Swift on Android: Full Native App Development Now Possible

Original Article ↗ Hacker News Discussion ↗

What SwifDroid / Swift Stream IDE Enables

  • Lets developers write full native Android apps entirely in Swift, avoiding XML, Java, and Kotlin.
  • Framework handles lifecycle, activities/fragments, and Android/AndroidX/Material widgets; IDE generates a conventional Gradle project usable in Android Studio.
  • Target audience highlighted: Swift-heavy teams wanting Android without switching languages, or iOS‑first products needing “checkbox” Android support.

JNI, Gradle, and Tooling Details

  • Java/Kotlin interop is done via a dedicated jni-kit library plus auto‑generated Java/Kotlin glue (e.g., for Activities).
  • Alternative Swift–Java options like swift-java (with macros/Panama) are mentioned.
  • Gradle is still the underlying build system; SwifDroid wires dependencies automatically so most users don’t touch Gradle directly.
  • Some see Gradle as a nightmare; others argue it’s simpler than iOS/Xcode’s project and dependency management.

Positioning vs Other Cross‑Platform Approaches

  • Explicitly not a cross‑platform UI toolkit: it’s Android‑native UI written in Swift, unlike Flutter, React Native, or Skip/SwiftCrossUI.
  • Compared to Kotlin Multiplatform and Skip: those aim at shared or translated UI; SwifDroid focuses on Android‑only but with full native control from Swift.

Language & Framework Debates (Swift, Kotlin, Dart)

  • Large side discussion comparing Dart/Flutter, Kotlin/KMP, and Swift:
    • Some strongly prefer Kotlin Multiplatform over Flutter; others the opposite.
    • Opinions on Dart range from “best modern app language” to “clunky and aged”; criticisms include JSON serialization and web canvas rendering.
    • Kotlin is praised by some, but others find its syntax and ergonomics “off” compared to Swift.
    • Swift is seen by some as painful post‑Swift 6; others are surprised by that characterization.

Cross‑Platform vs Native: Productivity vs UX

  • Several commenters argue shared language rarely delivers the expected productivity gain; platform APIs, lifecycle, and idioms dominate the learning curve.
  • Others value cross‑platform stacks for synchronized feature rollout and consistent UX across platforms, citing React Native’s fast refresh, deep‑linking, OTA updates, and easy native escape hatches.
  • There’s broad agreement that serious apps often hit abstraction leaks and need platform‑specific code.

Skepticism, Limitations, and Open Questions

  • Concern that Android APIs are mostly Java‑exposed, so Swift layers must go through JNI and will be inherently leaky.
  • Questions raised about C/C++ interop and SwiftPM/Bazel dependency handling are not deeply answered in the thread.
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