Daily Wisdom – A Minimal Quote App Built with Jetpack Compose

In the ever-evolving landscape of Android development, modernizing applications with the latest architectural components and UI toolkits is paramount for delivering high-performance, scalable, and maintainable software. We present a comprehensive technical deep-dive into Daily Wisdom, a minimal quote application designed to provide users with a daily dose of inspiration. This project leverages the robust capabilities of Jetpack Compose for a declarative UI, MVVM (Model-View-ViewModel) for separation of concerns, Clean Architecture for scalability, Hilt for dependency injection, and WorkManager for reliable daily notifications. As developers committed to code excellence, we detail the intricacies of building this application, offering insights that can help fellow engineers elevate their Android projects.

The Philosophy Behind Daily Wisdom: Simplicity Meets Functionality

The core concept of Daily Wisdom is straightforward: display a single, curated quote every day. However, in software engineering, simplicity is often the hardest to achieve. We designed this application with a “less is more” philosophy, focusing on a distraction-free user interface that prioritizes the content. The challenge lies not just in displaying text, but in creating an experience that feels personal and timely.

User Experience and Interface Design

The user interface is built entirely with Jetpack Compose, Google’s modern toolkit for building native UI. Unlike the traditional View system, Compose allows us to describe the UI state declaratively. This significantly reduces boilerplate code and makes the UI logic easier to read and debug. We focused on a clean, minimalistic aesthetic. The color palette is subdued to avoid eye strain, and typography is chosen for maximum readability. The navigation is intuitive, allowing users to seamlessly transition between the daily quote, their saved favorites, and the settings menu.

The Role of Daily Notifications

To ensure the app remains engaging, we implemented a daily notification system. The goal is to nudge the user gently at a specific time each day, turning the app into a daily ritual rather than a one-time utility. This feature requires careful handling of background tasks and system resources, which we managed using Android’s robust background processing frameworks.

Technical Architecture: Adopting Clean Architecture and MVVM

To ensure the longevity and testability of Daily Wisdom, we adhered to Clean Architecture principles combined with the MVVM pattern. This architectural choice separates the application into distinct layers, each with a specific responsibility.

The Presentation Layer

The presentation layer comprises the UI and the ViewModels. In Daily Wisdom, this layer is written entirely in Kotlin using Jetpack Compose. The ViewModels expose state flows that the UI observes. This unidirectional data flow ensures that the UI always reflects the current state of the application. For example, when a user favorites a quote, the ViewModel updates the state, and Compose automatically recomposes the relevant UI components to reflect the change.

The Domain Layer

The Domain layer acts as the bridge between the presentation and data layers. It contains the business logic and entity definitions (such as the Quote data class). This layer is pure Kotlin, meaning it has no dependencies on Android-specific libraries or the framework. This separation is crucial for unit testing, as we can test the business logic without needing to mock Android components.

The Data Layer

The Data layer is responsible for fetching and storing data. In Daily Wisdom, this involves two primary sources: a remote API (or a local asset file containing quotes) for retrieving new quotes and a local database for storing user favorites. We use a repository pattern to abstract these data sources. The repository decides whether to fetch data from the network or return cached data, ensuring a smooth user experience even in offline scenarios.

Leveraging Jetpack Compose for a Declarative UI

Jetpack Compose is the cornerstone of the Daily Wisdom UI. It fundamentally changes how we think about building Android interfaces.

State Management in Compose

Managing state effectively is critical in Compose. We utilize State and Flow to handle UI state. When the data changes, Compose automatically updates the UI. For instance, the “Favorites” screen observes a list of favorite quotes from the ViewModel. When a new quote is added to the database, the flow emits the updated list, and Compose recomposes the screen to show the new item. This reactive approach eliminates the need for manual UI updates and reduces the likelihood of state inconsistency bugs.

Custom Layouts and Theming

We implemented a custom theme using MaterialTheme to define colors, typography, and shapes. This ensures consistency across the app. Furthermore, we utilized Compose’s layout system to create responsive designs that adapt to various screen sizes and orientations. Whether the user is on a compact phone or a large tablet, the layout adjusts gracefully. We also implemented custom animations for navigation transitions, adding a layer of polish that enhances the perceived quality of the application.

