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Using annotations to improve iOS APIs on Kotlin Multiplatform

Kotlin 1.8 has introduced new annotations to improve the interoperability of Kotlin with Objective-C and Swift: @ObjCName: allows to customize the name that will be used in Swift or Objective-C @HiddenFromObjC: allows hiding a Kotlin declaration from Objective-C (and Swift). @ShouldRefineInSwift: it marks a Kotlin declaration as swift_private in the Objective-C API, allowing to replace it with a wrapper written in Swift. You can see the release announcement for more details about the interoperability improvements introduced with Kotlin 1....

Introducing FeedFlow, a minimalistic and opinionated RSS Reader

After months of work, I can finally announce the release of FeedFlow, a minimalistic and opinionated RSS Reader that I’ve built for myself and that’s now available on Android, iOS, and macOS. Motivation I’ve started (again) to stay up to date by building my own feed instead of relying on feeds ordered and decided by someone else. But I wasn’t completely satisfied with the readers already out there (“I can build a better one"™️)....

Migrating to Jetpack Compose: a step by step journey

Some time ago, I decided to migrate Secure QR Reader to Jetpack Compose (in the rest of the article, I will call it Compose, for brevity). QR Reader Secure is a simple QR Reader that I developed some years ago after a failed search for a simple and secure reader for my parents that doesn’t require sneaky, strange, and useless permissions. The app was basic and fully working with the old View system, but I wanted to move to Compose to experience the entire migration process....

Organize your Views: SwiftUI edition

One of the pros of SwiftUI, and generally of declarative UI frameworks, is the capability of defining the UI with the same programming language the application uses. With SwiftUI, it is not necessary anymore to bridge the UI definitions from somewhere else, resulting in a decrease of context switching between two different environments (Storyboards and Swift code, for example) But “with great power comes great responsibility”, and a codebase can quickly become a nightmare without some structure and organization....

Organize your Views: Jetpack Compose edition

One of the pros of Jetpack Compose (in the rest of the article, I will just call it Compose, for brevity), and generally of declarative UI frameworks, is the capability of defining the UI with the same programming language the rest of the application uses. With Compose, it is not necessary anymore to bridge the UI definitions from XML (e.g. with the [in]famous findViewById), resulting in less context switching between two different environments (XML and Kotlin code)....

How to create a parameterized base test class in Kotlin

One exciting feature of JUnit 4 (and 5 as well, but this post will be focused on JUnit 4) is the possibility of running the same test with different input arguments. That is made possible by a custom test runner called Parameterized, which will inject the provided arguments in the constructor of the test class. Instead, the different arguments must be defined in the companion object of the test class....

Improving shared architecture for a Kotlin Multiplatform, Jetpack Compose and SwiftUI app

A couple of years ago I started working on a pet project to manage personal finances, named MoneyFlow. This project soon became a personal playground for a Kotlin Multiplatform mobile app and in a previous article, I journaled all the steps that lead me to a satisfying (at least for that time) shared app architecture. Choosing the right architecture for a [new] Kotlin Multiplatform, Jetpack Compose and SwiftUI app...

Moving from mobile to backend development with Ktor

SERIES: Building a backend with Ktor Part 1: Structuring a Ktor project Part 2: How to persist Ktor logs Part 3: How to use an in-memory database for testing on Ktor Part 4: How to handle database migrations with Liquibase on Ktor Part 5: Generate API documentation from Swagger on Ktor Part 6: How to schedule jobs with Quartz on Ktor Part 7: Moving from mobile to backend development with Ktor This article is the final instance of the series of posts dedicated to Ktor where I cover all the topics that made me struggle during development and that were not easy to achieve out of the box....

How to schedule jobs with Quartz on Ktor

SERIES: Building a backend with Ktor Part 1: Structuring a Ktor project Part 2: How to persist Ktor logs Part 3: How to use an in-memory database for testing on Ktor Part 4: How to handle database migrations with Liquibase on Ktor Part 5: Generate API documentation from Swagger on Ktor Part 6: How to schedule jobs with Quartz on Ktor Part 7: Moving from mobile to backend development with Ktor Sometimes, on a backend project, there is the need to run one or more tasks periodically, like for system administration, maintenance, backup, syncing content in the background, etc....

Generate API documentation from Swagger on Ktor

SERIES: Building a backend with Ktor Part 1: Structuring a Ktor project Part 2: How to persist Ktor logs Part 3: How to use an in-memory database for testing on Ktor Part 4: How to handle database migrations with Liquibase on Ktor Part 5: Generate API documentation from Swagger on Ktor Part 6: How to schedule jobs with Quartz on Ktor Part 7: Moving from mobile to backend development with Ktor When a backend project exposes some APIs, there should also be a place where the clients of those APIs can see and understand what can be consumed....

How to handle database migrations with Liquibase on Ktor

SERIES: Building a backend with Ktor Part 1: Structuring a Ktor project Part 2: How to persist Ktor logs Part 3: How to use an in-memory database for testing on Ktor Part 4: How to handle database migrations with Liquibase on Ktor Part 5 Generate API documentation from Swagger on Ktor Part 6: How to schedule jobs with Quartz on Ktor Part 7: Moving from mobile to backend development with Ktor Databases are an important and critical part of backend infrastructures....

How to fix the "Unable to locate a Java Runtime" error on Xcode with Kotlin Multiplatform

A couple of days ago I opened my Kotlin Multiplatform pet project MoneyFlow on a different machine than usual. When I tried to run the app on the iOS simulator on Xcode, the build failed with a very strange error: “The operation couldn’t be completed. Unable to locate a Java Runtime”. This was a very strange issue because the JDK is installed and everything is working on the command line and Android Studio/IntelliJ....