(compose.runtime)
            implementation(compose.foundation)
            implementation(compose.material3)
            implementation(compose.ui)
        }
    }
}

// commonMain — shared composables
@Composable
fun App() {
    MaterialTheme {
        var count by remember { mutableStateOf(0) }
        Scaffold(
            topBar = { TopAppBar(title = { Text("KMP Compose") }) },
            floatingActionButton = {
                FloatingActionButton(onClick = { count++ }) {
                    Icon(Icons.Default.Add, "Add")
                }
            }
        ) { padding ->
            Column(
                modifier = Modifier.padding(padding).fillMaxSize(),
                horizontalAlignment = Alignment.CenterHorizontally,
                verticalArrangement = Arrangement.Center
            ) {
                Text("Count: $count", style = MaterialTheme.typography.headlineLarge)
                Button(onClick = { count = 0 }) { Text("Reset") }
            }
        }
    }
}

// platform-specific entry points
// androidMain
class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent { App() }
    }
}

// iosMain
import androidx.compose.ui.window.ComposeUIViewController
fun MainViewController() = ComposeUIViewController { App() }

Output: Shared Compose UI renders on both Android and iOS.

Prevention

  • Use only multiplatform-compatible Compose APIs (compose.foundation, compose.material3).
  • Use expect/actual for platform-specific UI (e.g., camera preview, maps).
  • Use org.jetbrains.compose plugin, not Android-only compose plugin.
  • Test UI on both platforms.

Common Mistakes with multiplatform kmp compose

  1. Mixing let bindings with <- bindings in do notation, producing type errors
  2. Overlapping type class instances that cause GHC to reject the program with ambiguous dispatch errors
  3. Non-exhaustive pattern matches that compile with warnings then crash at runtime

These mistakes appear frequently in real-world KOTLIN code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ

### What Compose APIs are available in KMP?

compose.runtime, compose.foundation, compose.material3, compose.ui, and compose.animation are all multiplatform. Platform-specific APIs like AndroidView are not.

### How do I use platform-specific UI in shared code?

Use expect composables or provide UI components via dependency injection. For example, @Composable expect fun CameraPreview() with platform actuals.

### Can I use third-party Compose libraries?

Only if they support KMP. Libraries like compose-richtext and kamel (image loading) have KMP support. Check library documentation for KMP compatibility.

← Previous Kotlin Multiplatform iOS — Complete Guide Next → Kotlin Multiplatform Serialization — Complete Guide

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