如果有人能帮助我发现 Flutter 应用程序中出现此错误的原因，我将不胜感激。
我认为是从数据库Stream返回的数据类型有问题
在我的应用程序中，我必须从 Firestore 的“用户”集合中检索用户信息以显示在用户配置文件屏幕中，但我收到此错误：
======== Exception caught by widgets library =======================================================
The following StateError was thrown building UserProfile(dirty, dependencies: [MediaQuery]):
Bad state: cannot get a field on a DocumentSnapshotPlatform that does not exist
The relevant error-causing widget was:
UserProfile file:///Users/JamesMontes/Documents/Flutter-projects/theloudculture/lib/pages/settings/settings_page.dart:30:28
When the exception was thrown, this was the stack:
#0 DocumentSnapshotPlatform.get (package:cloud_firestore_platform_interface/src/platform_interface/platform_interface_document_snapshot.dart:76:7)
#1 _JsonDocumentSnapshot.get (package:cloud_firestore/src/document_snapshot.dart:92:48)
#2 _JsonDocumentSnapshot.[] (package:cloud_firestore/src/document_snapshot.dart:96:40)
#3 UserProfile.build (package:theloudculture/pages/account/user_profile.dart:31:42)
#4 StatelessElement.build (package:flutter/src/widgets/framework.dart:4569:28)
...
====================================================================================================
======== Exception caught by widgets library =======================================================
Bad state: cannot get a field on a DocumentSnapshotPlatform that does not exist
The relevant error-causing widget was:
UserProfile file:///Users/JamesMontes/Documents/Flutter-projects/theloudculture/lib/pages/settings/settings_page.dart:30:28
====================================================================================================
======== Exception caught by widgets library =======================================================
Bad state: cannot get a field on a DocumentSnapshotPlatform that does not exist
The relevant error-causing widget was:
UserProfile file:///Users/JamesMontes/Documents/Flutter-projects/theloudculture/lib/pages/settings/settings_page.dart:30:28
====================================================================================================
我的文件有这个代码：
database.dart（我检索用户数据的地方）
class DatabaseService {
final String uid;
DatabaseService({this.uid});
// Get User stream
Stream<DocumentSnapshot<Map<String, dynamic>>> get user {
return usersCollection.doc(uid).snapshots();
}
}
提供流的小部件是我的主页小部件并具有以下代码：
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:theloudculture/models/user_model.dart';
import 'package:theloudculture/pages/inner_pages.dart';
import 'package:theloudculture/services/database.dart';
import 'package:theloudculture/widgets/widgets.dart';
class Home extends StatelessWidget {
@override
Widget build(BuildContext context) {
final user = Provider.of<CustomUser>(context);
return StreamProvider<DocumentSnapshot<Map<String, dynamic>>>.value(
value: DatabaseService(uid: user != null ? user.uid : null).user,
child: ChangeNotifierProvider(
create: (_) => NavegacionModel(),
child: Container(
color: Colors.black,
child: Scaffold(
backgroundColor: Colors.black,
appBar: LoudAppBar(),
body: Paginas(),
bottomNavigationBar: BottomNavBar(),
),
),
),
);
}
}
class NavegacionModel with ChangeNotifier {
int _paginaActual = 0;
int get paginaActual => this._paginaActual;
set paginaActual(int valor) {
this._paginaActual = valor;
//Notifying widgets
notifyListeners();
}
}
settings_page 是 home 小部件的子级，所以我从那个小部件访问 userData
import 'package:animate_do/animate_do.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:theloudculture/pages/account/user_profile.dart';
import 'package:theloudculture/services/auth.dart';
import 'package:theloudculture/shared/loading.dart';
import 'package:theloudculture/widgets/widgets.dart';
class SettingsPage extends StatelessWidget {
final AuthService _auth = AuthService();
@override
Widget build(BuildContext context) {
final userData =
Provider.of<DocumentSnapshot<Map<String, dynamic>>>(context);
print(userData);
return userData == null
? Loading()
: FadeIn(
duration: Duration(milliseconds: 500),
child: Container(
padding: EdgeInsets.symmetric(horizontal: 10.0),
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
Expanded(
child: UserProfile(userData: userData),
),
LargeBtn(
btnText: 'Salir',
bottomMargin: true,
btnAction: () async {
await _auth.signOut();
},
),
],
),
),
);
}
}
此外，错误提到了 UserProfile 小部件，这是代码：
import 'package:flutter/material.dart';
import 'package:theloudculture/pages/account/user_edit_page.dart';
import 'package:theloudculture/pages/account/user_profile_header.dart';
import 'package:theloudculture/shared/loading.dart';
import 'package:theloudculture/widgets/outlined_custom_button.dart';
class UserProfile extends StatelessWidget {
final userData;
const UserProfile({
Key key,
this.userData,
}) : super(key: key);
@override
Widget build(BuildContext context) {
final screenSize = MediaQuery.of(context).size;
return userData == null
? Loading()
: Container(
width: screenSize.width * 0.95,
height: screenSize.height * 0.7,
padding: EdgeInsets.only(top: 15.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
userData == null
? Loading()
: UserProfileHeader(
userUid: userData['userUid'],
userReferrerCode: userData['userReferrerCode'],
firstName: userData['firstName'],
lastName: userData['lastName'],
displayName: userData['displayName'],
email: userData['email'],
actualProfileImageName: userData['profileImageName'],
profileImageUrl: userData['profileImageUrl'],
),
Container(
padding: EdgeInsets.only(top: 15.0),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text('Amigos Invitados:'),
SizedBox(width: 10.0),
Text(userData['invitedFriends'].toString()),
],
),
SizedBox(height: 20.0),
OutlinedCustomButton(
btnText: 'Editar Perfil',
btnAction: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => UserEditPage(),
),
);
},
),
],
),
),
Expanded(
child: Container(
padding:
EdgeInsets.symmetric(vertical: 10.0, horizontal: 10.0),
child: Center(
child: Text(
'Aquí van las opciones',
style: TextStyle(color: Colors.white),
),
),
),
)
],
),
);
}
}
答案 0 :(得分：0)
由于无法发表评论，因此我将其作为答案发布。您的日志中明确指出 错误状态：无法在不存在的 DocumentSnapshotPlatform 上获取字段。您要提取的字段之一在您的数据库中不存在。
替换
Stream<DocumentSnapshot<Map<String, dynamic>>> get user {
return usersCollection.doc(uid).snapshots();
}
与
Stream<DocumentSnapshot<Map<String, dynamic>>> get user {
return FirebaseFirestore.instance.collection('users').where('uid', isEqualTo: uid).snapshots();
}