Dependency Injection with Hilt

Managing dependencies manually in a growing application becomes cumbersome and error-prone. We integrated Hilt to handle dependency injection.

Simplifying Dependency Management

Hilt is built on top of Dagger and provides a standard way to incorporate Dagger into Android applications. We define modules for providing instances of ViewModels, Repositories, and Database instances. Hilt automatically generates the dependency graph and makes it available to the classes that need them. For example, the QuoteViewModel is injected with the QuoteRepository without the need for manual instantiation or factory patterns.

Scoping and Lifecycle

Hilt allows us to manage the lifecycle of objects efficiently. By using scopes like @ActivityScoped or @ViewModelScoped, we ensure that objects are created when needed and destroyed when the lifecycle ends, preventing memory leaks. This is particularly important for the database connection and the WorkManager initialization, ensuring resources are released appropriately.

Implementing Background Tasks with WorkManager

The daily notification feature is a critical component of Daily Wisdom. To implement this reliably, we utilized WorkManager.

Reliable Scheduled Execution

WorkManager is the recommended solution for deferrable background work that needs to run even if the app is closed or the device restarts. We created a DailyNotificationWorker class that extends CoroutineWorker. This worker is responsible for fetching the quote of the day and triggering the notification.

Constraint-Based Execution

We configured the work request with constraints to optimize battery life and user experience. For example, we ensured that the notification only triggers when the device is idle or connected to power, if necessary. The work is scheduled using a PeriodicWorkRequest with a 24-hour interval. We also implemented logic to handle timezone changes, ensuring the user receives their notification at the correct local time regardless of where they travel.

Data Persistence and Room Database

To save favorites and persist user preferences, we integrated the Room persistence library.

Entity and Data Access Objects (DAO)

We defined a QuoteEntity to represent the structure of a favorite quote in the database. The DAO interface contains methods for inserting, deleting, and querying quotes. Room validates these SQL queries at compile time, reducing the risk of runtime errors.

Flow Integration

A key feature of Room is its native support for Flow. We expose the list of favorite quotes as a Flow<List<Quote>>. This allows the UI to subscribe to the database and receive real-time updates whenever the data changes. This reactive pattern is the glue that holds the MVVM architecture together, ensuring the UI is always in sync with the underlying data.

Handling the Quote Logic

The logic for selecting the “quote of the day” requires a deterministic algorithm. We cannot simply pick a random quote every day, as the user should see the same quote throughout the day if they reopen the app.

Deterministic Selection Algorithm

We implemented an algorithm that uses the current date as a seed to select a quote from the list. By using the date, we ensure that the selection is consistent for that specific day. The algorithm hashes the date and applies a modulo operation against the total number of quotes to find the index. This ensures that every user sees the same quote on the same day, but the quote changes automatically when the date rolls over.

Handling Edge Cases

We also handled edge cases, such as what happens when the user has already favorited the quote of the day. The UI state checks the local database to display the correct “heart” icon state (filled or outlined). This requires a quick lookup in the DAO, which is efficiently handled via a coroutine to avoid blocking the main thread.

Testing Strategy: Ensuring Code Reliability

A high-quality application requires rigorous testing. We adopted a multi-layered testing approach for Daily Wisdom.

Unit Testing

We wrote unit tests for the Domain and Data layers using JUnit and Mockito. The ViewModel tests verify that the state flows emit the correct values given certain inputs. The Repository tests verify that data is correctly fetched from the appropriate source (remote or local). Since the Domain layer is pure Kotlin, it is easily testable without an Android emulator.

Instrumentation Testing

For the UI, we utilized Espresso or Compose testing libraries to verify that user interactions result in the expected UI changes. For example, we simulate a click on the “Favorite” button and assert that the icon changes state and the item appears in the Favorites list. This ensures that the integration between the View, ViewModel, and Model layers functions as intended.

