App size is a key metric impacting user acquisition and retention: If the app is too large to download, users may skip installation or cancel the installation during downloading; if the app takes too much storage space after use, users may choose to uninstall. There are also different measurements of…

For an Android application maintained by a large group of developers, build time is one of the most critical developer ergonomic metrics. This is particularly true when we evaluate to adopt new technology. Jetpack Compose is the new exciting modern UI library to build Android applications. Its official documentation already…

Along with the coroutine adoption, StateFlowbecomes an alternative observable data holder for LiveDatasince StateFlowhas almost all the functionalities of LiveDatawithout the main thread confinment. On top of following the best practice of the safer way to collect flows from Android UI, this story covers another common pitfall in detail. Setup I…

Android KTX provides opinionated methods facilitating using Kotlin Coroutines in Android Architecture Components. For instance, Flow<T>.asLiveData() is quite helpful to migrate your apps using LiveData towards coroutine. Make sure to understand their behaviors underneath before using them! This story is a continuation of the previous one. Lesson III: Unfinished coroutines during unit tests When converting from…

Have you ever got frustrated to debug LiveData changes by adding numerous log statements or breakpoints? As the core data structure of Android Architecture Components, LiveData is used widely in many apps to hold observable data. However, its debugging experience could still be a pain point after these many years. Observing LiveData changes at scale …

Android KTX provides opinionated methods, such asFlow<T>.asLiveData(), facilitating using Kotlin Coroutines in Android Architecture Components. Make sure to understand their behaviors underneath before using them! The official documentation on Kotlin coroutines on Android is quitewell-written, while there are numerous article posts covering the basics. In this story, we will focus…

If generic types are exposed in Kotlin API, consider @JvmSuppressWildcards so that your Java consumer can compile successfully. Kotlin generics are different from (in my opinion, smarter than) Java generics. Kotlin generics has declaration-site variance and type projections, which are officially documented here. Generics is a gigantic topic itself. …

A simple trick to write an email report for your readers Recently my team wrote an email report to the leadership team on the executive summary of Android Gradle Plugin upgrades. Below is the initial version of the reports in the exec summary section: - We have migrated to Android…

This article is an English version of the blog. All credits belong to oboenikui. MockK is a mocking library written in Kotlin and for Kotlin. In addition to the traditional functionality provided by JVM based mocking libraries, Kotlin’s language feature significantly improves MockK’s usability. However, aside from MockK, have you…