Android

The Android target produces shared libraries for arm64-v8a (devices and Apple Silicon emulators) and x86_64 (Intel emulators), plus the UniFFI-generated Kotlin bindings, in one Gradle library module the app depends on.

./nx run sdk:build:android

That target runs three steps in order:

1. cargo ndk builds libplatrium_sdk.so for both ABIs into sdk/_ffi/android/src/main/jniLibs.
2. The UniFFI generator reads the arm64 library and writes platrium_sdk.kt into sdk/_ffi/android/src/main/java (package uniffi.platrium_sdk).
3. Gradle assembles the module in sdk/_ffi/android.

The app includes this module as :platrium-sdk (project(":platrium-sdk").projectDir = file("../sdk/_ffi/android")). Rebuild the SDK whenever the Rust API changes: the Kotlin types change with it, so an API change breaks the app's build instead of failing at runtime.

Using it from Kotlin

• Async calls (createDownloadSession, streamTo, auth().exchangeCode, auth().me) are suspend functions. Cancelling the calling coroutine cancels the Rust future.
• Errors arrive as PlatriumException with the cases Unauthorized, BadRequest, ApiException and InternalException.
• Authenticated clients come from PlatriumClient.withToken(baseUrl, token). PlatriumClient(baseUrl) has no token and is only for the unauthenticated code exchange.
• File descriptors: DownloadDestination(fd) and UploadSource(fileName, fd) take a raw descriptor. The SDK takes ownership and closes it, so pass ParcelFileDescriptor.detachFd(), never a descriptor you still use.
• Progress comes from files().onTransferEvent(listener). Each call starts another subscription on the process-wide transfer manager, so subscribe once per client.
• Rust u64 arrives as Kotlin ULong.

For how the app uses these, see the Android client.