tryAuthenticateUser method

Implementation

@override
Future<String?> tryAuthenticateUser() async {
  final url = Uri.https('trello.com', '/1/authorize', {
    'expiration': 'never',
    'scope': 'read,write,account',
    'key': apiKey,
    'return_url': "$callbackScheme:/",
    'response_type': 'token',
  });

  final result = await FlutterWebAuth2.authenticate(
    url: url.toString(),
    callbackUrlScheme: callbackScheme,
  );

  final prefs = await SharedPreferences.getInstance();

  String? token = result.split('=')[1];

  if(token == null){
    return null;
  }

  await prefs.setString('token', token);
  return Future.value(token);
}