I have added Firebase analytics to a Flutter app, but when I try it with the debug view in Firebase, only some of the events are logged. And when a screen_view event is logged, I don't get all the information (Like firebase_screen). Even when I try to log an event with analytics.logEvent(name: 'test') it usually doesn't work.
Initially I thought the problem was that I'm using onGenerateRoute, but I have tried to use routes as well without luck.
Here is my main.dart:
import 'package:brf/route_generator.dart';
import 'package:firebase_analytics/firebase_analytics.dart';
import 'package:firebase_analytics/observer.dart';
import 'package:flutter/material.dart';
void main() => runApp(App());
class App extends StatelessWidget {
static FirebaseAnalytics analytics = FirebaseAnalytics();
static FirebaseAnalyticsObserver observer = FirebaseAnalyticsObserver(analytics: analytics);
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Title',
initialRoute: '/',
onGenerateRoute: RouteGenerator.generateRoute,
navigatorObservers: [observer],
);
}
}
And Here is RouteGenerator:
import 'package:flutter/material.dart';
import 'package:brf/screens/home.dart';
class RouteGenerator {
static Route<dynamic> generateRoute(RouteSettings settings) {
//Argument som skickas till ny sida
//final args = settings.arguments;
switch (settings.name) {
case '/':
return MaterialPageRoute(builder: (_) => Home());
break;
case '/second':
return MaterialPageRoute(builder: (_) => Second());
default:
return MaterialPageRoute(builder: (_) => _ErrorRoute());
}
}
}
And finally the screens:
import 'package:flutter/material.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
class Home extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: StreamBuilder(
stream: Firestore.instance.collection('test').snapshots(),
builder: (context, snapshot) {
if (snapshot.hasData)
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
RaisedButton(onPressed: () {
Navigator.of(context).pushNamed('/second');
}),
Text(snapshot.data.documents[0]['test']),
],
);
else
return CircularProgressIndicator();
},
),
),
);
}
}
class Second extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
);
}
}
Related
I have a Flutter application running through VS Code which does simple authentication using Firebase. Following is my full program.
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:provider/provider.dart';
import 'package:fireauth_starter/views/home_view.dart';
import 'views/login_page_view.dart';
void main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp();
runApp(FireAuthStarter());
}
class FireAuthStarter extends StatelessWidget {
//final Future<FirebaseApp> _initialisation = Firebase.initializeApp();
#override
Widget build(BuildContext context) {
//
return Provider<FirebaseAuth>(
create: (context) => FirebaseAuth.instance,
child: MaterialApp(
title: 'Firebase Authentication',
home: LandingPage(),
),
);
}
}
class LandingPage extends StatelessWidget {
const LandingPage();
#override
Widget build(BuildContext context) {
final firebaseAuth = Provider.of<FirebaseAuth>(context);
return StreamBuilder<User>(
stream: firebaseAuth.authStateChanges(),
builder: (context, AsyncSnapshot<User> snapshot) {
print(snapshot.connectionState.toString());
if (snapshot.connectionState == ConnectionState.active) {
//final bool signedIn = snapshot.hasData;
User user = snapshot.data;
return user == null ? LoginPageView() : HomeView();
//return signedIn ? DashBoard() : FirstView();
} else {
return Scaffold(
body: Center(
child: CircularProgressIndicator(),
),
);
}
});
}
}
class LoginPageView extends StatelessWidget {
#override
Widget build(BuildContext context) {
final firebaseAuth = Provider.of<FirebaseAuth>(context);
return MaterialApp(
home: Center(
child: Container(
child: TextButton(
child: Text('Sign In'),
onPressed: () {
firebaseAuth.signInWithEmailAndPassword(
email: 'myemail#email.com',
password: '1234567',
);
},
),
),
),
);
}
}
class HomeView extends StatelessWidget {
#override
Widget build(BuildContext context) {
final firebaseAuth = Provider.of<FirebaseAuth>(context);
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text('Home View'),
actions: [
TextButton(
child: Text('Sign Out'),
style: ButtonStyle(
foregroundColor: MaterialStateProperty.all<Color>(Colors.white),
),
onPressed: () {
firebaseAuth.signOut();
},
),
],
),
body: Center(
child: Container(child: Text('Home View content')),
),
),
);
}
}
The application works as expected but when I use hot reload or hot restart, app get stuck in Progress Indicator because the snapshot.connectionState returns 'ConnectionState.waiting'
https://api.flutter.dev/flutter/widgets/ConnectionState-class.html states waiting: indicating that the asynchronous operation has begun, typically with the data being null.
