Using Kotlin to build the Lunaconf 2022 App

Use cross-platform frameworks: Work with Flutter, React Native, or Ionic

Use native frameworks: Work with Java or Kotlin

Jetpack Compose: Jetpack-Compose allowed individual team members to write components without someone creating the master screen first. That allowed team members to divide parts of the UI and work independently.

Less code: We loved how little code we had to write to implement features. Those who implemented a RecyclerView with a ViewModel can relate to writing at least 100 lines of boilerplate code for that. With Jetpack Compose-s LazyColumn, it requires only a few lines to create a list of items.

Extension functions: If we need a function that creates String to date, we can create an extension function on java.lang.String to convert a String to a Date object. This was useful to create utility functions on objects.

Flows and Streams: We loved first-class support for Flows and Streams in Kotlin. It was exceptional how easy it was to define data flows from an HTTP request or query an internal SQLite database.

Co-routines: Co-routines support was helpful for us to switch between the UI thread and the IO thread. Android requires the UI thread to be non-blocking. In most cases, we need to perform a network request and, based on the response payload do something on UI. That was easy to do with Kotlin. We need to be able to switch between the UI and IO contexts and be extra careful while doing so. With Java, we need to write a lot more code to switch contexts between UI and IO threads.

Null Safety: Kotlin’s Null Safety is another helpful feature of the language that we loved. The most common use case for causing an NPE in Android apps is when the app goes to the background right before a network request handler draws something to the UI. With Kotlin, it was easy for us to write code that avoided these caveats. That was a massive achievement.

Same problems of component-based UI systems: We inherited all the relevant problems of using component-based UI frameworks/libraries like React/Flutter/Ionic when we decided to use Jetpack-Compose. We struggled with prop drilling issues. React solves the prop-drilling with the Context API, whereas Flutter has the Provider API, but Jetpack compose has nothing yet because it is so new. The only recommended way to solve it is by using a DI engine like HILT.

Experimental API: Since Jetpack-Compose is so new, a lot of the APIs we were using were experimental and subject to change. That didn’t boost our confidence in the code we were writing.

Navigation: Navigation was another problem we faced because Jetpack compose is a new framework. React solved it using the React Router; Flutter has a go_router package; but for Jetpack-Compose we had to write some custom code for maintaining the Navigation back stack.