Rivu Chakraborty

Bengaluru, India

Let's Talk Composing UI

While Developing Apps, following a Reactive Architecture (for example MVI, Mobius, Redux and even MVVM) & Single Source of Truth can get you some big wins including but not limited to, Loose Coupling & Separation of Concerns, Code Testability and easy debugging, unidirectional data, etc. However, unlike Web, where Reactive Architectures are the norm, in Android, we need to opt for Reactive Architecture considering few tradeoffs (time to market, learning curve, etc.), as it’s not natural in Android.

What do I mean by saying Reactive architecture is not natural in Android? Just like web frontends, Android apps revolve around the UI, everything we do in our Android apps has some direct or indirect relation with the UI, and the Android UI framework is imperative itself.
While the Android Platform team kept adding more and more types of Views (such as Constraint Layout, RecyclerView or more recent Motion Layout), they didn’t change the nature of UI framework itself since the beginning of android development. This was majorly due to language and tooling limitations (limited by the technologies of that time).

Google announced official support for Kotlin 2 years back, and now major numbers of professional Android Developers worldwide already adopted Kotlin, which made it easier for Google to go Kotlin first in this IO19. Kotlin comes with many perks, some of them are Functional Programming support, compiler plugin capabilities and most importantly huge support on building DSLs at ease.

What relation does Koltin have with Reactive applications? In this IO19, Google announced Jetpack Compose (https://developer.android.com/jetpack/compose/), a new (still-in-development) next generation, Kotlin based, reactive cum declarative UI toolkit, backed by principals like Single Source of Truth, Unidirectional Data Flow, Functional Programming (especially function composition and effects).

This new UI toolkit would require a radical shift in our thought process about app architectures UI programming. In this talk, we would see how we can create and interact with UI with Jetpack Compose and how different it is from the present Android framework. We will also look into examples of some code patterns and ideas of from a few famous platforms such as Vue.js, React, Flutters, etc., and how these patterns and are adopted in Jetpack Compose.


Rivu Chakraborty

Kotlin Evangelist, Author, Speaker, Community Person, Sr. Android Dev.

Rivu Chakraborty is a Google Certified Android Developer, Caster.io instructor, Sr. Tech Member of Institute of Engineers (India). Having total 7+ years of experience he is presently working as a Sr. Software Engineer (Android) at BYJU'S The Learning App. He has authored multiple Kotlin and Android Development books including Reactive Programming in Kotlin, Functional Kotlin, Hands-On Data Structures and Algorithms with Kotlin and Coroutines for Android Developers.

Rivu considers himself a Kotlin and Android enthusiast cum evangelist, with around 4 years of Kotlin experience. Rivu created the KotlinKolkata User Group and before moving out to Bangalore, he had been the lead organizer for both Kotlin Kolkata User Group and GDG Kolkata.

Along with organizing events, he also speaks at events/conferences, including DroidJam India 2018 (India's premiere Android Conference), and a lot of meetups and DevFests all over India regularly

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