Remember the last time you were trying to validate an email address? Or you struggled to create a RegEx to find all the matches for a specified pattern in a string? Chances are high that you ended up just copying a RegEx (that you didn’t understand) from the internet. iOS 16 tries to solve this by introducing a new intuitive way how to write and understand regular expressions with the RegexBuilder. Introduction Regular expressions (regexes) haven’t changed much since their introduction in the 50s and native language support for them has been similarly stagnant in its design. As useful as they ..read more

Probably every mobile developer knows these small but annoying bugs: The general toolbar of the app is restyled, and it looks good on 29 out of the total 30 screens but on one of the screens some UI elements moved unnoticed onto the wrong positions. Something like this is easily overseen in manual testing since the QA would need to test the change on every device. Wouldn’t it be cool to have a convenient and easy way to find such regressions quickly and keep track of UI changes? Snapshot testing solves this by automatically comparing the previous and the new build. What is Snapshot testing ..read more

With async/await Apple introduced yet again another way of making asynchronous calls in Swift. There are now three different ways of making asynchronous calls: Completion handlers, Combine and async/await – If you also take community solutions like RxSwift or ReactiveSwift into account there are even more. What are we actually supposed to use now? Is there an obvious winner or is it once again in the detail? Let’s find out! The Approaches to Asynchronous Swift code Let’s first recap the three different approaches to how asynchronous code can be written in Swift. In this article we will cover ..read more

Are you aware that every Dart method can throw an exception at any time? Many Flutter developers understand exceptions the wrong way because exceptions in Dart are different compared to many other languages. Not only can an exception cause an ugly error, but it can also break the users’ flow. This often results in users disliking your Flutter app or creating bad reviews in the app stores. But don’t worry because we’ve got you covered. We take a deep dive into when and how exceptions should be handled in Dart and Flutter, and also how to tell the user that something went wrong. This will make ..read more

Have you ever wondered why we have to use Kotlin for Android and Swift for iOS development? We asked ourselves the same question and came quickly to the conclusion that there might be a way to solve this. Follow us on an adventure where we learn why and how we store source code and how the Abstract Syntax Tree could help to make App development language independent. What if we lived in an imaginary world where you and your colleague could both look at the same source code file seeing Swift code while you look at your preferred language – Kotlin? What if we stored source code in a language-in ..read more

Have you heard of Wordle? Chances are you have as it really went viral on Twitter the past few weeks. It’s a simple game that’s truly addictive. We were also “infected” with the Wordle hype, played a lot, and realized that it’s the perfect project for getting started with SwiftUI! So in less than two days, we built the game from scratch in SwiftUI. In this article, we’re going to show you how. You’ll learn about bindings, property wrappers, and observed objects in a practical and fun way. Enjoy! What’s Wordle? Wordle is a play on words – in a double sense: It’s a game where you have to guess ..read more

With the release of Kotlin 1.5.0, value classes (formerly known as inline classes) are finally stable and were released from their @OptIn annotations. Many were hyped about the release, but it also created a lot of confusion as we now have three very similar tools in Kotlin: Typealises, data classes, and value classes. So which one shall we use now? Can we drop our type aliases and data classes altogether and replace them all with value classes? That’s what we’re going to explore in this article. The Problem Classes in Kotlin solve two problems: They convey meaning through their name and mak ..read more

Combine is the new cool kid in town when it comes to reactive programming with Swift, so many developers in the community want to switch from RxSwift to Combine. Both frameworks are very similar, but the devil’s in the details and if you want to make the transition, it really helps to have a clear mapping from all the RxSwift operators, types, and functions to their Combine equivalents. Well, here it is! If you’re just here for the mapping, you can skip the deep talk and scroll down to the tables. Otherwise, read on to get all the tips and tricks you need for a smooth transition… Reactive pr ..read more

Mixins are a super-powerful feature in Dart and if you’re developing apps with Flutter, you should use them more often! In this article, we’ll show you why – and how. What’s a Mixin? Mixins are awesome because they solve a basic problem that comes with inheritance. They are an elegant way to reuse code from different classes that don’t quite fit into the same class hierarchy. In object-oriented programming languages, A mixin is a class whose methods and properties can be used by other classes – without subclassing. It’s a reusable chunk of code that can be “plugged in” to any class th ..read more

Sealed interfaces were just introduced in Kotlin 1.5 and are a very powerful new feature. But with great power comes great responsibility, so we need to learn when to use and when to not use this newly achieved power. In order to understand sealed interfaces and their use cases, let’s accompany our cute little QuickBirdTM on a journey! Why Sealed? Product Types Our QuickBird is one of those who like to brag about all the places they’ve been to in the world. So let’s provide him with the API onJourneyFinished where he’ll get a certificate as a reward if the journey was successful. Otherwise ..read more