Kotlin Multiplatform for Android Developers: Sharing Code with iOS Without Starting Over (Paperback) (ISBN-13: 9798176497120)

Kotlin Multiplatform for Android Developers
Sharing Code with iOS Without Starting Over

You already know Kotlin. You write your ViewModels in it, your Compose UI in it, maybe your Gradle scripts in it too. This book shows you how to take that same language somewhere it's never run for you before - inside an iOS app - without learning Swift from scratch or rewriting your business logic twice.

Most Kotlin Multiplatform books stop at sharing a data class and call it a day. This one doesn't. It follows a single shared module all the way to a real, shippable app: from your first expect/actual declaration through networking, persistence, dependency injection, reactive UI, offline-first sync conflict resolution, dual-toolchain CI/CD, and two app store submissions.

Who this is for
You should already be comfortable writing Android apps in Kotlin. No iOS or Swift background required - each chapter builds the foundation the next one needs, and platform-specific concepts are explained exactly when you reach them, not assumed upfront.

What you'll build
Every chapter adds to one capstone project - an offline-first Expense/Budget Tracker - instead of scattering disposable code snippets. By the final chapter you'll have a production-shaped app complete with a pending-sync queue, retry/backoff behavior, and a deployment checklist for both stores.

What's inside:

• The expect/actual mechanism, source set hierarchy, and shared clean architecture
• Networking with Ktor Client and local persistence with Room KMP, SQLDelight, and DataStore
• Dependency injection with Koin across platforms
• Coroutines, Flow, and Swift interop - including SKIE and JetBrains' native Swift export
• Reactive UI with Compose Multiplatform (plus the native Compose + SwiftUI alternative)
• Platform-specific features: camera, location, biometrics, notifications, and permissions
• Testing across two runtimes, and debugging shared code from Xcode
• CI/CD pipelines that span Linux and macOS runners
• Publishing a KMP library to Maven Central and Swift Package Manager
• KMP beyond mobile: desktop, web (Kotlin/Wasm), and a full-stack Ktor backend
• Migrating an existing Android app to KMP, module by module, without breaking production
• A complete, end-to-end capstone build with a real deployment checklist for both app stores

What makes it different
Most resources treat multiplatform as a toy example. This one treats it as a production decision - including the parts that usually get skipped: testing strategy, CI/CD for two toolchains, library publishing, and incremental migration. It's also honest about the ground shifting under KMP: fast-moving specifics like library versions and JetBrains roadmap items are flagged as a snapshot to verify, not permanent fact.

How to use it
Build the capstone as you go - don't just read it. By Chapter 21, everything comes together into one coherent app, including the unglamorous parts real apps need to ship.