I though the hot restart will reset all the states and app will perform as initial load. But it doesn't. What am I missing in this?
On Flutter Web, the userChanges stream from a FirebaseAuth instance never emits the signed in user after a page reload. Instead, it only emits null. With the example below, the app gets stuck on the loading page.
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
void main() {
WidgetsFlutterBinding.ensureInitialized();
runApp(App());
}
class App extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
initialRoute: '/loading',
onGenerateRoute: (settings) {
switch (settings.name) {
case '/error':
return MaterialPageRoute(builder: (_) => ErrorScreen());
case '/loading':
return MaterialPageRoute(builder: (_) => LoadingScreen());
case '/signin':
return MaterialPageRoute(builder: (_) => SignInScreen());
case '/welcome':
return MaterialPageRoute(builder: (_) => WelcomeScreen());
default:
return MaterialPageRoute(
builder: (_) => Center(child: Text('Unknown route')));
}
},
);
}
}
class ErrorScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Center(
child: Text('An error occurred.'),
),
);
}
}
class LoadingScreen extends StatefulWidget {
#override
_LoadingScreenState createState() => _LoadingScreenState();
}
class _LoadingScreenState extends State<LoadingScreen> {
#override
void initState() {
init();
super.initState();
}
init() async {
try {
await Firebase.initializeApp();
if (kDebugMode) {
await FirebaseAuth.instance.useEmulator('http://localhost:1001');
}
final preferences = await SharedPreferences.getInstance();
bool signedIn = preferences.getBool('IS_SIGNED_IN') ?? false;
String landingPath = '/signin';
if (signedIn) {
landingPath = '/welcome';
// Wait for the userChanges to emit a non-null element.
await FirebaseAuth.instance
.userChanges()
.firstWhere((user) => user != null);
}
Navigator.of(context).pushReplacementNamed(landingPath);
} catch (error) {
print(error);
Navigator.of(context).pushReplacementNamed('/error');
}
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Center(
child: Text('Loading...'),
),
);
}
}
class SignInScreen extends StatelessWidget {
final _emailController = TextEditingController();
final _passwordController = TextEditingController();
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Column(
children: [
TextField(
controller: _emailController,
decoration: InputDecoration(labelText: 'Email address'),
),
TextField(
decoration: InputDecoration(labelText: 'Password'),
obscureText: true,
controller: _passwordController,
),
ElevatedButton(
onPressed: () => _submit(context),
child: Text('SIGN IN'),
),
],
),
),
);
}
void _submit(BuildContext context) async {
final email = _emailController.text;
final password = _passwordController.text;
FirebaseAuth.instance
.signInWithEmailAndPassword(email: email, password: password)
.then((credential) async {
final preferences = await SharedPreferences.getInstance();
await preferences.setBool('IS_SIGNED_IN', true);
Navigator.of(context).pushReplacementNamed('/welcome');
});
}
}
class WelcomeScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Column(
children: [
Text('Welcome!'),
ElevatedButton(
onPressed: () => _signOut(context),
child: Text('SIGN OUT'),
)
],
),
),
);
}
void _signOut(BuildContext context) {
FirebaseAuth.instance.signOut().then((_) async {
final preferences = await SharedPreferences.getInstance();
await preferences.setBool('IS_SIGNED_IN', false);
Navigator.of(context).pushReplacementNamed('/signin');
});
}
}
If it helps, I'm using version 8.3.0 of the Firebase Javascript libraries in my index.html file.
