Boruto compose app with CLEAN architecture
Jetpack Compose is Android’s modern toolkit for building native UI. It simplifies and accelerates UI development on Android. Quickly bring your app to life with less code, powerful tools, and intuitive Kotlin APIs.
The Navigation component provides support for Jetpack Compose applications. You can navigate between composables while taking advantage of the Navigation component’s infrastructure and features.
State in an app is any value that can change over time. This is a very broad definition and encompasses everything from a Room database to a variable on a class.
All Android apps display state to the user. A few examples of state in Android apps:
- A Snackbar that shows when a network connection can't be established.
- A blog post and associated comments.
- Ripple animations on buttons that play when a user clicks them.
- Stickers that a user can draw on top of an image.
StateFlow and SharedFlow are Flow APIs that enable flows to optimally emit state updates and emit values to multiple consumers.
StateFlow is a state-holder observable flow that emits the current and new state updates to its collectors.
The current state value can also be read through its value property. To update state and send it to the flow,
assign a new value to the value property of the MutableStateFlow class.
In Android, StateFlow is a great fit for classes that need to maintain an observable mutable state.
To convert any flow to a StateFlow, use the stateIn intermediate operator.
StateFlow and LiveData have similarities. Both are observable data holder classes, and both follow a similar pattern when used in your app architecture.
Note, however, that StateFlow and LiveData do behave differently:
- StateFlow requires an initial state to be passed in to the constructor, while LiveData does not.
- LiveData.observe() automatically unregisters the consumer when the view goes to the STOPPED state, whereas collecting from a StateFlow or any other flow does not stop collecting automatically. To achieve the same behavior,you need to collect the flow from a Lifecycle.repeatOnLifecycle block.
The shareIn function returns a SharedFlow, a hot flow that emits values to all consumers that collect from it.
A SharedFlow is a highly-configurable generalization of StateFlow.
A collection of extension libraries for Jetpack Compose
A library that provides utilities for building paginated layouts in Jetpack Compose, similar to Android's ViewPager.
The Paging library helps you load and display pages of data from a larger dataset from local storage or over network. This approach allows your app to use both network bandwidth and system resources more efficiently. The components of the Paging library are designed to fit into the recommended Android app architecture, integrate cleanly with other Jetpack components, and provide first-class Kotlin support.
The Paging library integrates directly into the recommended Android app architecture. The library's components operate in three layers of your app:
- The repository layer
- The ViewModel layer
- The UI layer
The primary Paging library component in the repository layer is PagingSource. Each PagingSource object defines a source of data and how to retrieve data from that source. A PagingSource object can load data from any single source, including network sources and local databases.
Another Paging library component that you might use is RemoteMediator. A RemoteMediator object handles paging from a layered data source, such as a network data source with a local database cache.
The Pager component provides a public API for constructing instances of PagingData that are exposed in reactive streams, based on a PagingSource object and a PagingConfig configuration object.
The component that connects the ViewModel layer to the UI is PagingData. A PagingData object is a container for a snapshot of paginated data. It queries a PagingSource object and stores the result.
The primary Paging library component in the UI layer is PagingDataAdapter, a RecyclerView adapter that handles paginated data (collectAsLazyPagingItems() for compose).
Alternatively, you can use the included AsyncPagingDataDiffer component to build your own custom adapter.
The Room persistence library provides an abstraction layer over SQLite to allow for more robust database access while harnessing the full power of SQLite.
Referencing complex data using Room
Dependency injection (DI) is a technique widely used in programming and well suited to Android development. By following the principles of DI, you lay the groundwork for good app architecture.
Implementing dependency injection provides you with the following advantages:
- Reusability of code
- Ease of refactoring
- Ease of testing
Hilt is a dependency injection library for Android that reduces the boilerplate of doing manual dependency injection in your project. Hilt provides a standard way to use DI in your application by providing containers for every Android class in your project and managing their lifecycles automatically. Hilt is built on top of the popular DI library Dagger to benefit from the compile-time correctness, runtime performance, scalability, and Android Studio support that Dagger provides
Use Hilt with other Jetpack libraries
Jetpack DataStore is a data storage solution that allows you to store key-value pairs or typed objects with protocol buffers. DataStore uses Kotlin coroutines and Flow to store data asynchronously, consistently, and transactionally.
A type-safe HTTP client for Android and Java
In Retrofit you configure which converter is used for the data serialization. Typically to serialize and deserialize objects to and from JSON you use an open-source Java library — Gson. Also if you need, you can add custom converters to Retrofit to process XML or other protocols.
For making HTTP requests Retrofit uses the OkHttp library. OkHttp is a pure HTTP/SPDY client responsible for any low-level network operations, caching, requests and responses manipulation. In contrast, Retrofit is a high-level REST abstraction build on top of OkHttp. Retrofit is strongly coupled with OkHttp and makes intensive use of it.
How to handle RESTful web Services using Retrofit, OkHttp, Gson, Glide and Coroutines