When Using "BlocBuilder" in "MultiBlocProvider" I have get error - flutter

Question

I am new in flutter .I am tried googling but I cant fix my problem. I used "MultiBlocProvider" for manage stats . I want change dark mode state like bellow.
ThemeCubit.dart
part 'theme_state.dart';
class ThemeCubit extends HydratedCubit<ThemeState> {
ThemeCubit() : super(ThemeState(AppThemes.lightTheme));
void getTheme(ThemeState state) {
emit(state);
}
#override
ThemeState? fromJson(Map<String, dynamic> json) {
return json['isDark'] as bool
? ThemeState(AppThemes.darkTheme)
: ThemeState(AppThemes.lightTheme);
}
#override
Map<String, bool>? toJson(ThemeState state) {
return {'isDark': state.themeData.brightness == Brightness.dark};
}
}
ThemeState.dart
part of 'theme_cubit.dart';
#immutable
class ThemeState extends Equatable {
final ThemeData themeData;
const ThemeState(this.themeData);
#override
List<Object?> get props => [themeData];
}
main.dart
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MultiBlocProvider(
providers: [
BlocProvider(
lazy: true,
create: (context) => ThemeCubit(),
),
],
child:BlocBuilder<ThemeCubit, ThemeState>(
builder: (context,state) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Flutter Production Boilerplate',
theme: state.themeData, //ThemeMode.dark,
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
},
),
);
}
}
settingScreen.dart
Positioned(
top: 60 - widget.offset / 2,
left: 20,
child: Builder(builder: (context) {
return Switch(
value:newValue ,
onChanged: (value) {
BlocProvider.of<ThemeCubit>(context).getTheme(ThemeState(
newValue ? AppThemes.darkTheme : AppThemes.lightTheme));
});
})
),
This code works properly when used "BlocProvider" . But when I used "MultiBlocProvider", I get bellow error.
The following assertion was thrown attaching to the render tree:
'package:flutter/src/widgets/framework.dart': Failed assertion: line
4357 pos 14: 'owner!._debugCurrentBuildTarget == this': is not true.
Either the assertion indicates an error in the framework itself, or we
should provide substantially more information in this error message to
help you determine and fix the underlying cause. In either case,
please report this assertion by filing a bug on GitHub:
https://github.com/flutter/flutter/issues/new?template=2_bug.md
When the exception was thrown, this was the stack:
#2 Element.rebuild. (package:flutter/src/widgets/framework.dart:4357:14)
#3 Element.rebuild (package:flutter/src/widgets/framework.dart:4360:6)
#4 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4643:5)
#5 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4638:5)
#6 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3673:14)
#7 Element.updateChild (package:flutter/src/widgets/framework.dart:3425:18)
#8 RenderObjectToWidgetElement._rebuild (package:flutter/src/widgets/binding.dart:1198:16)
#9 RenderObjectToWidgetElement.mount (package:flutter/src/widgets/binding.dart:1167:5)
#10 RenderObjectToWidgetAdapter.attachToRenderTree. (package:flutter/src/widgets/binding.dart:1112:18)
#11 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2573:19)
#12 RenderObjectToWidgetAdapter.attachToRenderTree (package:flutter/src/widgets/binding.dart:1111:13)
#13 WidgetsBinding.attachRootWidget (package:flutter/src/widgets/binding.dart:944:7)
#14 WidgetsBinding.scheduleAttachRootWidget. (package:flutter/src/widgets/binding.dart:924:7) (elided 13 frames
from class _AssertionError, class _RawReceivePortImpl, class _Timer,
dart:async, and dart:async-patch)
How can I fix it?

Answer 1

I added bellow code to ThemeCubit.dart :
bool isDarkMode = false;
ThemeMode currentTheme(){
isDarkMode?_setTheme(ThemeMode.dark) : _setTheme(ThemeMode.light);
return isDarkMode?ThemeMode.dark : ThemeMode.light;
}
void updateTheme(bool isDarkMode) {
this.isDarkMode = isDarkMode;
}
and change main.dart :
Widget build(BuildContext context) {
return MultiBlocProvider(
providers: [
BlocProvider(
create: (context) => ThemeCubit(),
),
],
child:ElderlyApp(),
);
}
class ElderlyApp extends StatefulWidget {
const ElderlyApp({Key? key,}) : super(key: key);
#override
_ElderlyAppState createState() => _ElderlyAppState();
}
class _ElderlyAppState extends State<ElderlyApp> with WidgetsBindingObserver {
#override
void initState() {
WidgetsBinding.instance!.addObserver(this);
super.initState();
}
#override
void didChangePlatformBrightness() {
context.read<ThemeCubit>().currentTheme();
super.didChangePlatformBrightness();
}
#override
void dispose() {
WidgetsBinding.instance!.removeObserver(this);
super.dispose();
}
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Production Boilerplate',
theme: AppThemes.lightTheme,
darkTheme: AppThemes.darkTheme,
themeMode: context.select(
(ThemeCubit cubit) => cubit.currentTheme()), //ThemeMode.dark,
debugShowCheckedModeBanner: false,
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
and change code in seetingScreen.dart
Positioned(
top: 60 - widget.offset / 2,
left: 20,
child: Builder(builder: (context) {
bool isDark = context.select((ThemeCubit themeCubit) =>
themeCubit.state.themeMode) ==ThemeMode.dark ? true: false;
return Switch(
value: context.read<ThemeCubit>().isDarkMode,
onChanged: (value) {
context.read<ThemeCubit>().updateTheme(value);
});
})),