Am I missing something here?
It turns out the code above is fine. The issue is the emulator. Commenting out these lines of code makes the app behave as expected:
if (kDebugMode) {
FirebaseAuth.instance.useEmulator('http://localhost:1001');
}
I've filed a bug report on FlutterFire's repo about this emulator issue.
I'm trying to play a video from a URL of a Firestore Document. To play a video in Flutter, I have to instantiate its Url in the init() method. I set a default URL to a butterfly video, and the value was supposed to be replaced by the URL obtained from Firestore. (So that it is easy for me to see if the code works). However, the code does not work properly. I got an error that says "NoSuchMethodError: The getter 'value' was called on null".
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:video_player/video_player.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
void main() {
WidgetsFlutterBinding.ensureInitialized();
runApp(MyApp());
}
class MyApp extends StatelessWidget {
// Create the initialization Future outside of build
final Future<FirebaseApp> _initialization = Firebase.initializeApp();
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return FutureBuilder(
future: _initialization,
builder: (context, snapshot) {
// Check for error
if (snapshot.hasError) {
print(snapshot.error);
return Center(
child: Container(
child: Text(
"Something went wrong",
textDirection: TextDirection.ltr,
),
),
);
}
//Once complete, show your application
if (snapshot.connectionState == ConnectionState.done) {
return MaterialApp(
title: 'Flutter Demo',
home: VideoPlayerScreen(),
);
}
return CircularProgressIndicator();
});
}
}
class VideoPlayerScreen extends StatefulWidget {
#override
_VideoPlayerScreenState createState() => _VideoPlayerScreenState();
}
class _VideoPlayerScreenState extends State<VideoPlayerScreen> {
VideoPlayerController _controller;
Future<void> _initializeVideoPlayerFuture;
FirebaseFirestore firestore = FirebaseFirestore.instance;
String videoUrl =
'https://flutter.github.io/assets-for-api-docs/assets/videos/butterfly.mp4';
#override
void initState() {
firestore.collection("videos").get().then((QuerySnapshot querySnapshot) => {
querySnapshot.docs.forEach((doc) {
// _controller.dispose();
videoUrl = doc["videoUrl"];
_controller = VideoPlayerController.network(videoUrl);
_initializeVideoPlayerFuture = _controller.initialize();
print(videoUrl);
})
});
// _controller = VideoPlayerController.network(videoUrl);
// _initializeVideoPlayerFuture = _controller.initialize();
super.initState();
}
#override
void dispose() {
_controller.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Flutter Video Player"),
),
body: FutureBuilder(
future: _initializeVideoPlayerFuture,
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
return Column(
children: [
AspectRatio(
aspectRatio: _controller.value.aspectRatio,
child: VideoPlayer(_controller),
),
],
);
} else {
return Center(child: CircularProgressIndicator());
}
},
),
floatingActionButton: FloatingActionButton(
onPressed: () {
setState(() {
if (_controller.value.isPlaying) {
_controller.pause();
} else {
_controller.play();
}
});
},
child: Icon(
_controller.value.isPlaying ? Icons.pause : Icons.play_arrow,
),
),
);
}
}
Try the following:
#override
void initState() {
super.initState();
firestore.collection("videos").get().then((QuerySnapshot querySnapshot) => {
querySnapshot.docs.forEach((doc) {
videoUrl = doc["videoUrl"];
_controller = VideoPlayerController.network(videoUrl);
_initializeVideoPlayerFuture = _controller.initialize().then((_) {
// Ensure the first frame is shown after the video is initialized, even before the play button has been pressed.
setState(() {});
});
});
});
}
Since initialize() is asynchronous, then you can use the method then which will get called when the future completes. Inside the callback, you can call setState() which will trigger a rebuild and notify the framework that the internal state of the widgets has changed .
https://pub.dev/packages/video_player
Hello
I'm trying to make my first social app with Flutter and I'm stuck.
