在bloc flutter中单击listview时，如何获取listview id？

// ListView的item类
class ListItem {
  final int id;
  final String name;

  ListItem(this.id, this.name);
}

// bloc事件类
abstract class ListViewEvent {}

class ListViewItemClickedEvent extends ListViewEvent {
  final int itemId;

  ListViewItemClickedEvent(this.itemId);
}

// bloc状态类
abstract class ListViewState {}

class ListViewLoadedState extends ListViewState {
  final List<ListItem> items;
  final int lastClickedItemId;

  ListViewLoadedState(this.items, this.lastClickedItemId);
}

// bloc类
class ListViewBloc extends Bloc<ListViewEvent, ListViewState> {
  ListViewBloc() : super(ListViewLoadedState([], 0));

  @override
  Stream<ListViewState> mapEventToState(ListViewEvent event) async* {
    if (event is ListViewItemClickedEvent) {
      yield ListViewLoadedState(state.items, event.itemId);
    }
  }
}

// 界面代码
class ListViewPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return BlocBuilder<ListViewBloc, ListViewState>(
      builder: (context, state) {
        return ListView.builder(
          itemCount: state.items.length,
          itemBuilder: (context, index) {
            final item = state.items[index];
            return ListTile(
              title: Text(item.name),
              onTap: () {
                final bloc = context.read<ListViewBloc>();
                bloc.add(ListViewItemClickedEvent(item.id));
              },
            );
          },
        );
      },
    );
  }
}