Add 6.3 SDK snapshots and more info, plus some review tweaks asked for

Author: finagolfin

_posts/2025-11-21-exploring-the-swift-sdk-for-android.md

@@ -0,0 +1,156 @@
+---
+layout: new-layouts/post
+published: false
+date: 2025-12-18 10:00:00
+title: "Exploring the Swift SDK for Android"
+author: android-workgroup
+category: "Developer Tools"
+---
+
+Since the announcement of [the preview Swift SDK for Android a couple months ago](/blog/nightly-swift-sdk-for-android/),
+the Android workgroup has seen a lot of questions about how it works and what's next.
+Please read on for some answers to common questions about the technology and its
+future.
+
+## How Swift works on Android
+
+Swift compiles directly to native machine code on Android, the same way it does on most
+other platforms. This approach produces similar performance to C and C++ code built using the
+Android Native Development Kit (NDK), while achieving a happier balance between performance,
+safety, and usability. To make this possible, Swift apps on Android bundle a native runtime
+that implements many of its features, including its standard library and core
+libraries, like Dispatch and [Foundation](/blog/foundation-preview-now-available/).
+
+However, since most Android APIs are only made available through Java and Kotlin,
+Swift must call into the Android Runtime (ART). That is where the [Java interoperability
+project's](https://github.com/swiftlang/swift-java) `jextract` and `wrap-java`
+tools come in. These tools automatically create bindings that enable you to call
+Swift from Java or go the other way using the Java Native Interface (JNI), which
+allows Swift to seamlessly integrate with the Android platform.
+
+The [`jextract` tool gained a JNI mode this summer](/blog/gsoc-2025-showcase-swift-java/):
+you can now watch its author Mads Odgaard's [Server Side Swift Conference talk from a couple months ago](https://www.youtube.com/watch?v=tOH6V1IvTAc)
+and try out [his new weather example app in the Android examples repository](
+https://github.com/swiftlang/swift-android-examples/pull/25). (editor: linking his pull
+for now, we'll swap in the link to the final directory once that example is merged later tonight PST)
+
+## Swift on Android in production
+
+While work is still ongoing on official Java interoperability, Android apps built using Swift
+have been in production for many years employing homegrown Java interop, with these apps
+collectively downloaded millions of times. Here are some notable examples:
+
+- [Spark](https://play.google.com/store/apps/details?id=com.readdle.spark) - A popular email client using Swift to share code between mobile iOS/Android and desktop macOS/Windows versions
+- [flowkey](https://play.google.com/store/apps/details?id=com.flowkey.app) - An interactive piano learning app built with Swift for Android for almost a decade
+- [MediQuo](https://play.google.com/store/apps/details?id=com.mediquo.main) - A healthcare app leveraging Swift for cross-platform development
+- [Naturitas](https://play.google.com/store/apps/details?id=com.naturitas.android) - An organic products marketplace running Swift in production
+
+## Ongoing work
+
+Grassroots community efforts to run Swift on Android [began as soon as the language source was opened in 2015](https://lists.swift.org/pipermail/swift-dev/Week-of-Mon-20151207/000171.html),
+and continue to this day. [The Android project board lists areas the workgroup determines important](https://github.com/orgs/swiftlang/projects/17),
+such as easy debugging, now a high priority for us. While it [may work for small examples](https://github.com/swiftlang/llvm-project/issues/10831),
+we need to expand and test it more and make it easy to configure and access. That will likely
+mean tying the debugger and [Swift Language Server Protocol tool, sourcekit-lsp](/blog/gsoc-2025-showcase-code-completion/),
+into Integrated Development Environments (IDEs) like [Visual Studio Code](/blog/gsoc-2025-showcase-swiftly-support-in-vscode/),
+and Android Studio, another issue on our board.
+
+[An Android workflow](https://github.com/swiftlang/github-workflows/pull/172) was
+added to the official Swift workflows for GitHub months ago, allowing you to easily
+try building your Swift packages with the Swift SDK for Android, and work is underway to let you
