当 tring 从 firebase 检索信息时为 null

Question

我在尝试从 firebase 获取有关用户的信息时遇到问题。我正在使用 flutter。 我的应用程序适用于两种类型的用户。 对于每种类型，我都有一个全局用户文件和模型文件

用户1：

final FirebaseAuth fAuth = FirebaseAuth.instance;
User? currentFirebaseUser;
UserModel? userModelCurrentInfo;

用户2：

final FirebaseAuth fAuth = FirebaseAuth.instance;
User2? currentFirebaseUser;
User2Model? user2ModelCurrentInfo;

每种类型用户的模型类别定义如下：

class UserModel
{
  String? phone;
  String? name;
  String? id;
  String? email;
  String? user_type;

  UserModel({this.phone, this.name, this.id, this.email});
  UserModel.fromSnapshot(DataSnapshot snap)
  {
    phone = (snap.value as dynamic)["phone"];
    name = (snap.value as dynamic)["name"];
    id = snap.key;
    email = (snap.value as dynamic)["email"];
    user_type='user';

日期已完美保存在 firebase 中。我有两个节点，一个用于用户，第二个用于用户2

这是我的用户屏幕：

class TryScreen extends StatelessWidget {
  final GlobalKey<ScaffoldState> sKey = GlobalKey<ScaffoldState>();

  @override
  Widget build(BuildContext context) {
    return Scaffold(

      backgroundColor: Colors.red,
      appBar: AppBar(
        backgroundColor: Colors.red,
      ),

      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            Padding(
              padding: const EdgeInsets.only(bottom: 16.0),
              child: Text(
                'Hey'+ ' '+(userModelCurrentInfo!.name ?? '') +' ' + '👋' ,
                style: TextStyle(
                  fontSize: 20.0.sp,
                  fontWeight: FontWeight.bold,
                ),
                textAlign: TextAlign.center,
              ),
            ),
          ],
        ),
      ),
    );
  }}

使用我上面提供的用户模型。 我将提供 user2 模型：

class User2Model
{
  String? phone;
  String? name;
  String? id;
  String? email;
  String? user_type;

  User2Model({this.phone, this.name, this.id, this.email, this.user_type});
  User2Model.fromSnapshot(DataSnapshot snap)
  {
    phone = (snap.value as dynamic)["phone"];
    name = (snap.value as dynamic)["name"];
    id = snap.key;
    email = (snap.value as dynamic)["email"];
    user_type='user2';


  }
}

并尝试执行我对用户屏幕所做的操作，然后我收到错误！

有什么建议吗？有人面临同样的问题吗？

Answer 1

具体错误是什么？您还可以添加错误吗？