55 Kotlin Recipes for Android Programming
55 Kotlin Recipes for Android Programming
Practical Solutions to Common Android Development Problems
About the Book
Master modern Android development with 40+ practical, production-ready recipes that take you from Kotlin fundamentals to advanced architectural patterns.
Stop piecing together fragmented Stack Overflow answers. When you search online for Android solutions, you get contradictory advice from different eras—a 2019 answer with deprecated APIs, a Reddit snippet that works but leaks memory, five "correct" approaches with no guidance on which to choose. What starts as a simple question turns into a 45-minute rabbit hole through 12 browser tabs.
Kotlin Recipes for Android Developers provides you with curated, battle-tested solutions that offer the context Stack Overflow can't provide. Each recipe delivers not just working code, but also guidance on when to use it, why it works, and what pitfalls to avoid—saving you from mistakes that you'd only discover in production.
What You'll Learn:
Starting with essential Kotlin concepts, such as null safety, immutability, and extension functions, you'll quickly move on to Android-specific techniques for managing views, lifecycles, and navigation. The book progresses through core development topics, including state management with sealed classes, networking with Retrofit and coroutines, and data persistence with Room and DataStore.
Advanced chapters cover Jetpack Compose fundamentals, dependency injection with Hilt, clean architecture patterns, and performance optimization. You'll master coroutines and Flow for reactive programming, learn to structure modular projects, and discover how to write testable, maintainable code.
With 55 recipes spanning beginner to advanced topics, this book serves as both a structured learning path and a quick reference for solving real Android development problems the Kotlin way—no hunting, no conflicting opinions, just proven solutions.
Perfect for: Android developers ready to embrace Kotlin's idioms, Java developers making the switch, and anyone looking to modernize their Android development skills with current best practices.
About the Author
Table of Contents
- Kotlin Basics for Android
- Recipe 1: val vs. var keyword. Which one to use?
- Recipe 2: Null safety with ?, !!, and safe calls.
- Recipe 3: Default parameters & named arguments (reduce overloads)
- Recipe 4: Using string templates instead of concatenation.
- Recipe 5: Extension functions for cleaner utilities.
- Working with Android Views & Lifecycle
- Recipe 6: Safe Fragment View Binding (avoid leaks)
- Recipe 7: Using by lazy for view and resource initialization.
- Recipe 8: Lifecycle-aware coroutines with lifecycleScope.
- Recipe 9: Passing data between Activities/Fragments safely with Bundles.
- Recipe 10: Toasts & Snackbars as one-shot events (SharedFlow)
- Data & State Management
- Recipe 11: Data classes with copy() for immutability
- Recipe 12: Sealed classes for UI states (Loading, Error, Success)
- Recipe 13: Safe Args in Navigation (type-safe arguments)
- Recipe 14: Persisting small UI state with SavedStateHandle
- Recipe 15: SharedPreferences → DataStore migration
- Networking & Persistence
- Recipe 16: Retrofit + Coroutines integration.
- Recipe 17: Safe retry with exponential backoff for API calls.
- Recipe 18: Repository pattern: API + Room cache.
- Recipe 19: Room migrations (avoid crashes on schema changes).
- Recipe 20: Mapping API models → domain models with extensions.
- Coroutines & Flow in Android
- Recipe 21: Using viewModelScope.launch correctly.
- Recipe 22: Switching threads with withContext(Dispatchers.IO).
- Recipe 23: Handling cancellation in coroutines.
- Recipe 24: Flow + debounce for search bars.
- Recipe 25: Testing coroutines with runTest + TestDispatcher.
- Jetpack Compose Essentials
- Recipe 26: State hoisting in Compose (lifting state up).
- Recipe 27: Using rememberSaveable to persist across rotations.
- Recipe 28: LazyColumn best practices (keys, avoiding recomposition).
- Recipe 29: Preview parameter providers for test data.
- Recipe 30: Theming with Material 3 in Kotlin.
- Dependency Injection & Architecture
- Recipe 31: ViewModel Assisted Injection with Hilt.
- Recipe 32: Modularizing Android projects (domain/data/ui).
- Recipe 33: Using inline value classes for stronger typing.
- Recipe 34: Creating a sealed error hierarchy (AppException).
- Recipe 35: Clean MVVM pattern in Kotlin (with Repository + UseCases).
- Advanced Kotlin in Android
- Recipe 36: Reducing method count (@JvmField, const val).
- Recipe 37: Avoiding performance pitfalls (lambdas, allocations).
- Recipe 38: Interop with Java: @JvmStatic, @JvmOverloads.
- Recipe 39: SupervisorScope for independent coroutines.
- Recipe 40: WorkManager + CoroutineWorker for resilient background tasks.
- Appendix A: Beginner to Intermediate Recipes
- Using apply, let, also, run scope functions (when to use each).
- Creating companion objects as factories instead of static helpers.
- Using when expression instead of multiple if/else.
- Default values in data classes for cleaner constructors.
- Smart casts with is operator (safe type checks).
- Null coalescing with ?: operator.
- Using lateinit safely (when it’s OK, when it’s not).
- String resource formatting with placeholders (getString(R.string.hello, name)).
- Simple sealed class navigation (before using Jetpack Navigation).
- Handling RecyclerView clicks with lambdas instead of interfaces.
- Using const val for compile-time constants.
- Testing simple functions with JUnit & Kotlin test DSL.
- Creating inline helper extensions (fun View.show() / fun View.hide()).
- Using Pair and Triple effectively (vs. creating a new class).
- Filtering & mapping lists with Kotlin collection operators (filter, map, firstOrNull).
- Kotlin Basics for Android
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