Firestore with StreamBuilder
Question
I want to use Firestore with StreamBuilder. But i get error:
No Firebase App '[DEFAULT]' has been created - call Firebase.initializeApp()
The relevant error-causing widget was:
Kutuphane file:///C:/Users/burak/Desktop/flutter_ornekler/mto/lib/main/main.dart:44:26
44:26 is Kutuphane _kutuphane = ( this point )Kutuphane();
I added 2 photos to the bottom. Please check it.
I added these codes but i'm getting same error:
bool USE_FIRESTORE_EMULATOR = false;
void main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp();
runApp(MyApp());
if (USE_FIRESTORE_EMULATOR) {
FirebaseFirestore.instance.settings = Settings(
host: 'localhost:8080', sslEnabled: false, persistenceEnabled: false);
}
}
You should comment out some lines code. I didn't share irrelevant codes.
main.dart
bool USE_FIRESTORE_EMULATOR = false;
void main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp();
runApp(MyApp());
if (USE_FIRESTORE_EMULATOR) {
FirebaseFirestore.instance.settings = Settings(
host: 'localhost:8080', sslEnabled: false, persistenceEnabled: false);
}
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: HomePage(),
);
}
}
class HomePage extends StatefulWidget {
@override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
Duyurular _duyurular = Duyurular();
Dergiler _dergiler = Dergiler();
Anasayfa _anasayfa = Anasayfa();
CanliDersler _canliDersler = CanliDersler();
Kutuphane _kutuphane = Kutuphane();
Widget _showPage = new Anasayfa();
int _iconColorNumber = 2;
int _iconSize = 2;
Widget _pageChooser(int page) {
switch (page) {
case 0:
return _duyurular;
break;
case 1:
return _dergiler;
break;
case 2:
return _anasayfa;
break;
case 3:
return _canliDersler;
break;
case 4:
return _kutuphane;
break;
default:
return new Container(
child: new Center(
child: new Text(
"Sayfa bulunamadı..",
style: new TextStyle(fontSize: 30),
),
),
);
}
}
nested() {
return NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return [
SliverAppBar(
toolbarHeight: 50,
expandedHeight: 92.0,
floating: false,
pinned: true,
flexibleSpace: FlexibleSpaceBar(
background: Image.asset(
"assets/images/besmele.jpg",
fit: BoxFit.cover,
),
),
actions: [
IconButton(
icon: Icon(Icons.account_circle),
color: Colors.white,
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => ProfilAppBarli()));
},
),
],
)
];
},
body: Container(
child: Center(
child: _showPage,
),
));
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: nested(),
drawer: Drawer(
child: DrawerDosyasi(),
),
bottomNavigationBar: CurvedNavigationBar(
color: Colors.blue,
backgroundColor: Colors.white,
buttonBackgroundColor: Colors.blue,
height: 50,
index: 2,
items: <Widget>[
Icon(
Icons.campaign,
size: _iconSize == 0 ? 30 : 20,
color: _iconColorNumber == 0 ? Colors.orange : Colors.white,
),
Icon(
Icons.library_books,
size: _iconSize == 1 ? 30 : 20,
color: _iconColorNumber == 1 ? Colors.orange : Colors.white,
),
Icon(
Icons.home,
size: _iconSize == 2 ? 30 : 20,
color: _iconColorNumber == 2 ? Colors.orange : Colors.white,
),
Icon(
Icons.video_collection_rounded,
size: _iconSize == 3 ? 30 : 20,
color: _iconColorNumber == 3 ? Colors.orange : Colors.white,
),
Icon(
Icons.menu_book_rounded,
size: _iconSize == 4 ? 30 : 20,
color: _iconColorNumber == 4 ? Colors.orange : Colors.white,
),
],
animationDuration: Duration(
milliseconds: 300,
),
animationCurve: Curves.bounceInOut,
onTap: (int tappedIndex) {
setState(() {
_showPage = _pageChooser(tappedIndex);
_iconColorNumber = tappedIndex;
_iconSize = tappedIndex;
});
},
),
);
}
}
kutuphane.dart
class KutuphaneAppBarli extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
home: Scaffold(
appBar: AppBar(
toolbarHeight: 50,
leading: IconButton(
onPressed: () {
Navigator.pop(context);
},
icon: const Icon(Icons.arrow_back_rounded),
),
title: Text("Kütüphane"),
elevation: 0,
backgroundColor: Colors.blue,
),
body: Kutuphane()),
);
}
}
class Kutuphane extends StatelessWidget {
@override
Widget build(BuildContext context) {
return StreamBuilder(
stream: FirebaseFirestore.instance.collection("kutuphane").snapshots(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.hasError) {
return Center(
child:
Text("Bir şeyler ters gitti. \n Hata : \n ${snapshot.error}"),
);
}
if (snapshot.connectionState == ConnectionState.waiting) {
return Center(
child: Text("Sayfa yükleniyor.."),
);
}
return ListView(
children: snapshot.data.docs
.map((doc) => ListTile(
title: Text(doc["ListeAdi"]),
subtitle: Text(
"Okunan Kitap Sayısı : ${doc["OkunanKitapSayisi"]}")))
.toList(),
);
},
);
}
}
pubspec.yaml
name: mto
description: A new Flutter application.
