When I use Bloc pattern My infinite list doesn't scroll - flutter

Question

I want to make infinite list with bloc pattern but My bloc builder works only 1 time.After scroll the page "yield" doesn't work so bloc builder doesn't build.The new items comes but state doesn't build.
deliveries_bloc.dart:
import 'dart:async';
import 'package:bloc/bloc.dart';
import 'package:equatable/equatable.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter_asten_app/data/orders_repository.dart';
import 'package:flutter_asten_app/models/order_list.dart';
import '../../locater.dart';
part 'deliveries_event.dart';
part 'deliveries_state.dart';
class DeliveriesBloc extends Bloc<DeliveriesEvent, DeliveriesState> {
final OrdersRepository ordersRepository = getIt<OrdersRepository>();
DeliveriesBloc() : super(DeliveriesInitial());
List<OrderList> orderss = [];
#override
Stream<DeliveriesState> mapEventToState(
DeliveriesEvent event,
) async* {
if (event is FetchDeliveriesEvent) {
yield DeliveriesLoadingState();
try {
final orders = await ordersRepository.getOrderList(event.page);
print(orders.length);
yield DeliveriesLoadedState(orders: orders);
} catch (_) {
yield DeliveriesErrorState();
}
} else if (event is FetchMoreDeliveriesEvent) {
try {
final orders = await ordersRepository.getMoreOrderList(event.page);
print(orders.length); //this is for check the orders length
yield DeliveriesLoadedState(orders: orders);
} catch (_) {
yield DeliveriesErrorState();
}
}
}
}
You can see in the above when my event is FetchMoreDeliveriesEvent my orders lengths icreases but the yield DeliveriesLoadedState(orders: orders); doesn't work
deliveries_state.dart:
part of 'deliveries_bloc.dart';
abstract class DeliveriesState extends Equatable {
const DeliveriesState();
}
class DeliveriesInitial extends DeliveriesState {
#override
List<Object> get props => [];
}
class DeliveriesLoadingState extends DeliveriesState {
#override
// TODO: implement props
List<Object> get props => throw UnimplementedError();
}
class DeliveriesLoadedState extends DeliveriesState {
final List<OrderList> orders;
DeliveriesLoadedState({#required this.orders});
#override
// TODO: implement props
List<Object> get props => [orders];
}
class DeliveriesErrorState extends DeliveriesState {
#override
// TODO: implement props
List<Object> get props => throw UnimplementedError();
}
deliveries_event.dart:
part of 'deliveries_bloc.dart';
abstract class DeliveriesEvent extends Equatable {
const DeliveriesEvent();
}
class FetchDeliveriesEvent extends DeliveriesEvent {
final int page;
FetchDeliveriesEvent({#required this.page});
#override
// TODO: implement props
List<Object> get props => [page];
}
class FetchMoreDeliveriesEvent extends DeliveriesEvent {
final int page;
FetchMoreDeliveriesEvent({#required this.page});
#override
// TODO: implement props
List<Object> get props => [page];
}
the part of Main_page
Expanded(
child: BlocBuilder<DeliveriesBloc, DeliveriesState>(
bloc: _ordersBloc,
builder: (context, DeliveriesState state) {
if (state is DeliveriesLoadingState) {
return Center(
child: CircularProgressIndicator(),
);
}
if (state is DeliveriesLoadedState) {
return ListView.builder(
controller: _scrollController,
itemCount: state.orders.length,
itemBuilder: (context, index) {
return Card(
elevation: 4,
child: ListTile(
title: Text(state.orders[index].firadi),
subtitle: Text(state.orders[index].sidttr
.toString()),
),
);
});
} else {
return null;
}
},
),
),

Answer 1

Bloc builder re-build the widgets only if its content changes. Make sure you are providing your change detectable variables to your equatable's props getter.
If your OrderList class is not extending from Equatable, the orders fields change won't be reflected in state.
Check if you extended your OrderList class with Equatable, if yes make sure you added its props as well.