Flutter将数据发送到新路由，说明参数未定义

class NewRoute extends StatelessWidget {
  final String message;

  NewRoute({required this.message});

  //...
}

Navigator.push(
  context,
  MaterialPageRoute(
    builder: (context) => NewRoute(message: "Hello Flutter"),
  ),
);

class NewRoute extends StatelessWidget {
  final String message;

  NewRoute({required this.message});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('New Route'),
      ),
      body: Center(
        child: Text(message),
      ),
    );
  }
}