+[run your tests in an Android emulator](https://github.com/swiftlang/github-workflows/pull/215)
+too.
+
+We are actively looking to onboard more contributors and have set up [a video call this
+weekend to discuss](https://forums.swift.org/t/swift-on-android-new-contributors-call/83729).
+We hope to make these contributor calls a recurring event moving forward, as more people
+pitch in to improving on these Swift tools themselves.
+
+## Sharing Logic Versus Sharing UI
+
+Swift allows you to target many platforms with the same business logic, and Swift
+on Android expands that much more, but we do not provide a cross-platform GUI toolkit.
+As we write in [our draft vision document](https://github.com/swiftlang/swift-evolution/blob/807b844be42db582e434d1667fc907ae7a7a8775/visions/android.md),
+the Android workgroup has no plans to create such a GUI toolkit, but will instead
+curate a list of cross-platform UI tools from the community.
+
+See [our recent post in the Swift forums](https://forums.swift.org/t/swift-gui-toolkits-for-android/83337)
+that lists a handful of popular and in-progress options a preliminary search found, but
+which we have not yet validated regarding what their authors claim. We will work with
+those devs in the coming months to add more info on using their GUI tools with the Swift
+SDK for Android.
+
+## Android API versioning
+
+Until recently, Swift on Android did not support targeting multiple Android API levels
+in the same app, but the recent preview releases now bring the familiar `@available`
+attribute and `#available` runtime check that you know from Apple platforms to Android:
+
+```swift
+#if canImport(Android)
+import Android
+import Dispatch
+#endif
+
+@available(Android 33, *)
+func backtrace() {
+    withUnsafeTemporaryAllocation(of: UnsafeMutableRawPointer.self, capacity: 1) { address in
+        _ = backtrace(address.baseAddress!, 1)
+    }
+}
+
+@available(Android 35, *)
+func hello35() {
+    print("Hello from API 35")
+}
+
+@available(Android 27, *)
+func hello27() {
+    print("Hello, world!")
+}
+
+@main
+struct ExecutableDemo {
+
+    static func main() {
+        #if os(Android)
+          hello27()
+          if #available(Android 33, *) {
+            backtrace()
+            print("Hello from Android API 33+")
+            if #available(Android 35, *) {
+              hello35()
+            }
+          }
+        #endif
+    }
+}
+``` (editor: should we slim this down?)
+Try this new feature out on Android and let us know how it is working for you.
+
+## Learn from the community
+
+Those using Swift on Android for many years have been sharing their experiences,
+as path-breakers like [Readdle](https://readdle.com/blog/swift-for-android-our-experience-and-tools)
+and [Flowkey](https://medium.com/@ephemer/why-we-put-an-app-in-the-android-play-store-using-swift-96ac87c88dfc)
+have written about their work for the last decade. The Left Bit's Pierluigi Cifani
+[wrote about their experiences recently](https://forums.swift.org/t/thoughts-on-swift-for-android/80961),
+gave [a great talk at NSSpain 2025 a couple months ago](https://youtu.be/EIGl6GOo210),
+and was [interviewed by Swift Toolkit last month](https://www.swifttoolkit.dev/posts/dc-pier).
+
+A [community member recently contributed an example app](https://github.com/swiftlang/swift-android-examples/pull/24)
+that builds C++ using CMake and links it with Swift, using Swift's automated JNI bridging
+to Java instead. (editor: not sure we will get this in, but might be a good example to highlight for some)
+
+## Swift 6.3 SDK nightly previews
+
+Finally, we are happy to announce that [an official Swift 6.3 SDK CI](https://ci.swift.org/job/oss-swift-6.3-package-swift-sdk-for-android/)
+has been set up, and it is producing [nightly preview releases of the Swift 6.3 SDK for Android](/install/macos/#swift-sdk-buindles-dev).
+Please follow the [Getting Started guide](/documentation/articles/swift-sdk-for-android-getting-sta
+rted.html)
+to install and use it. (editor: I will update that guide by 3 AM Thursday PST with 6.3 SDK info)
+
+Swift on Android has been a community effort for the last decade, growing
+from the initial patch to apps in production and an active group of developers.
+Try out the new preview releases of the Swift 6.3 SDK for Android and help us
+make it even better!