This is the middle part of the main that is expected to cause the error. If you are not logged in on the splash screen, this code goes to MyHomePage and logs in. If you are logged in, it goes to MainScreen and switches to the main screen of the app.
class SplashScreen extends StatefulWidget {
@override
_SplashScreenState createState() => _SplashScreenState();
}
class _SplashScreenState extends State<SplashScreen> {
final FirebaseAuth auth = FirebaseAuth.instance;
final User? user = FirebaseAuth.instance.currentUser;
@override
void initState() {
super.initState();
_initUser().whenComplete((){
setState(() {});
});
}
_initUser() async {
if (auth.currentUser != null) {
Timer(
Duration(seconds: 2),
() => Navigator.of(context).pushAndRemoveUntil(
MaterialPageRoute(
builder: (context) =>
MainScreen(user!)),
(Route<dynamic> route) => false),
);
} else {
Timer(Duration(seconds: 1),
() => Navigator.of(context).pushAndRemoveUntil(
MaterialPageRoute(
builder: (context) =>
MyHomePage()),
(Route<dynamic> route) => false),
);
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Text("Splash Screen"),
),
);
}
}
This is the MyHomePage widget that is passed when you are not logged in.
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key}) : super(key: key);
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: TextButton(
onPressed: (){
FirebaseService().signup(context);
},
child: Text('Google'),
),
)
);
}
}
class FirebaseService{
final FirebaseAuth auth = FirebaseAuth.instance;
final GoogleSignIn googleSignIn = GoogleSignIn();
Future<void> signup(BuildContext context) async {
final GoogleSignInAccount? googleSignInAccount = await googleSignIn.signIn();
if (googleSignInAccount != null) {
final GoogleSignInAuthentication googleSignInAuthentication =
await googleSignInAccount.authentication;
final AuthCredential authCredential = GoogleAuthProvider.credential(
idToken: googleSignInAuthentication.idToken,
accessToken: googleSignInAuthentication.accessToken);
// Getting users credential
UserCredential result = await auth.signInWithCredential(authCredential);
User? user = result.user;
if (user != null) {
Navigator.push(
context, MaterialPageRoute(builder: (context) => MainScreen(user)));
} // if result not null we simply call the MaterialpageRoute,
// for go to the HomePage screen
}
}
Future<void> signOutFromGoogle() async{
await googleSignIn.signOut();
await auth.signOut();
}
}
This is the content of the error
The following LateError was thrown building MainScreen(dirty, dependencies: [_InheritedProviderScope<Pro?>], state: _MainScreenState#efcfa):
LateInitializationError: Field '_instance@21075166' has not been initialized.
The relevant error-causing widget was:
MainScreen MainScreen:file:///F:/flutter project/good_man/lib/main.dart:75:25
When the exception was thrown, this was the stack:
#0 ScreenUtil._instance (package:flutter_screenutil/screen_util.dart)
#1 new ScreenUtil (package:flutter_screenutil/screen_util.dart:26:12)
#2 SizeExtension.sp (package:flutter_screenutil/size_extension.dart:14:20)
#3 _MainScreenState.build (package:good_man/mainscreen.dart:45:36)
#4 StatefulElement.build (package:flutter/src/widgets/framework.dart:4904:27)
#5 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4788:15)
#6 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4962:11)
#7 Element.rebuild (package:flutter/src/widgets/framework.dart:4511:5)
#8 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2713:19)
#9 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:882:21)
#10 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:363:5)
#11 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1144:15)
#12 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1081:9)
#13 SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:862:7)
(elided 4 frames from class _RawReceivePortImpl, class _Timer, and dart:async-patch)
Below is the MainScreen code
class MainScreen extends StatefulWidget {
const MainScreen(this.user);
final User user;
@override
_MainScreenState createState() => _MainScreenState();
}
class _MainScreenState extends State<MainScreen> {
@override
Widget build(BuildContext context) {
final User user = widget.user;
final pro = Provider.of<Pro>(context);
return DefaultTabController(
length: 3,
child: Scaffold(
appBar: PreferredSize(
preferredSize: Size.fromHeight(60.0), // here the desired height
child: AppBar(
iconTheme: IconThemeData(color: Colors.black),
backgroundColor: pro.backColor_main,
elevation: 0.0,
centerTitle: true,
title: Text('aaa',
style: TextStyle(
fontFamily: 'Gugi',
fontSize: 20.sp,
color: Colors.black,
),),
),
),
drawer: Drawer(
child: ListView(
padding: EdgeInsets.zero,
children: [
DrawerHeader(
child: Text('Drawer Header'),
decoration: BoxDecoration(
color: Colors.white
),
),
ListTile(
title: Text('aaa'),
onTap: () {
Navigator.pop(context);
},
),
],
),
),
bottomNavigationBar: BottomBar(),
body: Stack(children: [
TabBarView(
children: [
MainTest(),
Text(''),
Main_User(user),
],
),
])),
);
}
}
This is the provider class
class Pro with ChangeNotifier{
late List<int> GumBool;
late List<String> Gname;
Color backColor_white1 = Color(0xffEFEFEF);
Color backColor_main = Color(0xffB5B7C3);
Color backColor_main2 = Color(0xffD3D4DD);
readyGumBool(){
GumBool =[];
GumBool = GumBool.toList();
}
setGumBool(int num){
GumBool.add(num);
}
changeGumBool(int i, int num){
GumBool[i] = num;
}
getGumBool(int num)=>GumBool[num];
readyGname(){
Gname=[];
Gname = Gname.toList();
}
setGname(String ttt) {
Gname.add(ttt);
}
getGname(int num)=>Gname[num];
}
Sorry for posting all the code without tidying up. -flutter clean -flutter upgrade -flutter create . Clear cache or emulator wipe I tried it, but it didn't work
CodePudding user response：
Please follow this documentation and add ScreenUtilInit as a root widget, specifying the size of the design draft before use, the width and height of the design draft. Example:
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
//Set the fit size (Find your UI design, look at the dimensions of the device screen and fill it in,unit in dp)
return ScreenUtilInit(
designSize: Size(360, 690),
minTextAdapt: true,
splitScreenMode: true,
builder: () =>
MaterialApp(
//... other code
builder: (context, widget) {
//add this line
ScreenUtil.setContext(context);
return MediaQuery(
//Setting font does not change with system font size
data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
child: widget,
);
},
theme: ThemeData(
textTheme: TextTheme(
//To support the following, you need to use the first initialization method
button: TextStyle(fontSize: 45.sp)
),
),
),
);
}
}
CodePudding user response：
Please, remove the delay added inside the _initUser() as this is the issue for this error.