zstandard_android

The Android implementation of the zstandard Flutter plugin. Uses FFI and the native Zstandard C library.

Installation

Add the main plugin to your app; this package is included automatically via the federated plugin:

dependencies:
  zstandard: ^1.3.29

No extra Gradle or native setup is required for normal use.

Usage

Use the main zstandard API; the Android implementation is selected automatically on Android:

import 'package:zstandard/zstandard.dart';

void main() async {
  final zstandard = Zstandard();
  final data = Uint8List.fromList([1, 2, 3, 4, 5]);

  final compressed = await zstandard.compress(data, 3);
  final decompressed = await zstandard.decompress(compressed ?? Uint8List(0));
}

Or use the extension methods:

final compressed = await data.compress(compressionLevel: 3);
final decompressed = await compressed?.decompress();

API

ZstandardAndroid() — Creates the Android platform implementation.
compress(Uint8List data, int compressionLevel) — Compresses data (level 1–22). Returns compressed bytes or null.
decompress(Uint8List data) — Decompresses zstd-compressed data. Returns decompressed bytes or null.
getPlatformVersion() — Returns a platform identifier string.

Architecture

This package uses Dart FFI to load libzstandard_android.so and call the Zstandard C API (ZSTD_compress, ZSTD_decompress, ZSTD_compressBound, ZSTD_getFrameContentSize). Heavy work may run in a background isolate to keep the UI responsive.

Testing

From the package directory:

flutter test

Unit tests run only on Android (they are skipped on other platforms). For full integration tests, run the main zstandard example app on an Android device or emulator.

Troubleshooting

Library not found: Ensure you build and run the app for Android (e.g. flutter run or flutter build apk) so the native library is compiled and packaged.
Crashes: Verify inputs are non-null and valid; for decompress, ensure the data is a valid zstd frame.

See the documentation for more.