Flutter: Firebase basic Query or Basic Search code

Question

The main concept is showing documents or fields which contains the searched alphabet.

The search bar gets the given input, it send to the _firebasesearch(), but in return nothing comes out, and the above image is my database structure, trying to figure out more than a week.

CODE

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter_search_bar/flutter_search_bar.dart';

SearchBar searchBar;
GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();

class DisplayCourse extends StatefulWidget {
  @override
  _DisplayCourseState createState() => new _DisplayCourseState();
}

AppBar _buildAppBar(BuildContext context) {
  return new AppBar(
    title: new Text("FIREBASE QUERY"),
    centerTitle: true,
    actions: <Widget>[
      searchBar.getSearchAction(context),
    ],
  );
}

class _DisplayCourseState extends State<DisplayCourse> {
  String _queryText;

  _DisplayCourseState() {
    searchBar = new SearchBar(
      onSubmitted: onSubmitted,
      inBar: true,
      buildDefaultAppBar: _buildAppBar,
      setState: setState,
    );
  }

  void onSubmitted(String value) {
    setState(() {
      _queryText = value;
      _scaffoldKey.currentState.showSnackBar(new SnackBar(
        content: new Text('You have Searched something!'),
        backgroundColor: Colors.yellow,
      ));
    });
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      key: _scaffoldKey,
      appBar: searchBar.build(context),
      backgroundColor: Colors.red,
      body: _fireSearch(_queryText),
    );
  }
}

Widget _fireSearch(String queryText) {
  return new StreamBuilder(
    stream: Firestore.instance
    .collection('courses')
    .where('title', isEqualTo: queryText)
    .snapshots(),
    builder: (context, snapshot) {
      if (!snapshot.hasData) return new Text('Loading...');
      return new ListView.builder(
        itemCount: snapshot.data.documents.length,
        itemBuilder: (context, index) =>
            _buildListItem(snapshot.data.documents[index]),
      );
    },
  );
}

Widget _buildListItem(DocumentSnapshot document) {
  return new ListTile(
    title: document['title'],
    subtitle: document['subtitle'],
  );
}

the main concept is showing document sor fields which contains the searched alphabet

the search bar gets the given input, it send to the _firebasesearch(),but in return nothing comes out, and the above image is my database structure, trying to figure out more than a week,

Answer 1

This might sound a ridiculous solution but actually works so well, It's almost like the Like '%' query from SQL

In the TextField as you type a value the inside where() isGreaterThanOrEqualTowill compare it and all the string values greater than the input and If you concatinate a 'Z' At the end then isLessThan will end just after your search keyword and You get the desired Result from firestore.

// Declare your searchkey and Stream variables first
String searchKey;
Stream streamQuery;

TextField(
              onChanged: (value){
                  setState(() {
                    searchKey = value;
                    streamQuery = _firestore.collection('Col-Name')
                        .where('fieldName', isGreaterThanOrEqualTo: searchKey)
                        .where('fieldName', isLessThan: searchKey +'z')
                        .snapshots();
                  });
    }),

I used this Stream in StreamBuilder and It works exactly as expected.

Limitations:

1. The search is case sensitive(You can convert searchKey to specific case if your data is consistent like Type Case )
2. You have to start searching from the first letter, it can't search from mid

Answer 2

I'm a bit too late but I just want to share something on how I implement the search function without using third party app in my case. My solution is a bit straight forward querying using firestore. Here's the code:

Future<List<DocumentSnapshot>> getSuggestion(String suggestion) =>
  Firestore.instance
      .collection('your-collection')
      .orderBy('your-document')
      .startAt([searchkey])
      .endAt([searchkey + '\uf8ff'])
      .getDocuments()
      .then((snapshot) {
        return snapshot.documents;
      });

example if you want to search all keywords containing "ab" then it will display all words containing "ab" (ex. abcd, abde, abwe). If you want to make auto suggest search function you can use typehead. which can be found in this link: https://pub.dev/packages/flutter_typeahead

Good luck.