How to implement a Flutter Search App Bar

To create a search appbar, you will need a stateful widget with the following code,

Inside your State class,

  TextEditingController _searchQueryController = TextEditingController();
  bool _isSearching = false;
  String searchQuery = "Search query";

Inside Scaffold, your appbar should be like,

appBar: AppBar(
        leading: _isSearching ? const BackButton() : Container(),
        title: _isSearching ? _buildSearchField() : _buildTitle(context),
        actions: _buildActions(),
      ),

Define the required following methods for displaying and managing searchbar,

Widget _buildSearchField() {
    return TextField(
      controller: _searchQueryController,
      autofocus: true,
      decoration: InputDecoration(
        hintText: "Search Data...",
        border: InputBorder.none,
        hintStyle: TextStyle(color: Colors.white30),
      ),
      style: TextStyle(color: Colors.white, fontSize: 16.0),
      onChanged: (query) => updateSearchQuery(query),
    );
  }

  List<Widget> _buildActions() {
    if (_isSearching) {
      return <Widget>[
        IconButton(
          icon: const Icon(Icons.clear),
          onPressed: () {
            if (_searchQueryController == null ||
                _searchQueryController.text.isEmpty) {
              Navigator.pop(context);
              return;
            }
            _clearSearchQuery();
          },
        ),
      ];
    }

    return <Widget>[
      IconButton(
        icon: const Icon(Icons.search),
        onPressed: _startSearch,
      ),
    ];
  }

  void _startSearch() {
    ModalRoute.of(context)
        .addLocalHistoryEntry(LocalHistoryEntry(onRemove: _stopSearching));

    setState(() {
      _isSearching = true;
    });
  }

  void updateSearchQuery(String newQuery) {
    setState(() {
      searchQuery = newQuery;
    });
  }

  void _stopSearching() {
    _clearSearchQuery();

    setState(() {
      _isSearching = false;
    });
  }

  void _clearSearchQuery() {
    setState(() {
      _searchQueryController.clear();
      updateSearchQuery("");
    });
  }

This is the best way to implement an app searchbar in any flutter screen.

Finally, I managed to do this. This is a good starting point for the Search Show in a list. Does this are correct?

DataList.dart

List<ListWords>  listWords = [
  ListWords('oneWord', 'OneWord definition'),
  ListWords('twoWord', 'TwoWord definition.'),
  ListWords('TreeWord', 'TreeWord definition'),
];

class ListWords {
  String titlelist;
  String definitionlist;

  ListWords(String titlelist, String definitionlist) {
    this.titlelist = titlelist;
    this.definitionlist = definitionlist;
  }
}

SearchBar.dart

import 'dart:core';
import 'package:flutter/material.dart';
import 'package:test_searchbar/DataList.dart';
import 'package:test_searchbar/detail.dart';

class SearchBar extends StatelessWidget {


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Search App'),
        actions: <Widget>[
          IconButton(icon: Icon(Icons.search),
              onPressed: () {
                showSearch(context: context, delegate: DataSearch(listWords));
              })
        ],
      ),
      body: Center(
          child: Text('default content')
      ),
      drawer: Drawer(),
    );
  }
}

class DataSearch extends SearchDelegate<String> {

  final List<ListWords> listWords;

  DataSearch(this.listWords);

  @override
  List<Widget> buildActions(BuildContext context) {
    //Actions for app bar
    return [IconButton(icon: Icon(Icons.clear), onPressed: () {
      query = '';
    })];
  }

  @override
  Widget buildLeading(BuildContext context) {
    //leading icon on the left of the app bar
    return IconButton(
        icon: AnimatedIcon(icon: AnimatedIcons.menu_arrow,
          progress: transitionAnimation,
        ),
        onPressed: () {
          close(context, null);
        });
  }

  @override
  Widget buildResults(BuildContext context) {
    // show some result based on the selection
    final suggestionList = listWords;

    return ListView.builder(itemBuilder: (context, index) => ListTile(

      title: Text(listWords[index].titlelist),
      subtitle: Text(listWords[index].definitionlist),
    ),
      itemCount: suggestionList.length,
    );
  }