Optimizing Performance with Jetpack Compose

While Jetpack Compose is efficient by default, optimization is still required for a smooth user experience.

Managing Recomposition

We carefully designed our Composable functions to minimize recomposition. We utilized the remember keyword to retain state across recompositions and derivedStateOf to compute derived values only when dependencies change. We also avoided passing lambdas as parameters if they cause unnecessary recompositions, preferring @Stable interfaces or callback hoisting where appropriate.

Lazy Loading for Favorites

The Favorites screen can potentially grow large. To handle this, we utilized LazyColumn in Compose. This component only composes items that are currently visible on the screen, ensuring that scrolling remains buttery smooth even with hundreds of saved quotes. We also implemented diffing logic so that Compose only recomposes the items that have changed, rather than the entire list.

Accessibility and Internationalization

An app is only truly successful if it is usable by everyone. We incorporated accessibility best practices into Daily Wisdom.

Content Descriptions and Contrast

Every interactive element has a meaningful content description for screen readers like TalkBack. We verified that the text and background colors meet WCAG (Web Content Accessibility Guidelines) contrast ratios to ensure readability for users with visual impairments. Font sizes are also scaled appropriately based on system settings.

Dynamic Colors and Layouts

The app respects the system’s dark mode setting. We defined our color palette in Color.kt and Theme.kt to switch automatically between light and dark themes. This reduces eye strain in low-light conditions and aligns with modern Android design standards.

Future Roadmap and Scalability

While Daily Wisdom is currently a minimal application, its architecture allows for significant scalability.

Potential Feature Additions

We plan to introduce several features in future iterations:

• User-Submitted Quotes: Allowing users to submit their own quotes, which could be vetted and added to the database.
• Cloud Sync: Integrating Firebase or a custom backend to sync favorites across multiple devices.
• Widget Support: Adding a home screen widget to display the quote without opening the app.

Architectural Scalability

Because we used Clean Architecture, adding these features is straightforward. For cloud sync, we would simply add a new data source (e.g., CloudDataSource) and update the Repository to sync data between local and remote sources. The Domain and Presentation layers would remain largely unchanged, proving the robustness of our architectural choices.

Conclusion: The Value of Modern Android Development

Building Daily Wisdom with Jetpack Compose, Hilt, and WorkManager demonstrates the power of the modern Android ecosystem. We created a performant, maintainable, and user-friendly application by adhering to best practices and architectural guidelines. The separation of concerns provided by Clean Architecture ensures that the codebase is easy to understand and extend.

For fellow developers looking to build similar applications, we highly recommend adopting this stack. The learning curve is steep, but the benefits in terms of code quality and developer productivity are immense. We invite you to explore the source code, provide feedback, and contribute to the project. Together, we can build Android applications that not only function well but also stand the test of time.

Deep Dive: The Role of Kotlin Coroutines

Kotlin Coroutines are the backbone of our asynchronous operations. From database access to network calls, coroutines allow us to write non-blocking code in a sequential, readable style.

Structured Concurrency

We leveraged structured concurrency to ensure that coroutines are properly managed within the scope of the ViewModel. When the ViewModel is cleared, all active coroutines are cancelled automatically, preventing memory leaks and unnecessary background processing. This is critical for the daily notification logic, where an uncancelled coroutine could drain battery life.

Flow and StateFlow

We utilized StateFlow to represent the UI state. StateFlow is a hot flow that always retains the current value and replays it to new collectors. This makes it ideal for representing state in a ViewModel, as the UI will immediately receive the latest state upon subscribing. We combined this with SharedFlow for one-time events, such as showing a Snackbar message or navigating to a specific screen.

Detailed Implementation of Daily Notifications

The daily notification system is a standout feature that requires precise implementation.

Setting up WorkManager

We initialized WorkManager in the Application class. The DailyNotificationWorker is enqueued with a PeriodicWorkRequest. The interval is set to 1 day, but we also allow a flex interval so the system can optimize for battery usage. The worker runs in the background, independent of the app’s lifecycle.

