Suppose I have Form in screen A with save button that run post action in cubit:
Future<void> postAssignment(List<Assigment?> assignments) async {
emit(state.copyWith(status: AssignmentStatus.posting));
try {
await _warehouseRepository.postAssignments(
assignments.map((a) => AssigmentApi.Assigment.toApi(a!)).toList());
emit(state.copyWith(status: AssignmentStatus.success));
} on Exception catch (e) {
print("Error message: ${e.toString()}");
emit(state.copyWith(status: AssignmentStatus.failure));
}
}
After this I want to stay in screen A with reseting state and I want to show snackBar that item is posted. So I have BlocListener for it:
BlocListener<AssignmentCubit, AssignmentState>(
listener: (context, state) async {
print('AssignmentCubit-------------->: $state');
if (state.status.isPosting) {
AppKeys.NAVIGATOR_KEY.currentState?.pushNamed(
SplashPage.routeName,
);
}
if (state.status.isSuccess) {
await context.read<ViewItemCubit>().fetchViewItems(
int.parse(
context.read<ItemBarcodeCubit>().state,
),
);
final snackBar = SnackBar(
duration: Duration(seconds: 2),
content: Text('added'),
backgroundColor: Colors.green,
);
ScaffoldMessenger.of(context).showSnackBar(snackBar);
} else {
AppKeys.NAVIGATOR_KEY.currentState?.popUntil(
(route) =>
route.settings.name == ItemLocatePage.routeName,
);
}
},
),
but I think the state isn't reset and it's stacking, this is the result if I post first item:
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.posting, [])
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.success, [])
second item:
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.posting, [])
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.posting, [])
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.success, [])
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.success, [])
and so on:
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.posting, [])
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.posting, [])
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.posting, [])
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.success, [])
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.success, [])
I/flutter (30679): AssignmentCubit-------------->: AssignmentState(AssignmentStatus.success, [])
thanks to this the snackBar appears 3 times. Generally, I think the problem is in Navigator, because If I posted item the state isn't reset (maybe screen isn't dispose?). What is wrong?
Edit: build method:
@override
Widget build(BuildContext context) {
return WillPopScope(
onWillPop: () {
AppKeys.NAVIGATOR_KEY.currentState?.pushNamedAndRemoveUntil(
HomePage.routeName,
(route) => false,
);
return Future.value(true);
},
child: BlocBuilder<ViewItemFormCubit, ViewItem?>(
builder: (context, state) {
final dropdownValue =
context.read<ViewItemFormCubit>().state == ViewItem.empty()
? null
: context.read<ViewItemFormCubit>().state;
return MultiBlocListener(
listeners: [
BlocListener<ViewItemCubit, ViewItemState>(
listener: (context, state) {
if (state.status.isLoading) {
AppKeys.NAVIGATOR_KEY.currentState?.pushNamed(
SplashPage.routeName,
);
} else {
AppKeys.NAVIGATOR_KEY.currentState?.popUntil(
(route) =>
route.settings.name == ItemLocatePage.routeName,
);
}
},
),
BlocListener<AssignmentCubit, AssignmentState>(
listener: (context, state) async {
print('AssignmentCubit-------------->: $state');
if (state.status.isPosting) {
AppKeys.NAVIGATOR_KEY.currentState?.pushNamed(
SplashPage.routeName,
);
}
if (state.status.isSuccess) {
await context.read<ViewItemCubit>().fetchViewItems(
int.parse(
context.read<ItemBarcodeCubit>().state,
),
);