# The following line prevents the package from being accidentally published to
# pub.dev using `pub publish`. This is preferred for private packages.
publish_to: 'none' # Remove this line if you wish to publish to pub.dev
# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0+1
environment:
sdk: ">=2.7.0 <3.0.0"
dependencies:
flutter:
sdk: flutter
cloud_firestore: ^0.14.3
firebase_database: ^4.3.0
page_transition: ^1.1.7+2
simple_animations: ^2.2.3
curved_navigation_bar: ^0.3.4
provider: ^4.3.2+2
shared_preferences: ^0.5.12+4
flutter_launcher_icons: ^0.8.1
firebase_core: ^0.5.2
# The following adds the Cupertino Icons font to your application.
# Use with the CupertinoIcons class for iOS style icons.
cupertino_icons: ^1.0.0
dev_dependencies:
flutter_test:
sdk: flutter
flutter_icons:
android: "launcher_icon"
ios: true
image_path: "assets/images/mto_logo.png"
# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/tools/pub/pubspec
# The following section is specific to Flutter.
flutter:
# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.
uses-material-design: true
# To add assets to your application, add an assets section, like this:
assets:
- assets/images/
# - images/a_dot_ham.jpeg
# An image asset can refer to one or more resolution-specific "variants", see
# https://flutter.dev/assets-and-images/#resolution-aware.
# For details regarding adding assets from package dependencies, see
# https://flutter.dev/assets-and-images/#from-packages
# To add custom fonts to your application, add a fonts section here,
# in this "flutter" section. Each entry in this list should have a
# "family" key with the font family name, and a "fonts" key with a
# list giving the asset and other descriptors for the font. For
# example:
# fonts:
# - family: Schyler
# fonts:
# - asset: fonts/Schyler-Regular.ttf
# - asset: fonts/Schyler-Italic.ttf
# style: italic
# - family: Trajan Pro
# fonts:
# - asset: fonts/TrajanPro.ttf
# - asset: fonts/TrajanPro_Bold.ttf
# weight: 700
#
# For details regarding fonts from package dependencies,
# see https://flutter.dev/custom-fonts/#from-packages
1 answers
solution1
2 2020-11-20 18:21:21
I solved the problem. I made the stateless widget in the "kutuphane" file stateful.
I don't know why it fixes.
class KutuphaneAppBarli extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
home: Scaffold(
appBar: AppBar(
toolbarHeight: 50,
leading: IconButton(
onPressed: () {
Navigator.pop(context);
},
icon: const Icon(Icons.arrow_back_rounded),
),
title: Text("Kütüphane"),
elevation: 0,
backgroundColor: Colors.blue,
),
body: Kutuphane()),
);
}
}
class Kutuphane extends StatefulWidget {
@override
_KutuphaneState createState() => _KutuphaneState();
}
class _KutuphaneState extends State<Kutuphane> {
bool _initialized = false;
bool _error = false;
void initializeFlutterFire() async {
try {
// Wait for Firebase to initialize and set `_initialized` state to true
await Firebase.initializeApp();
setState(() {
_initialized = true;
});
} catch (e) {
// Set `_error` state to true if Firebase initialization fails
setState(() {
_error = true;
});
}
}
@override
void initState() {
initializeFlutterFire();
super.initState();
}
@override
Widget build(BuildContext context) {
if (_error) {
return Center(
child: Text("Bir şeyler ters gitti. \n Hata : \n $_error"),
);
}
if (!_initialized) {
return Center(
child: Text(""),
);
}
return StreamBuilder<QuerySnapshot>(
stream: FirebaseFirestore.instance
.collection('kutuphane')
.snapshots(includeMetadataChanges: true),
builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
if (snapshot.hasError) {
return Center(
child:
Text("Bir şeyler ters gitti. \n Hata : \n ${snapshot.error}"),
);
}
if (!snapshot.hasData) {
return Center(
child: Text(""),
);
}
if (snapshot.connectionState == ConnectionState.waiting) {
return Center(
child: Text(""),
);
}
return new ListView(
children: snapshot.data.docs
.map((doc) => ListTile(
title: new Text(doc["ListeAdi"]),
subtitle: new Text(
"Okunan Kitap Sayısı : ${doc["OkunanKitapSayisi"]}")))
.toList(),
);
},
);
}
}
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.
Related Question
Flutter Firestore - Streambuilder within a streambuilder
StreamBuilder Firestore Pagination
StreamBuilder Controls and Firestore Pricing
Flutter Firestore and StreamBuilder
StreamBuilder with Firestore loading vs no data
Flutter Firestore StreamBuilder on list of references
Flutter with Firestore: StreamBuilder vs StreamProvider
flutter firestore pagination using streambuilder
Cloud firestore read count in StreamBuilder
How to refresh streambuilder in firestore query?
Related Tags