Building the Notification

Inside the worker, we fetch the quote of the day using the repository. We then construct a NotificationCompat object. We set the content title to “Daily Wisdom,” the content text to the quote, and an intent that opens the app when the user taps the notification. We also added a “Mark as Read” action that dismisses the notification without opening the app, giving users control over their interaction.

Handling Doze Mode

Android’s Doze mode restricts background activity to save battery. WorkManager handles this gracefully by batching jobs during maintenance windows. However, we configured the work to be NetworkType.CONNECTED if we plan to fetch quotes from an API, ensuring the data is fresh before displaying it. For local quotes, we rely on the deterministic algorithm to select the quote immediately.

UI Components and Compose Primitives

The UI of Daily Wisdom is built using Compose primitives, ensuring high performance and native feel.

Typography and Readability

We used Typography classes to define heading and body text styles. For the main quote display, we increased the font size and line height to improve readability. We also experimented with custom fonts to give the app a unique identity while maintaining clarity.

Interactive Elements

Buttons and icons are built using Icon and Button composables. We added ripple effects to provide visual feedback on touch. For the “Favorite” action, we used a toggleable heart icon that animates when clicked. This micro-interaction makes the app feel responsive and delightful to use.

Modularity and Code Organization

A clean project structure is vital for team collaboration and maintenance. We organized the codebase into packages based on features rather than layers.

Feature Modules

We have a core module containing shared utilities and base classes. Then, we have feature-specific modules like quote, favorites, and settings. Each feature module contains its own ViewModels, UI, and data sources (if specific to that feature). This modular approach allows us to compile only the necessary parts of the app and makes it easier to convert the app into dynamic feature modules in the future.

Dependency Graph

Hilt manages the dependency graph across these modules. We use @InstallIn annotations to specify where dependencies should be available. For example, database-related dependencies are installed in a Singleton component to ensure a single instance across the entire app.

Testing the User Flow

To ensure a seamless user experience, we rigorously tested the end-to-end flow of the application.

The “Quote of the Day” Flow

1. App Launch: We verify that the app launches quickly and displays the correct quote for the day.
2. Favorites: We test adding and removing quotes from favorites. We ensure the state persists after closing and reopening the app.
3. Notifications: We simulate the daily trigger to ensure the notification appears with the correct content. We also test tapping the notification to verify it opens the correct quote in the app.

Edge Case Handling

We tested scenarios such as:

• Empty Database: What happens if the quote database is empty? We implemented a fallback string to prevent crashes.
• Permission Denial: If the user denies notification permission, the app should still function correctly; it just won’t send alerts.
• Screen Rotation: Compose handles configuration changes naturally, but we verified that no state is lost during rotation.

Optimization for Low-End Devices

While the app is lightweight, we ensured it runs smoothly on lower-spec devices.

Memory Management

We avoided loading large bitmaps or heavy resources. Since the app is text-based, the memory footprint is minimal. However, we still optimized the database queries to run on background threads and used pagination if the list of quotes grows large.

Battery Efficiency

The combination of Jetpack Compose (which uses efficient rendering) and WorkManager (which batches background tasks) ensures the app is battery-friendly. We avoided polling the network or keeping sensors active, adhering to Android’s best practices for resource management.

Leveraging the Android Jetpack Libraries

Daily Wisdom is a testament to the power of the Android Jetpack suite.

Navigation Component

We used the Navigation component integrated with Jetpack Compose (NavHost and NavController). This simplifies navigation logic, handling back stack management automatically. We defined a single source of truth for navigation routes, making it easy to add new screens in the future.

Lifecycle Awareness

The ViewModels are lifecycle-aware, ensuring that data loading occurs only when the UI is active. We observed lifecycle owners within Compose to pause updates when the app is in the background, saving system resources.

Conclusion: Building for the Future

Daily Wisdom is more than just a quote app; it is a blueprint for modern Android development. By combining Jetpack Compose, MVVM, Clean Architecture, Hilt, and **WorkManager