Introduction:
As the Android development ecosystem continues to shift toward declarative programming, Jetpack Compose stands out as a modern alternative to traditional XML layouts. Many developers with existing XML-based apps face the challenge of transitioning to Compose UI, and beyond that, expanding their apps for multiplatform use. In this post, we’ll walk through the process of converting a Kotlin XML Android project to Jetpack Compose and explore how to prepare it for Kotlin Multiplatform.
Why Transition to Jetpack Compose and Multiplatform?
- Reduces boilerplate code
- Streamlines UI development with a declarative syntax
- Enables UI and business logic reuse across Android, iOS, Desktop, and more
- Offers better performance and maintainability
Step-by-Step Migration Guide
1. Modularize Your Project
Begin by separating your app into modules:
- UI module (XML-based)
- Business logic module
This makes it easier to isolate logic you’ll reuse across platforms.
2. Gradual Integration of Jetpack Compose
You don’t need a complete rewrite. Use ComposeView to embed Compose UI inside existing XML layouts. Replace one screen at a time.
val composeView = ComposeView(context).apply { setContent { MyComposableUI() } }
3. Move Business Logic to Shared Module
To enable multiplatform support, refactor your business logic into a shared Kotlin module using Kotlin Multiplatform conventions. This shared codebase can then be used across Android, iOS, Desktop, etc.
4. Use JetBrains’ Compose Multiplatform
Compose Multiplatform extends the Compose framework beyond Android. With it, you can target:
- Android
- iOS (in experimental phases)
- Desktop
- Web (under development)
This gives your app maximum reach with minimum duplication.
Architecture Shift Overview
| Layer | Traditional XML App | Compose Multiplatform |
|---|---|---|
| UI | XML + Activity/Fragment | Kotlin @Composable functions |
| Logic | Kotlin (platform specific) | Shared Kotlin module |
| Navigation | XML-based NavController | Compose Navigation |
| Platform support | Android only | Android, Desktop, iOS |
Conclusion:
Migrating to Jetpack Compose isn’t just a visual upgrade—it’s an investment in scalability, maintainability, and reach. With Kotlin Multiplatform and Compose, your app becomes future-proof and adaptable across various devices and platforms. If you’re still tied to XML, now’s the perfect time to consider an upgrade and ride the wave of modern development.