I would like to get my messages (in a conversasion between tow users) from my api.
Not a probleme when I use Future and Future Builder, but I would like the message list to update when a new message is send !
I found we can achieve it with stream, but every time I try to convert my Future In Stream, it still work, but just as if it was a Future (it never upadate on new message).
here I a simplified part of my code :
class Test extends StatelessWidget {
final Conv conv;
final User otherUser;
const Test({Key key, this.conv, this.otherUser}) : super(key: key);
Stream<List<Message>> messageFlow(String convId) {
return Stream.fromFuture(getMessages(convId));
}
Future<List<Message>> getMessages(String convId) async {
var data = await http
.post(MyApiUrl, headers: <String, String>{}, body: <String, String>{
"someParam": "param",
"id": convId,
});
var jsonData = json.decode(data.body);
List<Message> messages = [];
for (var m in jsonData) {
Message message = Message.fromJson(m);
messages.add(message);
}
return messages;
}
#override
Widget build(BuildContext context) {
return StreamBuilder(
stream: messageFlow(conv.id),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.data == null) {
return Container(
child: Center(
child: Text('Loading'),
),
);
}
return ListView.builder(
reverse: true,
controller: _messagesListController,
itemCount: snapshot.data.length,
itemBuilder: (BuildContext context, int index) {
Message message = snapshot.data[index];
var isMe = message.owner == otherUser.id ? false : true;
return _buildMessage(message, isMe);
});
});
}
}
it would be so nice if you could help me !
I'm not able to replicate your sample code, but here how I understood your question.
Let's first define the difference about Future and Streams:
From this SO post
A Future is like the token with a number on it that they give you when
you order takeout; you made the request, but the result is not yet
ready but you have a placeholder. And when the result is ready, you
get a callback (the digital board above the takeout counter shows your
number or they shout it out) - you can now go in and grab your food
(the result) to take out.
A Stream is like that belt carrying little sushi bowls. By sitting
down at that table, you've "subscribed" to the stream. You don't know
when the next sushi boat will arrive - but when the chef (message
source) places it in the stream (belt), then the subscribers will
receive it. The important thing to note is that they arrive
asynchronously (you have no idea when the next boat/message will come)
but they will arrive in sequence (i.e., if the chef puts three types
of sushi on the belt, in some order -- you will see them come by you
in that same order)
Now here is an example of how you can create your own stream from scratch:
import 'dart:async';
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
// 1st approach
final StreamController _streamController = StreamController();
addData()async{
for(int i = 1; i<= 10; i++) {
await Future.delayed(Duration(seconds: 1));
_streamController.sink.add(i);
}
}
// 2nd approach
// This approach will prevent some approach of memory leaks
Stream<int> numberStream() async*{
for(int i = 1; i<= 10; i++) {
await Future.delayed(Duration(seconds: 1));
yield i;
}
}
#override
void dispose() {
// TODO: implement dispose
super.dispose();
_streamController.close();
}
#override
void initState() {
// TODO: implement initState
super.initState();
addData();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Stream"),
),
body: Center(
child: StreamBuilder(
stream: numberStream().map((number) => "number $number"),
builder: (context, snapshot){
if(snapshot.hasError)
return Text("hey there is some error");
else if (snapshot.connectionState == ConnectionState.waiting)
return CircularProgressIndicator();
return Text("${snapshot.data}", style: Theme.of(context).textTheme.display1,);
},
)
),
);
}
}
You can also check this SO post for some references.