final snackBar = SnackBar(
duration: Duration(seconds: 2),
content: Text('added'),
backgroundColor: Colors.green,
);
ScaffoldMessenger.of(context).showSnackBar(snackBar);
} else {
AppKeys.NAVIGATOR_KEY.currentState?.popUntil(
(route) =>
route.settings.name == ItemLocatePage.routeName,
);
}
},
),
],
child: Scaffold(
appBar: AppBar(
leading: IconButton(
icon: Icon(Icons.arrow_back),
onPressed: () {
_clearAllItemsInList();
AppKeys.NAVIGATOR_KEY.currentState?.pushNamedAndRemoveUntil(
HomePage.routeName, (route) => false);
},
),
title: Text(
'Locate item ${context.read<ItemBarcodeCubit>().state}'),
centerTitle: true,
),
floatingActionButton: Padding(
padding: const EdgeInsets.only(bottom: 40, right: 20),
child: FloatingActionButton(
onPressed: () => scanBarcodeNormal(dropdownValue),
child: Icon(
const IconData(0xefe1, fontFamily: 'MaterialIcons'),
size: 35.0,
),
backgroundColor: Color(0xff33691e),
foregroundColor: Colors.white,
),
),
body: Center(
child: Form(
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
children: [
SizedBox(
height: 20,
),
Padding(
padding: const EdgeInsets.all(8.0),
child: DropdownButtonFormField<ViewItem>(
decoration: InputDecoration(
filled: true,
labelText: 'Item',
),
value: dropdownValue,
icon: const Icon(Icons.arrow_downward),
elevation: 16,
items: context
.read<ViewItemCubit>()
.state
.viewItems
?.map<DropdownMenuItem<ViewItem>>(
(item) {
return DropdownMenuItem<ViewItem>(
value: item,
child: Text(
'${item.itemId}. ${item.materialNumber} ${item.materialDescription}',
),
);
},
).toList(),
onChanged: (ViewItem? newValue) {
_clearAllItemsInList();
context.read<ViewItemFormCubit>().set(newValue!);
},
),
),
BlocBuilder<AssigmentItemsCubit, AssigmentItemsState>(
builder: (context, state) {
return Expanded(
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
children: [
Container(
decoration: BoxDecoration(
color: Colors.white,
borderRadius:
BorderRadius.all(Radius.circular(5)),
boxShadow: [
BoxShadow(
color: Colors.grey.withOpacity(0.2),
spreadRadius: 5,
blurRadius: 15,
offset: Offset(0, 10),
),
],
),
child: dropdownValue != null
? Text(
'Left to assign: ${dropdownValue.totalQuantity - dropdownValue.assignedQuantity - context.read<AssigmentItemsCubit>().state.items.fold(
0,
(acc, item) {
return acc + item!.quantity;
},
)}',
style: TextStyle(fontSize: 20),
)
: Text(''),
),
AssigmentItems(
locationListKey: locate_list_key,
),
],
),
);
},
),
ElevatedButton(
onPressed: () {
final assignments =
context.read<AssigmentItemsCubit>().state.items;
context
.read<AssignmentCubit>()
.postAssignment(assignments);
_clearAllItemsInList();
},
child: Text('Save'),
)
],
),
),
),
),
);
},
),
);
I solved this by code:
BlocListener<AssignmentCubit, AssignmentState>(
listener: (context, state) async {
print('AssignmentCubit-------------->: $state');
if (state.status.isPosting) {
AppKeys.NAVIGATOR_KEY.currentState?.pushReplacementNamed(
SplashPage.routeName,
);
}
if (state.status.isSuccess) {
await context.read<ViewItemCubit>().fetchViewItems(
int.parse(
context.read<ItemBarcodeCubit>().state,
),
);
final snackBar = SnackBar(
duration: Duration(seconds: 2),
content: Text('added'),
backgroundColor: Colors.green,
);
ScaffoldMessenger.of(context).showSnackBar(snackBar);
}
if (state.status.isInitial) {
AppKeys.NAVIGATOR_KEY.currentState?.pushNamed(
ItemLocatePage.routeName,
);
}
},
),
FYI, look out what you have in your Navigator stack, in my example I had previous screen with BlocListener and from here I pushed screen A but previous screen (with BlocListener) didn't dispose so it also listened changes in my screen A. It was hard to diagnose what was going on.