Firebase Flutter 异常
Firebase Flutter 异常
我正在构建一个Flutter应用，并集成了Firebase，但当我单击按钮进行注册、登录或注销时，却一直出现这个错误。我看到其他人也问了同样的问题，但似乎没有一个适用于我。我正在使用Flutter和Android Studio。我该如何解决这个问题？
这是我的一部分代码
class HomeScreen extends StatefulWidget {
@override
_HomeScreenState createState() => _HomeScreenState();
}
class _HomeScreenState extends State {
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.red,
body: Center(
child: Container(
child: RaisedButton(
onPressed: () {
FirebaseAuth.instance.signOut().then((value) {
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) =>
LoginScreen()));
});
},
child: Text("Logout"),
)
)
)
);
}
}
以下是抛出的异常
══╡ EXCEPTION CAUGHT BY GESTURE ╞═══════════════════════════════════════════════════════════════════ The following FirebaseException was thrown while handling a gesture: [core/no-app] No Firebase App '[DEFAULT]' has been created - call Firebase.initializeApp() When the exception was thrown, this was the stack: #0 MethodChannelFirebase.app (package:firebase_core_platform_interface/src/method_channel/method_channel_firebase.dart:118:5) #1 Firebase.app (package:firebase_core/src/firebase.dart:52:41) #2 FirebaseAuth.instance (package:firebase_auth/src/firebase_auth.dart:37:47) #3 _HomeScreenState.build. (package:cosytok/screens/home.dart:20:28) #4 _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:992:19) #5 _InkResponseState.build. (package:flutter/src/material/ink_well.dart:1098:38) #6 GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:184:24) #7 TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:524:11) #8 BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:284:5) #9 BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:219:7) #10 PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:477:9) #11 PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:78:12) #12 PointerRouter._dispatchEventToRoutes. (package:flutter/src/gestures/pointer_router.dart:124:9) #13 _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:377:8) #14 PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:122:18) #15 PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:108:7) #16 GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:220:19) #17 GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:200:22) #18 GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:158:7) #19 GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:104:7) #20 GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:88:7) #24 _invoke1 (dart:ui/hooks.dart:267:10) #25 _dispatchPointerDataPacket (dart:ui/hooks.dart:176:5) (elided 3 frames from dart:async) Handler: "onTap" Recognizer: TapGestureRecognizer#f0104 ════════════════════════════════════════════════════════════════════════════════════════════════════ ════════ Exception caught by gesture ═══════════════════════════════════════════════════════════════ The following FirebaseException was thrown while handling a gesture: [core/no-app] No Firebase App '[DEFAULT]' has been created - call Firebase.initializeApp()
admin 更改状态以发布 2023年5月22日
从2020年8月17日开始更新
所有Firebase版本均已更新，现在您需要在使用任何Firebase产品之前调用Firebase.initializeApp()，例如：
首先，现在所有Firebase产品都依赖于firebase_core版本（0.5.0+），因此您需要将其添加到pubspec.yaml文件中：
dependencies:
flutter:
sdk: flutter
firebase_core : ^0.5.0
# cloud_firestore: ^0.14.0 other firebase dependencies
然后您需要调用Firebase.initializeApp()：
第一个例子
import 'package:flutter/material.dart';
// Import the firebase_core plugin
import 'package:firebase_core/firebase_core.dart';
void main() {
runApp(App());
}
class App extends StatelessWidget {
@override
Widget build(BuildContext context) {
return FutureBuilder(
// Initialize FlutterFire
future: Firebase.initializeApp(),
builder: (context, snapshot) {
// Check for errors
if (snapshot.hasError) {
return SomethingWentWrong();
}
// Once complete, show your application
if (snapshot.connectionState == ConnectionState.done) {
return MyAwesomeApp();
}
// Otherwise, show something whilst waiting for initialization to complete
return Loading();
},
);
}
}
第二个Firestore示例：
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:firebase_core/firebase_core.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: FirstRoute(title: 'First Route'),
);
}
}
class FirstRoute extends StatefulWidget {
FirstRoute({Key key, this.title}) : super(key: key);
final String title;
@override
_FirstRouteState createState() => _FirstRouteState();
}
class _FirstRouteState extends State {
@override
void initState() {
super.initState();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("test"),
),
body: FutureBuilder(
future: getData(),
builder: (context, AsyncSnapshot snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
return Column(
children: [
Container(
height: 27,
child: Text(
"Name: ${snapshot.data.data()['name']}",
overflow: TextOverflow.fade,
style: TextStyle(fontSize: 20),
),
),
],
);
} else if (snapshot.connectionState == ConnectionState.none) {
return Text("No data");
}
return CircularProgressIndicator();
},
));
}
Future getData() async {
await Firebase.initializeApp();
return await FirebaseFirestore.instance
.collection("users")
.doc("docID")
.get();
}
}
第三个例子：
在initState()中进行初始化，然后调用setState()，它将调用build()方法。
@override
void initState() {
super.initState();
Firebase.initializeApp().whenComplete(() {
print("completed");
setState(() {});
});
}
第四个例子：
在调用WidgetsFlutterBinding.ensureInitialized();之后在main()方法中进行初始化。
void main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp();
runApp(MyApp());
}