Creating, Publishing, and Using Flutter Packages and Plugins

During a recent mobile‑app refactor the team chose Flutter for its UI productivity, but some features require native code; sharing those features as reusable packages or plugins avoids duplicated effort across projects.

A Flutter package is a modular piece of code that can be easily shared; at minimum it contains a pubspec.yaml file with metadata and a lib folder with a public Dart file.

There are two main types: a Flutter Package (pure Dart, often providing widgets) and a Flutter Plugin (a Dart package that also includes platform‑specific implementations for Android and iOS).

Packages can be created either through the visual UI of Android Studio (Create New Flutter Project → select Flutter Package or Flutter Plugin, set name, language, etc.) or via the command line. Example commands are:

flutter create --template=package my_dart_package

flutter create --org com.example --template=plugin --platforms=android,ios -a kotlin -i swift my_plugin_package

The file structure of a pure Dart package typically includes LICENSE , README.md , CHANGELOG.md , pubspec.yaml , test/ , and lib/your_package.dart . A plugin adds platform folders such as android/src/main/java/.../FlutterPlugin , ios/Classes/FlutterPlugin.m , and an example/ app.

To publish a package you can choose pub.dev, a private Pub repository, or a Git repository. Before publishing, ensure pubspec.yaml , README.md , and CHANGELOG.md are complete. Typical fields in pubspec.yaml include name , version , description , homepage , optional publish_to , and author . Run a dry‑run with flutter packages pub publish --dry-run and publish with flutter packages pub publish .

After publishing, add the package to a project by declaring a dependency in pubspec.yaml . Version constraints can be exact, range, or open‑ended. Dependencies can also be fetched from Git, a private hosted server, or a local path, e.g.:

# from pub.dev
flutter_plugin: ^1.4.0
# from Git
flutter_plugin:
  git:
    url: https://github.com/xxxx/xxxx.git
    ref: '1.0.0'
# from private host
xes_recorder:
  hosted:
    name: xes_recorder
    url: http://pub.100tal.com
  version: 0.0.1
# local path
flutter_pub:
  path: ../

Common publishing issues include author warnings during dry‑run, Google authentication prompts, and snapshot conflicts. Work‑arounds involve using a custom mypub.dart.snapshot file and temporarily disabling Google auth, but remember to restore the original snapshot after publishing.