Software Development

Lifecycle ViewModel 2.11.0-alpha02 introduces rememberViewModelStoreOwner, an API to scope ViewModelStore directly within the Compose hierarchy. Why It Matters Until now, ViewModelStore scoping was tied to navigation destinations, activities or fragments. There was no clean way to scope a ViewModel to an arbitrary part of your UI (such as a Pager page, a LazyList item, or a custom layout) without building your own ViewModelStoreOwner from scratch. These new APIs close that gap:...

NavigationEvent is a Kotlin Multiplatform library for handling system gestures - back and forward - on all platforms. It works on Android, iOS and Desktop with Web support coming next. Android rely on OnBackPressedDispatcher from androidx.activity. It handles back presses, and that was enough. But once you target more than Android, you also need forward navigation - like on the web. That’s why NavigationEvent exists: one event system that works everywhere....

I’ve been using the IDEA Vim plugin in Android Studio for a while. I only ever learned the basics with Practical Vim, but that’s been enough. The nice part is how the same muscle memory works everywhere: I can edit the same way in Android Studio, VS Code, iTerm, or Obsidian. Most editor-specific shortcuts I used to know are gone, and I don’t miss them. IDEA Vim config Here’s my ....

Lifecycle 2.9.0-alpha01 introduced ViewModelScenario, a helper that simplifies unit testing for ViewModels. Why It Matters You can test a ViewModel by simply creating an instance using its constructor in your test code. However, this approach has limitations — there is no straightforward way to: Trigger ViewModelStore.clear()/ViewModel.onCleared(). Simulate a save and restore instance state. With ViewModelScenario, these are now easy to test, helping you catch errors related to ViewModel clean-up and saved state....

To me, using functions as properties in the primary constructor of a data class is a code smell. Here’s why: Data classes represent data. Data is a value. Data is never executed. Functions are not data. They produce values when executed. Note: By the book, a function returns a value, while a procedure executes commands. In both cases, neither is data. Why It Matters Kotlin generates key methods for data classes based on the properties in the primary constructor, such as:...

Sharing tests across Kotlin Multiplatform (KMP) projects can be tricky when dealing with platform-specific APIs like Android’s Bundle. commonTest on Android relies on the androidTest source set, which uses an empty android.jar, leading to test failures. The Solution The ideal solution is to avoid platform-specific APIs in commonTest. If that’s not an option, you can use Robolectric in your commonTest source set to access functional Android classes. This approach: Allows testing of platform-specific code in commonTest....

Heads-up: this article assumes familiarity with Kotlin’s extension functions and expect and actual declarations in Kotlin Multiplatform (KMP). My work has recently focused on “commonizing”1 APIs, and I came across KT-70012, which I believe merits attention. In Kotlin JVM development, the EXTENSION_SHADOWED_BY_MEMBER warning indicates that an extension function is redundant, as it will always be overshadowed by a member function with the same name when invoked. However, in KMP, this behaviour can be useful, as shadowing may occur on some platforms but not all....

Disclaimer: It has been brought to my attention the title can be seen as a click bait. That wasn’t my intention and I’m sorry. I wanted to reference the Fallout game series and the No Mutants Allowed community. Testable code plays a crucial role in app development. When we neglect designing code for testability, we often resort to using a mock library (such as Mockito Kotlin, also know as “auto-mockers”) as a mean to achieve test coverage....

Android has made significant progress in becoming a DI-Friendly Framework. Throughout the years, new APIs like AppComponentFactory and FragmentFactory have been introduced, allowing apps to incorporate their own custom constructors and facilitating the development of testable code. The purpose of this article is to highlight some of the Android APIs that are utilised behind the scenes. By exploring these APIs, developers can gain a better understanding of the underlying mechanisms employed by popular libraries (such as Dagger Hilt and Koin Android)....

A few weeks ago, I had to create an extension function - a usual task for any Kotlin developer. But there were a few limitations: The receiver was a common type, polluted with too many methods. The extension function was only relevant to my feature package. Creating a Gradle module was out of scope. Introducing a new type to hold the function felt like too much. Kotlin doesn’t support package-private, yet....