service_search.dart

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';

class ServiceSearchDelegate extends SearchDelegate<List<String>> {
  @override
  List<Widget> buildActions(BuildContext context) {
    return [
      IconButton(
        icon: Icon(Icons.search),
        key: ValueKey('search'),
        onPressed: () {
           ///dispatch search event and call searchServices() method.
          _dispatchServiceSearchEvent(context); 

          // to show the result built in buildResults() method         
          showResults(context);
        },
      ),
      IconButton(
        icon: Icon(Icons.clear),
        key: ValueKey('clear'),
        onPressed: () {
          //clears the textfield
          query = '';
        },
      )
    ];
  }

  @override
  Widget buildLeading(BuildContext context) {
    return IconButton(
      key: ValueKey('back'),
      icon: AnimatedIcon(
        icon: AnimatedIcons.menu_arrow,
        progress: transitionAnimation,
      ),
      onPressed: () {
        close(context, null);                 //close search delegate.
      },
    );
  }

  @override
  Widget buildResults(BuildContext context) {
    final textTheme = Theme.of(context).textTheme;
    
    //build your own list view according to you state mngt.
    return query.isEmpty
        ? SizedBox.shrink()
        : BlocBuilder<ServiceBloc, ServiceState>(
            builder: (context, state) {
              List<String> services = [];
              if (state is ServiceSearchLoading)
                return Center(child: Text('Searching for services...', style: textTheme.headline3, key: ValueKey('searching')));
              else if (state is ServiceSearchLoaded) services = state.searchedServices;

              return _buildSearchText(textTheme, services);
            },
          );
  }

  @override
  Widget buildSuggestions(BuildContext context) {
    final textTheme = Theme.of(context).textTheme;

    if (query.isEmpty) return Center(child: Text('Search services by name...', style: textTheme.headline3));

    return Container();
  }

  Widget _buildSearchText(TextTheme textTheme, List<String> services) {
    if (services.isEmpty)
      return Center(child: Text('No services found with matching name "$query".', style: textTheme.headline3));

    return ListView.builder(
      itemCount: services.length,
      itemBuilder: (context, index) => ListTile(
        onTap: () {
          close(context, services);
         // navigate to service detail screen.
        },
        title: Text(
          services[index],
          style: textTheme.headline3,
        ),
      ),
    );
  }

  void _dispatchServiceSearchEvent(BuildContext context) {
    //add event for search
    //Change this to your own implementation of bloc or provider.
    BlocProvider.of<SquadBloc>(context).add(SearchServiceEvent(index: 'services', query: query.trim().toLowerCase()));
  }
}