plugin_platform_interface #

This package provides a base class for platform interfaces of federated flutter plugins.

Platform implementations should extends their platform interface class rather than implements it, as newly added methods to platform interfaces are not considered breaking changes. Extending a platform interface ensures that subclasses will get the default implementations from the base class, while platform implementations that implements their platform interface will be broken by newly added methods.

This class package provides common functionality for platform interface to enforce that they are extended and not implemented.

Sample usage: #

abstract class SamplePluginPlatform extends PlatformInterface {
  SamplePluginPlatform() : super(token: _token);

  static final Object _token = Object();

  // A plugin can have a default implementation, as shown here, or `instance`
  // can be nullable, and the default instance can be null.
  static SamplePluginPlatform _instance = SamplePluginDefault();

  static SamplePluginPlatform get instance => _instance;

  /// Platform-specific implementations should set this to their own
  /// platform-specific class that extends [SamplePluginPlatform] when they
  /// register themselves.
  static set instance(SamplePluginPlatform instance) {
    PlatformInterface.verify(instance, _token);
    _instance = instance;
  }

  // Methods for the plugin's platform interface would go here, often with
  // implementations that throw UnimplementedError.
}

class SamplePluginDefault extends SamplePluginPlatform {
  // A default real implementation of the platform interface would go here.
}