How to display a Cubit state modified in a Widget into another Widget? - flutter

Question

Im developing a Shopping cart using the BLoC pattern and I got stuck trying to learn the subset Cubit. My main question is how can I display the state of a previously updated Cubit? My flow is the next...
On the Product Screen I increase/decrease the items I want to use.
To push to change the state, I click a button and send the items as a parameter to the Cubit function.
The item list gets updated and I want to get it into another widget that is outside of the Product Screen.
Here is the code:
main.dart
void main() {HttpOverrides.global = new MyHttpOverrides();
runApp(
RepositoryProvider<AuthenticationService>(
create: (context) {
return AuthService();
},
child: MultiBlocProvider(
providers: [
BlocProvider<AuthenticationBloc>(
create: (context) {
final authService = RepositoryProvider.of<AuthenticationService>(context);
return AuthenticationBloc(authService)..add(AppLoaded());
}
),
BlocProvider<CartCubit>(create: (context) => CartCubit())
],
child: MyApp(),
),
)
);
}
product_screen.dart
BlocBuilder<CartCubit, List<Item>>(
builder: (context, state) {
return Row(
children: [
_shoppingItem(0),
SizedBox(
width: SizeConfig.blockSizeHorizontal * 2,
),
Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.all(Radius.circular(10.0)),
color: Color(0xFF48AD71),
),
child: IconButton(
onPressed: () {
for (int i = 1; i <= counter; i++) {
items.add(widget.item);
print('something');
}
context.read<CartCubit>().addToList(items);
},
icon: Icon(
Icons.shopping_bag),
color: Colors.white,
),
),
],
);
},
)
cart_cubit.dart
class CartCubit extends Cubit<List<Item>> {
CartCubit() : super([]);
void addToList(List<Item> items) {
state.addAll(items);
emit(state);
print(state);
}
}
What I should add on my Cart Screen so I can get the value of the Cubit State? Also, do this should be better handled by using a bloc instead of cubit?
Edit: Based on the comment of Loren.A I removed the BlocBuilder of my ProductScreen and I added it to my CartScreen.
class _CartScreenState extends State<CartScreen> {
#override
Widget build(BuildContext context) {
SizeConfig().init(context);
return SingleChildScrollView(
child: BlocBuilder<CartCubit, List<Item>>(
builder: (context, state) {
return Column()
...
...
Align(
alignment: Alignment.topRight,
child: Text(
state.length.toString(), // this is not updating
textAlign: TextAlign.end,
style: TextStyle(
fontFamily: 'SinkinSans',
fontSize: 12.0,
fontWeight: FontWeight.w400,
color: Color(0xFFC9C9C9)),
),
),

Answer 1

Cubit is fine for this. You can update widgets anywhere in your app based on that list just by adding another BlocBuilder<CartCubit, List<Item>>. So just add another one to your Cart page and do what ya gotta do inside of it. It will reflect the previous changes.
Edit: Just noticed that it doesn't appear that you're actually rebuilding any widgets in your product screen so that BlocBuilder you have is not really doing anything. You can remove that and just use it where you need to reflect that value of the list. You can still fire that addToList method without being inside a BlocBuilder.