Series

Android, Line by Line

5 parts, in order. Start at the top — each one assumes the one before it.

  1. 01 Let's Make WorkManager Work: Constraints, Unique Work, and a Retry That Stops Forty lines that run a job surviving the app being killed. Three decisions inside are worth stealing, and one line is a bug you can ship without noticing — because CancellationException is an Exception. 4 min read
  2. 02 Let's Make SupervisorJob Work: Independent Failure Without Breaking the Tree One child throws and the whole scope dies. SupervisorJob fixes that — but you probably already have one and didn't know, and the way most people reach for it does nothing except break structured concurrency. 4 min read
  3. 03 Let's Make a Callback Suspend: suspendCancellableCoroutine, Line by Line Wrapping a callback API in a suspend function is four lines. The fifth line — invokeOnCancellation — is the one that decides whether cancelling actually stops anything, and it's the one people leave out. 4 min read
  4. 04 Let's Make a KMP Project Build: The Scaffold, Line by Line Fifteen files, no app code, and nothing to run. The first commit of a Kotlin Multiplatform project decides how every module after it gets built — and one line in it prevents a crash that compiles cleanly and passes every test. 4 min read
  5. 05 Let's Make Modifier Work: The Order Is the API Modifier chains read like a list of properties and behave like a pipeline. Swap two calls and you get a different widget — and the version that looks right is sometimes right by accident, which is worse than being wrong. 4 min read