# DroidCore

> A 20-module Android developer roadmap for 2026, from OS internals through Jetpack Compose, Kotlin Coroutines, Clean Architecture, Hilt, Room, and Google Play publishing.

DroidCore is a 20-module Android developer roadmap. Each module is a long-form lesson. Publisher: BufferSync. Contact: hello@buffersync.com

## Primary topics

- Android developer roadmap 2026
- Jetpack Compose
- Kotlin Coroutines and Flow
- Android Clean Architecture and MVVM
- Hilt dependency injection
- Room database
- Android activity lifecycle and fragments
- WorkManager
- Retrofit
- Android Gradle plugin
- Google Play publishing

## Modules

- [Android Ecosystem & Architecture](https://droidcore.buffersync.com/docs/01-android-ecosystem-architecture): Learn the foundations of the Android operating system, its software stack, kernel, HAL, and runtime environment.
- [Kotlin Essentials for Android](https://droidcore.buffersync.com/docs/02-kotlin-essentials-for-android): Master Kotlin programming language features essential for Android development including OOP, functional syntax, and coroutines basics.
- [Android Project Structure & Build System](https://droidcore.buffersync.com/docs/03-android-project-structure-build-system): Understand Android project anatomy, module structures, manifest configurations, resource qualifiers, and the Gradle build system.
- [Android app components](https://droidcore.buffersync.com/docs/04-android-app-components): Android app components: Activities, Services, Broadcast Receivers, and Content Providers, and how they fit together.
- [Android activity lifecycle](https://droidcore.buffersync.com/docs/05-activity-lifecycle-deep-dive): Android activity lifecycle states, callbacks, configuration changes, and how to preserve UI state.
- [Android fragments](https://droidcore.buffersync.com/docs/06-fragments-deep-dive): Android fragments versus activities, fragment lifecycle, and navigation with fragments.
- [Jetpack Compose vs XML](https://droidcore.buffersync.com/docs/07-ui-development-xml-jetpack-compose): Jetpack Compose vs XML: View hierarchy, declarative UI, state, recomposition, and when each layout system still wins.
- [Navigation & Intents (Deep Dive)](https://droidcore.buffersync.com/docs/08-navigation-intents-deep-dive): Master app navigation strategies, dynamic navigation graphs, deep linking, and data sharing with Intents.
- [RecyclerView & LazyColumn (Deep Dive)](https://droidcore.buffersync.com/docs/09-recyclerview-lazycolumn-deep-dive): Implement high-performance lists and grids using RecyclerView in XML and LazyColumn/LazyRow in Jetpack Compose.
- [Android clean architecture and MVVM](https://droidcore.buffersync.com/docs/10-android-architecture-mvvm-repository-clean-architecture-solid): Android clean architecture with MVVM, the repository pattern, use cases, layers, and SOLID boundaries.
- [Kotlin Coroutines on Android](https://droidcore.buffersync.com/docs/11-concurrency-coroutines-flow-deep-dive): Kotlin Coroutines on Android: dispatchers, structured concurrency, Flow, and common interview-level failure modes.
- [Hilt dependency injection](https://droidcore.buffersync.com/docs/12-dependency-injection-hilt-dagger-deep-dive): Hilt dependency injection on Android with Kotlin: constructors, modules, and using Hilt in Jetpack Compose.
- [Retrofit on Android](https://droidcore.buffersync.com/docs/13-networking-http-rest-retrofit-okhttp-serialization): Retrofit on Android with OkHttp: REST calls, Kotlin serialization, and a networking layer you can test.
- [Room database on Android](https://droidcore.buffersync.com/docs/14-local-data-persistence-room-sqlite-datastore-offline-first): Room database on Android with Kotlin: entities, DAOs, SQLite under the hood, DataStore, and offline-first design.
- [WorkManager on Android](https://droidcore.buffersync.com/docs/15-background-work-services-workmanager-foreground-services-scheduling): WorkManager on Android: deferred work, foreground services, constraints, and when a Service is still the right tool.
- [Testing (Unit Testing, Instrumentation, UI Testing & Test Architecture)](https://droidcore.buffersync.com/docs/16-testing-unit-testing-instrumentation-ui-testing-test-architecture): Write clean, testable code and implement unit tests, instrumentation tests, UI tests, and test-driven architecture.
- [Performance, Memory & Optimization](https://droidcore.buffersync.com/docs/17-performance-memory-optimization): Optimize Android app performance, profile memory usage, detect leaks, optimize layout rendering, and decrease APK size.
- [Android security and permissions](https://droidcore.buffersync.com/docs/18-android-security-permissions-authentication-encryption-secure-app-design): Android security and permissions: runtime grants, authentication, encryption, and secure storage.
- [Android Gradle plugin](https://droidcore.buffersync.com/docs/19-gradle-build-system-android-project-internals): Android Gradle plugin: versions, build types, product flavors, dependency resolution, and the build cache.
- [Publish an app on Google Play](https://droidcore.buffersync.com/docs/20-publishing-distribution-the-google-play-ecosystem): Publish an app on Google Play: store listing, review, release tracks, staged rollouts, and updates.

## Site

- [DroidCore](https://droidcore.buffersync.com/): Android developer roadmap index
- [Sitemap](https://droidcore.buffersync.com/sitemap-index.xml)
- [Publisher](https://buffersync.com/): BufferSync