Here, I tweaked the sample in the SO post above to create a mini simple chat server to show how the messages updates.
import 'dart:async';
import 'package:flutter/material.dart';
class Server {
StreamController<String> _controller = new StreamController.broadcast();
void simulateMessage(String message) {
_controller.add(message);
}
Stream get messages => _controller.stream;
}
final server = new Server();
class HomeScreen extends StatefulWidget {
#override
_HomeScreenState createState() => new _HomeScreenState();
}
class _HomeScreenState extends State<HomeScreen> {
List<String> _messages = <String>[];
StreamSubscription<String> _subscription;
#override
void initState() {
_subscription = server.messages.listen((message) async => setState(() {
_messages.add(message);
}));
super.initState();
}
#override
void dispose() {
_subscription.cancel();
super.dispose();
}
#override
Widget build(BuildContext context) {
TextStyle textStyle = Theme.of(context).textTheme.display2;
return new Scaffold(
appBar: new AppBar(
title: new Text('Sample App'),
),
body: new ListView(
children: _messages.map((String message) {
return new Card(
child: new Container(
height: 100.0,
child: new Center(
child: new Text(message, style: textStyle),
),
),
);
}).toList(),
),
floatingActionButton: Column(
mainAxisAlignment: MainAxisAlignment.end,
crossAxisAlignment: CrossAxisAlignment.end,
children: [
new FloatingActionButton(
child: new Icon(Icons.account_circle_outlined),
onPressed: () {
// simulate a message arriving
server.simulateMessage('Hello World');
},
),
SizedBox(
height: 20.0,
),
new FloatingActionButton(
child: new Icon(Icons.account_circle_rounded),
onPressed: () {
// simulate a message arriving
server.simulateMessage('Hi Flutter');
},
),
],
),
);
}
}
class SampleApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new MaterialApp(
home: new HomeScreen(),
);
}
}
void main() {
runApp(new SampleApp());
}
And here are some tutorials for better references:
https://www.youtube.com/watch?v=nQBpOIHE4eE
https://www.youtube.com/watch?v=OTS-ap9_aXc
this works for me
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as HTTP;
class PeriodicRequester extends StatelessWidget {
Stream<http.Response> getRandomNumberFact() async* {
yield* Stream.periodic(Duration(seconds: 5), (_) {
return http.get("http://numbersapi.com/random/");
}).asyncMap((event) async => await event);
}
#override
Widget build(BuildContext context) {
return StreamBuilder<http.Response>(
stream: getRandomNumberFact(),
builder: (context, snapshot) => snapshot.hasData
? Center(child: Text(snapshot.data.body))
: CircularProgressIndicator(),
);
}
}
I'm currently learning Flutter and I wanted to try out Network Requests and working with Futures.
I want to show a random image from unsplash.com using their API and I want to change the image every time I press a certain button.
I tried implementing a function to change the image, but it doesn't work.
My code looks like this:
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'dart:async';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
home: RandomImage(),
);
}
}
class RandomImage extends StatefulWidget {
#override
_RandomImageState createState() => _RandomImageState();
}
class _RandomImageState extends State<RandomImage> {
static String imageUrl = 'https://source.unsplash.com/random/300x200';
Future _imgFuture = http.get(imageUrl);
void _changeImage() async {
_imgFuture = http.put(imageUrl);
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: (Text('Hello')),
),
body: Center(
child: Column(
children: [
Spacer(),
FutureBuilder(
future: _imgFuture,
builder: (context, snapshot) {
if (snapshot.hasError) {
return Text('Oops, there was an error');
} else if (snapshot.hasData) {
return Image.network(imageUrl);
} else {
return Text('No value yet');
}
},
),
RaisedButton(
child: Text('Change Image!'),
onPressed: () => setState(() {
_changeImage();
}),
),
Spacer(),
],
),
),
);
}
}
Actually, Image.network is keeping your image, for more detail to see It here. The solution for this issue is make a simple useless query to api, so the image will be identical differently in flutter.
RaisedButton(
child: Text('Change Image!'),
onPressed: () => setState(() {
// _changeImage();
imageUrl="https://source.unsplash.com/random/300x200?v=${DateTime.now().millisecondsSinceEpoch}";
}),
),
The image won't change If you call the api too frequently, you might want to add a timer to prevent user from clicking too often.
I think the problem is in the _changeImage() method, try replace http.put with http.get.