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https://github.com/Kotlin/kmp-production-sample

This is an open-source, mobile, cross-platform application built with Kotlin Multiplatform Mobile. It's a simple RSS reader, and you can download it from the App Store and Google Play. It's been designed to demonstrate how KMM can be used in real production projects.
https://github.com/Kotlin/kmp-production-sample

android compose ios jetpack-compose kmm kotlin kotlin-multiplatform kotlin-native multiplatform reactjs sample

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This is an open-source, mobile, cross-platform application built with Kotlin Multiplatform Mobile. It's a simple RSS reader, and you can download it from the App Store and Google Play. It's been designed to demonstrate how KMM can be used in real production projects.

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README 

        
[![official project](http://jb.gg/badges/official.svg)](https://confluence.jetbrains.com/display/ALL/JetBrains+on+GitHub)



# KMM RSS Reader



  



This is an open-source, mobile, cross-platform application built

with [Kotlin Multiplatform Mobile](https://kotlinlang.org/lp/mobile/).



## Compose multiplatform experiment



iOS and Desktop clients were implemented as experimental features and can be viewed [here](https://github.com/Kotlin/kmm-production-sample/tree/compose-app).






## Desktop and Web experiment



Desktop and Web clients were implemented as experimental features and can be viewed [here](https://github.com/Kotlin/kmm-production-sample/tree/c6a0d9182802490d17729ae634fb59268f68a447).






## Project structure



This repository contains a common Kotlin Multiplatform module, a Android project

and an iOS project. The common module is connected with the Android project via the

Gradle multi-project mechanism. For use in iOS applications, the shared module compiles into a

framework that is exposed to the Xcode project via the internal integration Gradle task. This

framework connects to the Xcode project that builds an iOS application.



You can achieve the same structure by creating a project with

the [KMM Plugin project wizard](https://plugins.jetbrains.com/plugin/14936-kotlin-multiplatform-mobile)

or cloning the [basic sample project](https://github.com/Kotlin/kmm-sample/).






## Architecture



Kotlin Multiplatform Mobile is a flexible technology that allows you to share only what you want to

share, from the core layer to UI layers.



This sample demonstrates sharing not only the data and domain layers of the app but also the

application state:






### Shared data and domain layers



There are two types of data sources. The network service is for getting RSS feed updates, while

local storage is for caching the feed, which makes it possible to use the application

offline. [Ktor HTTP Client](https://ktor.io/docs/client.html) is used for making API

requests. [Kotlinx.serialization](https://github.com/Kotlin/kotlinx.serialization) is used to

serialize feed data and store it locally

with [MultiplaformSettings](https://github.com/russhwolf/multiplatform-settings). This logic is

organized in the shared module of the `com.github.jetbrains.rssreader.core` package.



### Shared application state



The Redux pattern is used for managing the application state. The simplified Redux architecture is

implemented in the shared module. The `Store` class dispatches the **actions** that can be produced

either by a user or by some async work, and generates the new state. It stores the actual **state**

and facilitates subscription to state updates via Kotlin's `StateFlow`. To provide additional

information about state updates, the `Store` class also produces **effects** that, for example, can

be used to display this information via alerts. This logic is organized in the shared KMM module of

the `com.github.jetbrains.rssreader.app` package.






### Native UI



The UI layer is fully native and implemented using SwiftUI for iOS, Jetpack Compose for Android,

Compose Multiplatform for Desktop and React.js for web browser.



**On the iOS side,** the `Store` from the KMM library is wrapped into the `ObservableObject` and

implements the state as a `@Published` wrapped property. This publishes changes whenever a

dispatched action produces a new state after being reduced in the shared module. The store is

injected as an `Environment Object` into the root view of the application, and is easily accessible

from anywhere in the application. SwiftUI performs all aspects of diffing on the render pass when

your state changes.



For subscribing to state

updates, [the simple wrapper](https://github.com/Kotlin/kmm-production-sample/blob/master/shared/src/iosMain/kotlin/com/github/jetbrains/rssreader/core/CFlow.kt)

is used. This wrapper allows you to provide a callback that will be called when each new value (the

state in our case) is emitted.



## Multiplatform features used



**✅ Platform-specific API usage.** RSS feeds usually only support the XML format.

The `kotlinx.serialization` library currently doesn't support parsing XML data, but there is no need

to implement your own parser. Instead, platform libraries (`XmlPullParser` for

Android and `NSXMLParser` for iOS) are used. The common `FeedParser` interface

is declared in the `commonMain` source set. Platform implementations are placed in the

corresponding `iOSMain` and `AndroidMain` source sets. They are injected into the

RSSReader class (the KMM module entry point) via the `create` factory method, which is declared in

the [RSSReader class companion object](https://github.com/Kotlin/kmm-production-sample/blob/master/shared/src/androidMain/kotlin/com/github/jetbrains/rssreader/core/RssReader.kt).