android - 如何处理模型类中的 NULL SAFETY？

Question

我正在构建我的 Flutter 应用程序的模型类。我以前构建过很多 Flutter 应用程序，但这是我第一次接触 Flutter 2.0。我的类(class)如下所示。

import 'package:json_annotation/json_annotation.dart';

@JsonSerializable()
class User {
  int iduser;
  String uid;
  String first_name;
  String last_name;
  String profile_picture;
  String email;
  String phone;
  bool is_disabled;
  int created_date;
  int last_updated;

  User({this.iduser,
  this.uid,
  this.first_name,
  this.last_name,
  this.profile_picture,
  this.email,
  this.is_disabled,
  this.created_date,
  this.last_updated})
}

但是我收到每个参数的错误，如下所示。

The parameter 'iduser' can't have a value of 'null' because of its type, but the implicit default value is 'null'.
Try adding either an explicit non-'null' default value or the 'required' modifier.dart(missing_default_value_for_parameter)
{int iduser}

我知道我可以添加 required 标签等等。但大多数时候这些数据会从数据库中拉取，所以我不能确切地说出哪一个是null。然而，从数据库端来看，只有 first_name 和 email 被定义为 not-null 字段。

我应该在这里做什么？

Answer 1

尝试像下面这样改变。
(而且你最好将 snake case 变量名改为 lowerCamelCase) https://dart.dev/guides/language/effective-dart/style#do-name-other-identifiers-using-lowercamelcase

class User {
  int? iduser;
  String? uid;
  String? first_name;
  String? last_name;
  String? profile_picture;
  String? email;
  String? phone;
  bool? is_disabled;
  int? created_date;
  int? last_updated;

  User(
      {this.iduser,
      this.uid,
      this.first_name,
      this.last_name,
      this.profile_picture,
      this.email,
      this.is_disabled,
      this.created_date,
      this.last_updated});
}