Flutter Amplify DataStore插件尚未添加到Amplify中

Question

突然间，我得到了错误DataStore plugin has not been added to Amplify, recoverySuggestion: Add DataStore plugin to Amplify and call configure before calling DataStore related APIs，以排除我在该页面上所做的任何工作，我在一个新页面上尝试了它，结果相同。

我已经执行了amplify codegen models、amplify pull和amplify env pull。我也试过做flutter clean，但我看不到任何变化。我真的很困惑，似乎不明白这个问题。

我在调试时注意到的一件事是，屏幕的initState似乎是在configureAmplify回调之前执行的。

我会展示代码的相关部分(很抱歉提前代码太长(。

Pubspec.yaml

dependencies:
...
amplify_flutter: ^0.2.10
amplify_datastore: ^0.2.10
amplify_api: ^0.2.10
amplify_auth_cognito: ^0.2.10
amplify_storage_s3: ^0.2.10

main.dart

import 'package:flutter/material.dart';
import 'package:my_package/screens/main/teams_screen.dart';
import 'package:my_package/services/amplify_services.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatefulWidget {
const MyApp({Key? key}) : super(key: key);
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
@override
void initState() {
super.initState();
AmplifyService.configureAmplify();
}
@override
Widget build(BuildContext context) {
...
}
}

services/amplify_services.dart

import 'package:flutter/foundation.dart';
import 'package:amplify_flutter/amplify.dart';
import 'package:amplify_datastore/amplify_datastore.dart';
import 'package:amplify_api/amplify_api.dart';
import 'package:amplify_auth_cognito/amplify_auth_cognito.dart';
import 'package:amplify_storage_s3/amplify_storage_s3.dart';
import 'package:my_package/models/ModelProvider.dart';
import 'package:my_package/amplifyconfiguration.dart';
class AmplifyService {
static configureAmplify() async {
AmplifyAPI apiPlugin = AmplifyAPI();
AmplifyAuthCognito authPlugin = AmplifyAuthCognito();
AmplifyStorageS3 amplifyStorageS3 = AmplifyStorageS3();
AmplifyDataStore dataStorePlugin = AmplifyDataStore(
modelProvider: ModelProvider.instance,
);
await Amplify.addPlugins([
dataStorePlugin,
authPlugin,
amplifyStorageS3,
apiPlugin,
]);
try {
await Amplify.configure(amplifyconfig);
} on AmplifyAlreadyConfiguredException {
if (kDebugMode) {
print(
"Amplify was already configured. Looks like app restarted on android.");
}
}
}
}

最后，甚至没有输出的非常基本的页面(screens/teams_screen.dart(

import 'dart:async';
import 'package:amplify_datastore/amplify_datastore.dart';
import 'package:amplify_flutter/amplify.dart';
import 'package:flutter/material.dart';
import 'package:my_package/models/Team.dart';
class TeamsScreen extends StatefulWidget {
const TeamsScreen({Key? key}) : super(key: key);
@override
_TeamsScreenState createState() => _TeamsScreenState();
}
class _TeamsScreenState extends State<TeamsScreen> {
late StreamSubscription<QuerySnapshot<Team>> _teamsSubscription;
bool _isLoading = true;
List<Team> teams = [];
@override
void initState() {
super.initState();
_initializeApp();
}
@override
void dispose() {
_teamsSubscription.cancel();
super.dispose();
}
Future<void> _initializeApp() async {
_teamsSubscription = Amplify.DataStore.observeQuery(Team.classType)
.listen((QuerySnapshot<Team> snapshot) {
setState(() {
if (_isLoading) _isLoading = false;
teams = snapshot.items;
});
});
}
@override
Widget build(BuildContext context) {
return Container();
}
}

Answer 1

新的一天，新鲜的头脑。问题很简单，我没有设置_isLoading状态来指示configureAmplify回调是否完成，而是让应用程序继续加载触发错误的所有其他屏幕。因此，在设置状态后，只在状态更改后添加应用程序的其余部分，它就可以正常工作了。

为了修复它，我做了以下操作：

import 'package:flutter/material.dart';
import 'package:my_package/screens/main/teams_screen.dart';
import 'package:my_package/services/amplify_services.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatefulWidget {
const MyApp({Key? key}) : super(key: key);
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
@override
void initState() {
super.initState();
_initializeApp();
}
Future<void> _initializeApp() async {
await AmplifyService.configureAmplify(); // note the await!
setState(() {
_isLoading = false; // important to set the state!
});
}
@override
Widget build(BuildContext context) {
return MaterialApp(
home: _isLoading 
? Center(child: CircularProgressIndicator())
: const MainScreen(), // _isLoading is very important here.
);
}
}