The search bar does not return any results

Question

I am trying to add a search function in my flutter app, the search bar is showing and there's not errors but its not working and it doesn't return any results. the data list is from an API that I already called using the rest API

// ignore_for_file: use_key_in_widget_constructors, avoid_print, avoid_unnecessary_containers, curly_braces_in_flow_control_structures, prefer_const_constructors, non_constant_identifier_names, unnecessary_new, avoid_function_literals_in_foreach_calls, unused_import, avoid_types_as_parameter_names, unused_label
import 'dart:convert';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:myapp2/Service_Request/SR.dart';
import 'package:myapp2/main.dart';
import 'package:myapp2/Service_Request/second.dart';
import '../Classes/demandes.dart';
import 'SR_details.dart';

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: DataFromAPI(),
    );
  }
}

class DataFromAPI extends StatefulWidget {
  @override
  _DataFromAPIState createState() => _DataFromAPIState();
}

List<Attributes> _MyAllData = [];
var _srAttributes = [];

class _DataFromAPIState extends State<DataFromAPI> {
  @override
  void initState() {
    loadData().then((value) {
      setState(() {
        _srAttributes.addAll(value);
      });
    });
    super.initState();
  }

  Future<List<Sr>> loadData() async {
    try {
      var response = await http.get(Uri.parse(
          'http://192.168.1.30:9080/maxrest/rest/mbo/sr/?_lid=azizl&_lpwd=max12345m&_format=json'));
      if (response.statusCode == 200) {
        final jsonBody = json.decode(response.body);
        Demandes data = Demandes.fromJson(jsonBody);
        final srAttributes = data.srMboSet.sr;
        return srAttributes;
      }
    } catch (e) {
      throw Exception(e.toString());
    }
    throw Exception("");
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: new Scaffold(
        appBar: AppBar(
          title: Text('Liste des Demandes'),
          leading: IconButton(
              icon: Icon(Icons.arrow_back),
              onPressed: () => Navigator.push(
                  context, MaterialPageRoute(builder: (context) => SR()))),
        ),
        body: FutureBuilder<List<Sr>?>(
          future: loadData(),
          builder: (context, snapshot) {
            if (!snapshot.hasData) {
              return CircularProgressIndicator();
            } else {
              return new ListView.builder(
                itemCount: snapshot.data?.length,
                itemBuilder: ((_, index) {
                  return index == 0
                      ? _searchbar()
                      : new ListTile(
                          title: new Card(
                            margin: new EdgeInsets.symmetric(
                                vertical: 2.0, horizontal: 8.0),
                            elevation: 10,
                            child: new ListTile(
                              title: new Column(
                                crossAxisAlignment: CrossAxisAlignment.start,
                                children: <Widget>[
                                  Padding(padding: new EdgeInsets.all(2.0)),
                                  new Text(
                                      'Ticket ID  : ${snapshot.data![index].attributes.ticketid.content}'),
                                  new Text(
                                      'status  : ${snapshot.data![index].attributes.status.content}'),
                                  new Text(
                                      'description  : ${snapshot.data![index].attributes.description?.content}'),
                                  new Text(
                                      'Reported by  : ${snapshot.data![index].attributes.reportedby.content}'),
                                  new Text(
                                      'Reoprt date : ${snapshot.data![index].attributes.statusdate.content}'),
                                ],
                              ),
                              trailing: Icon(Icons.arrow_forward_ios_rounded),
                            ),
                          ),
                          onTap: () {
                            Navigator.of(context)
                                .push(
                                  new MaterialPageRoute(
                                    builder: (BuildContext context) =>
                                        new SrDetailsScreen(
                                            sr: snapshot.data![index]),
                                  ),
                                )
                                .then((data) {});
                          });
                }),
              );
            }
          },
        ),
      ),
    );
  }

  _searchbar() {
    return Padding(
      padding: const EdgeInsets.all(8.0),
      child: TextField(
        decoration: InputDecoration(hintText: "Search ..."),
        onChanged: (text) {
          text = text.toLowerCase();
          setState(() {
            _srAttributes = _MyAllData.where((srAttributes) {
              var idticket = srAttributes.description!.content.toLowerCase();
              return idticket.contains(text);
            }).toList();
          });
        },
      ),
    );
  }
}

Answer 1

FutureBuilder loads values of current future. You are assigning a function result to FutureBuilder so its value always changes dynamically. Create variable to keep Future's value.

Future<List<Sr>>? dataToLoad;

Whenever you want to load data from server ( for example, on text changed ):

setState((){
   dataToLoad = loadData();
});

And use it in FutureBuilder:

FutureBuilder<List<Sr>?>(
      future: dataToLoad,