android - フラッターで RIVE アニメーションを作成する方法

Question

フラッターのある RIVE アニメーションを作成したい。YouTube のチュートリアルに従いました。同じことを書いたのですが実行すると2つのエラーが表示されます

 (RiveFile.import (data);
 file.mainArtboard;)

コードは次のとおりです。

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:rive/rive.dart';


void main() {

  

runApp(MyApp());

}


class MyApp extends StatelessWidget {

  @override


  Widget build(BuildContext context) {

    return MaterialApp(

      title: 'Flutter Demo',


      home: MyPage(),
    );

  }
}

class MyPage extends StatelessWidget {


  @override

  Widget build(BuildContext context) {

    return Scaffold(

        appBar: AppBar(
          title: Text('Using Rive'),

        ),
        body: RocketContainer());
  }
}

class RocketContainer extends StatefulWidget {
  @override

  _RocketContainerState createState() => _RocketContainerState();
}


class _RocketContainerState extends State<RocketContainer> {

  Artboard _artboard;
  RiveAnimationController _rocketController;

  @override

  void initState() {
    _loadRiveFile();
    super.initState();
  }

  void _loadRiveFile() async {
    final bytes = await rootBundle.load('assets/rocket.riv');
    final file = RiveFile.import(bytes);

    setState(() {
      _artboard = file.mainArtboard;
    });
  }

  void _launch() async {
    _artboard.addController(
      _rocketController = SimpleAnimation('launch'),
    );
    setState(() => _rocketController.isActive = true);
  }

  void _fall() async {
    _artboard.addController(
      _rocketController = SimpleAnimation('fall'),
    );
    setState(() => _rocketController.isActive = true);
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        Container(
            width: MediaQuery.of(context).size.width,
            height: MediaQuery.of(context).size.height - 250,
            child: _artboard != null
                ? Rive(
                    artboard: _artboard,
                    fit: BoxFit.cover,
                  )
                : Container()),
        TextButton(onPressed: () => _launch(), child: Text('launch')),
        TextButton(onPressed: () => _fall(), child: Text('fall'))
      ],
    );
  }
}

エラー:

The current Dart SDK version is 2.10.5.
Because animation depends on cupertino_icons >=1.0.1 which requires SDK version >=2.12.0-0 <3.0.0, version solving failed.
pub get failed (1; Because animation depends on cupertino_icons >=1.0.1 which requires SDK version >=2.12.0-0 <3.0.0, version solving failed.)
*error: Instance member 'import' can't be accessed using static access. (static_access_to_instance_member at [animation] lib\main.dart:47)
*error: The getter 'mainArtboard' isn't defined for the type 'bool'. (undefined_getter at [animation] lib\main.dart:50)