State not changing (stuck on initial) - flutter

Question

Recently i'm learning about bloc_pattern , so i follow this https://medium.com/flutter-community/implementing-bloc-pattern-for-parsing-json-from-api-5ac538d5179f .
Here is my script
My Bloc File
class HotProductBloc extends Bloc<HotProductEvent, HotProductState> {
HotProductRepository repository;
HotProductBloc({#required this.repository});
#override
HotProductState get initialState => InitialHotProductsState();
#override
Stream<HotProductState> mapEventToState(HotProductEvent event) async* {
print(event);
if (event is FetchHotProductEvent) {
yield HotProductsLoading();
try {
List<HotProducts> dataHotProduct = await repository.getHotProduct();
yield HotProductsLoaded(hotproduct: dataHotProduct);
} catch (e) {
yield HotProductsError(message: e.toString());
}
}
}
}
Repository file
abstract class HotProductRepository {
Future<List<HotProducts>> getHotProduct();
}
class HotProductImplement implements HotProductRepository {
#override
Future<List<HotProducts>> getHotProduct() async {
print("running");
final response = await http.post(Configuration.url + "api/getHotProducts",
body: {"userId": "abcde"});
if (response.statusCode == 200) {
var data = json.decode(response.body);
List<dynamic> responseData = jsonDecode(response.body);
final List<HotProducts> hotProducts = [];
responseData.forEach((singleUser) {
hotProducts.add(HotProducts(
productId: singleUser['productId'],
isNew: singleUser['isNew'],
productName: singleUser['productName'],
isHot: singleUser['isHot'],
productImage: singleUser['productImage'],
categoryId: singleUser['categoryId'],
productPrice: singleUser['productPrice'],
productDescription: singleUser['productDescription'],
isLiked: singleUser['isLiked'],
image1: singleUser['image1'],
image2: singleUser['image2'],
image3: singleUser['image3'],
productColorId: singleUser['productColorId'],
));
});
return hotProducts;
} else {
throw Exception();
}
}
Event file
abstract class HotProductEvent extends Equatable {
HotProductEvent([List props = const []]) : super(props);
}
class FetchHotProductEvent extends HotProductEvent {
#override
List<Object> get props => null;
}
State file
abstract class HotProductState extends Equatable {
HotProductState([List props = const []]) : super(props);
}
class InitialHotProductsState extends HotProductState {}
class HotProductsLoading extends HotProductState {}
class HotProductsLoaded extends HotProductState {
final List<HotProducts> hotproduct;
HotProductsLoaded({#required this.hotproduct})
: assert(hotproduct != null),
super([hotproduct]);
}
class HotProductsError extends HotProductState {
String message;
HotProductsError({#required this.message});
#override
// TODO: implement props
List<Object> get props => [message];
}
and here is how i implement the bloc
BlocListener <HotProductBloc, HotProductState>(
listener: (context, state) {
if (state is HotProductsError) {
Scaffold.of(context).showSnackBar(
SnackBar(
content: Text(state.message),
),
);
}
},
child: Container(
child: BlocBuilder<HotProductBloc, HotProductState>(
builder: (context, state) {
print("BLoc State "+ state.toString());
if (state is InitialHotProductsState) {
return Text("Siaaap");
} else if (state is HotProductsLoading) {
return Text("Loading");
} else if (state is HotProductsLoaded) {
return Text("DONE");
} else if (state is HotProductsError) {
return Text("ERROR");
}else{
return Text("Unknown error");
}
},
),
),
),
when i run my script above, i get this on my Log
I/flutter ( 390): BLoc State InitialHotProductsState I/flutter (
390): BLoc State InitialHotProductsState

Answer 1

You need to fire an event to start any change of state. Try adding this to somewhere in your build() method:
BlocProvider.of<HotProductBloc>(context).add(FetchHotProductEvent());