  @override
  Widget buildSuggestions(BuildContext context) {
    // show when someone searches for something

    final suggestionList = query.isEmpty
        ? listWords
        : listWords.where((p) => p.titlelist.contains(RegExp(query, caseSensitive: false))).toList();


    return ListView.builder(itemBuilder: (context, index) => ListTile(
      onTap: () {
        Navigator.push(
          context,
          MaterialPageRoute(
            builder: (context) => Detail(listWordsDetail: suggestionList[index]),
          ),
        );
      },
      trailing: Icon(Icons.remove_red_eye),
      title: RichText(
        text: TextSpan(
            text: suggestionList[index].titlelist.substring(0, query.length),
            style: TextStyle(
                color: Colors.red, fontWeight: FontWeight.bold),
            children: [
              TextSpan(
                  text: suggestionList[index].titlelist.substring(query.length),
                  style: TextStyle(color: Colors.grey)),
            ]),
      ),
    ),
      itemCount: suggestionList.length,
    );
  }
}

detail.dart

import 'package:flutter/material.dart';
import 'package:test_searchbar/DataList.dart';

class Detail extends StatelessWidget {

  final ListWords listWordsDetail;

  Detail({Key key, @required this.listWordsDetail}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          brightness: Brightness.dark,
          title: const Text('Détail', style: TextStyle(color: Colors.white)),
          iconTheme: IconThemeData(color: Colors.white),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text(listWordsDetail.titlelist +' (on detail page)'),
              Text(listWordsDetail.definitionlist),
            ],
          ),
        )
    );
  }
}

It would be best if the return from the detail page opens the Searchbar page with the default content and the closed searchbar ...

Scaffold(
        appBar: AppBar(
          backgroundColor: Color.fromRGBO(93, 25, 72, 1),
          toolbarHeight: 60.0,
          title: TextField(
            cursorColor: Colors.white,
            decoration: InputDecoration(
                hintText: " Search...",
                border: InputBorder.none,
                suffixIcon: IconButton(
                  icon: Icon(Icons.search),
                  color: Color.fromRGBO(93, 25, 72, 1),
                  onPressed: () {},
                )),
            style: TextStyle(color: Colors.white, fontSize: 15.0),
          ),
        ),
);

There is a ready to use widget for this:

• AppBar with search switch on pub.dev: https://pub.dev/packages/app_bar_with_search_switch

      appBar: AppBarWithSearchSwitch(
        onChanged: (text) {
          searchText.value = text;
        }, // or use: onSubmitted: (text) => searchText.value = text,
        appBarBuilder: (context) {
          return AppBar(
            title: Text('Example '),
            actions: [
              AppBarSearchButton(), // button to activate search
            ],

Here is a complete working example:

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final TextEditingController _searchController = TextEditingController();
  final List<String> _data = [
    'Apple',
    'Banana',
    'Cherry',
    'Date',
    'Fig',
    'Grape',
    'Lemon',
    'Mango',
    'Orange',
    'Papaya',
    'Peach',
    'Plum',
    'Raspberry',
    'Strawberry',
    'Watermelon',
  ];
  List<String> _filteredData = [];
  bool _isLoading = false;

  @override
  void initState() {
    super.initState();
    _filteredData = _data;
    _searchController.addListener(_performSearch);
  }

  @override
  void dispose() {
    _searchController.dispose();
    super.dispose();
  }

  Future<void> _performSearch() async {
    setState(() {
      _isLoading = true;
    });

    //Simulates waiting for an API call
    await Future.delayed(const Duration(milliseconds: 1000));

    setState(() {
      _filteredData = _data
          .where((element) => element
              .toLowerCase()
              .contains(_searchController.text.toLowerCase()))
          .toList();
      _isLoading = false;
    });
  }

  @override
  Widget build(BuildContext context) => Scaffold(
        appBar: AppBar(
          flexibleSpace: Container(
            decoration: BoxDecoration(
              gradient: LinearGradient(
                colors: [Colors.deepPurple, Colors.purple.shade300],
                begin: Alignment.topLeft,
                end: Alignment.bottomRight,
              ),
            ),
          ),
          title: TextField(
            controller: _searchController,
            style: const TextStyle(color: Colors.white),
            cursorColor: Colors.white,
            decoration: const InputDecoration(
              hintText: 'Search...',
              hintStyle: TextStyle(color: Colors.white54),
              border: InputBorder.none,
            ),
          ),
        ),
        body: _isLoading
            ? const Center(
                child: CircularProgressIndicator(color: Colors.white),
              )
            : ListView.builder(
                itemCount: _filteredData.length,
                itemBuilder: (context, index) => ListTile(
                  title: Text(
                    _filteredData[index],
                    style: const TextStyle(color: Colors.white),
                  ),
                ),
              ),
        backgroundColor: Colors.deepPurple.shade900,
      );
}

You can read more about the example here.