Master the Android System Design Interview: Advanced Topics

Split large interfaces into smaller, purpose-specific ones to apply interface segregation. This lets clients depend only on what they use, reducing side effects and changes.

Explore the open closed principle by using a node persistence interface with file and database implementations. Extend with new persistence forms without modifying existing code.

Explore MVC, MVP, and MVVM, their components and data flows, and learn when to apply each pattern in Android apps with a notes demo.

Explore the model-view-viewmodel (mvvm) pattern, where the view reacts to viewmodel state via LiveData or State Flow, enabling separation of concerns and robust, testable UI.

Explore the MVVM pattern in practice with a refactored notes app, detailing model, view, and viewmodel roles, reactive state flow, and how the UI updates via compose.

Explore clean architecture, its goals and strategies, and its components, and learn when to apply or avoid it, review use cases, and examine a practical example.

Implement clean architecture by organizing code into inner entities and use cases, with controllers, gateways, and presenters, while layers like UI and database depend inward according to the dependency rule.

Adopt offline first design by making the local data source the single source of truth in repositories, and synchronize with remote data using pull, push, or hybrid strategies.

Explore the UI and domain layer updates, including the notes UI state (loading, error, content) exposed via state flow, and the viewmodel's load, add, delete, share, and sync use cases.

Explore the view binding library for Android UI layers. It generates binding classes from XML layouts, offers null and type safety, and replaces findViewById, with usage in activities and fragments.

Explore advanced data binding with binding adapters, custom naming, and binding converters; learn two-way binding, inverse binding adapters, and how LiveData, observable ViewModel, and ViewModel integrate with binding and lifecycle.

Demonstrate how the lifecycle API integrates with Jetpack Compose by making the note screen lifecycle aware using the local lifecycle owner, state flow, and lifecycle event and start effects.

Explore how the ViewModel serves as a screen-level stakeholder that handles UI state and events, delegates them to the domain or data layer, and persists UI state across configuration changes.

Learn how the ViewModel's saved state handle preserves UI state across process death using a key-value map, with integration to live data, State flow, and a Jetpack Compose state APIs.

Jetpack data store and Proto Datastore replace SharedPreferences with asynchronous, type-safe APIs, offering transactional reads and safe IO, plus migration paths from SharedPreferences.

Master WorkManager for persistent Android background work, covering immediate, long running, and deferrable tasks, one-time and periodic scheduling, constraints, retries, and work chaining.

Explore the navigation controller, destination types host, dialog, activity, backstack, navigation graph, deep links, typesafe navigation with fragments and Jetpack Compose, and integrations with Dynamic Navigator and navigation UI demo.

Explore the navigation controller as the central navigation API that manages the navigation graph and backstack, establishing a single source of truth across activities, fragments, and views.

Master nested navigation graphs in Jetpack Compose to encapsulate onboarding and login flows, keep the main graph simple, and reuse subgraphs accessed via a single entry point.

Explore how to pass typed arguments to destinations with type-safe navigation, compare fragment-based and compose navigation, and implement safe-args generated APIs with default values.

Compare the service locator pattern with dependency injection, detailing how a locator creates and stores dependencies and how classes request them on demand, noting testing challenges and lack of scoping.

Dagger, the long-standing framework, generates an app graph and injects dependencies at compile time, using annotations, singleton and custom scopes, subcomponents, and supports binds, provides, and field injection.

Compare dependency injection frameworks—tag and tilt versus coin and codeine—covering compile-time vs runtime construction, language compatibility, testing support, ViewModel integration, and community backing.

Explore modularization principles for maintainable multimodal Android apps, focusing on cohesion and coupling, and explain separation by layer, separation by feature, and data, feature, app, core, and test models.

Explore Android app modularization strategies, from layer-based to feature-based and hybrid approaches. Evaluate cohesion, coupling, and granularity to optimize scalability and build times.

Apply modularization to a notes demo app using a layered architecture with data, domain, and UI modules; implement dependency injection with Hilt and Gradle version catalogs for clean architecture.

Explore Android privacy and security foundations, from permissions and location minimization to data handling, privacy UI elements, app hibernation, secure storage, cryptography, and network and authentication safeguards.