Flutter Basic to Advance Concepts!

This is a crash course to learn a few of the advanced topics in flutter using a notes app such as state management, changing themes, storing data in local storage, etc.

Final Demo video of the app:

Demo video

Getting Started

Prerequisites

Basic Knowledge about Flutter and Dart.
Flutter SDK
Android Studio or VSCode

To setup Flutter in Android Studio check here

To setup Flutter in VSCode check here

Running the app

Make sure you have the Flutter SDK installed and other prerequisites.
Fork the repository and clone it to your local machine.
Open Android Studio or VSCode and import the project.
To download the dependencies run flutter pub get at the project's root directory.
To run the app run flutter run at the project's root directory.

Features

The features are divided into 3 parts
But first, let's start with the Starter code for the app.

Starter

In the starter code there is a MyHomePage class which is the Home page, used to show the notes.
Also I have created a custom textfiled to use in other places.
And at last, there is a Note model which would contain the title and description of the note.

Below is the list of features that can be used to learn the topics.

Beginner level Features

Add date to the Note model.
Create a new screen to show the Note.title and Note.desc.
Update and delete operations for notes.
Create a Snackbar on the Update and Delete operation.
Add Slidable to denote the Update and Delete feature.
If you get stuck anywhere you can find the code here, and the guide can be found here.

Intermediate level Features

Add provider package for state management.
Separate theme data to be changed on theme toggle.
Add shared preferences package to store the theme preference.
Dynamic theme changing. (Light/Dark Theme)
If you get stuck anywhere you can find the code here, and the guide can be found here.

Advance level Features

Add sqllite database to store notes.
Add CRUD operations in the database for notes.
If you get stuck anywhere you can find the code here, and the guide can be found here.

Guide for implementing features:

Guide: Basic level Features:

Code for basic level features can be found here.
Install Packages :
- To install any package run flutter pub add <package name> in the root of the project.
- flutter_slidable
- intl

Add the date property in the Note model to store the DateTime of note creation.

After this, the constructor of the Note model will look like this: note.dart

class Note {
    final String title;
    final String desc;
    final DateTime date;

    Note({
        required this.title,
        required this.desc,
        required this.date,
    });
}

Add details.dart screen to display note details.

Navigate to details.dart file when the ListTile is pressed.

Code for details page is given below: details.dart

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

    import '../models/note.dart';

    class Details extends StatelessWidget {
        final Note note;

        const Details({
            Key? key,
            required this.note,
        }) : super(key: key);

        @override
        Widget build(BuildContext context) {
            DateFormat _dateFormat = DateFormat('hh:mm, d MMMM yy');

            return Scaffold(
            backgroundColor: Theme.of(context).backgroundColor,
            appBar: AppBar(
                backgroundColor: Theme.of(context).primaryColor,
                title: Text('Note Details!'),
            ),
            body: Center(
                child: Container(
                width: double.infinity,
                color: Theme.of(context).accentColor,
                margin: const EdgeInsets.all(16),
                padding: const EdgeInsets.all(16),
                child: Column(
                    children: [
                    Text(
                        note.title,
                        textScaleFactor: 2,
                        style: TextStyle(
                        color: Theme.of(context).primaryColor,
                        fontWeight: FontWeight.bold,
                        ),
                    ),
                    SizedBox(height: 20),
                    Text(
                        'Date: ${_dateFormat.format(note.date)}',
                        textScaleFactor: 1.3,
                        style: TextStyle(color: Theme.of(context).primaryColor),
                    ),
                    SizedBox(height: 30),
                    Text(
                        note.desc,
                        textScaleFactor: 1.2,
                        ),
                    ]),
                ),
            ),
        );
        }
    }

Add a snackbar to show on note's CRUD operations.

Docs for SnackBar class can be found here

Code for snackbar is given below:

    void snackbar(String message) {
        ScaffoldMessenger.of(context)
            .showSnackBar(SnackBar(content: Text(message)));
    }

Add Slidable as a parent widget to the ListTile and add update and delete operations to the actions and secondaryActions of the widget.

Docs for Slidable package can be found here
With update and delete features to the _notes list ie. _notes[index] = <Updated Note> and _notes.removeAt(index); respectively.
(Note: I have modified the addNote function to _addUpdateNote with optional parameters to update the note.)

After this, the ListTile with Slidable as a parent widget will look like this: home.dart

    Slidable(
    actionPane: SlidableDrawerActionPane(),
    actions: [
        IconSlideAction(
        caption: 'Update',
        color: Colors.blue,
        icon: Icons.update,
        onTap: () => _addUpdateDialog(
            title: _notes[index].title,
            desc: _notes[index].desc,
            type: 'Update',
            index: index,
            id: _notes[index].id,
        ),
        ),
    ],
    secondaryActions: [
        IconSlideAction(
        caption: 'Delete',
        color: Colors.red,
        icon: Icons.delete,
        onTap: () async {
            setState(() {
            _notes.removeAt(index);
            });
            snackbar("Deleted Note!");
        },
        ),
    ],
    child: ListTile(
        leading: Icon(
            Icons.note,
            color: Theme.of(context).primaryColor,
        ),
        title: Text(
            _notes[index].title,
            textScaleFactor: 1.2,
            style: TextStyle(fontWeight: FontWeight.bold),
        ),
        subtitle: Text(_notes[index].desc),
        trailing: Icon(
            CupertinoIcons.forward,
            color: Theme.of(context).primaryColor,
            size: 35,
        ),
        onTap: () => Navigator.push(
        context,
        MaterialPageRoute(
            builder: (context) => Details(
            note: _notes[index],
            ),
        ),
        ),
    ),
);

Finished with the Basic level Features of the app🎉.

Guide: Intermediate level Features:

Code for intermediate-level features can be found here
Install Packages :
- To install any package run flutter pub add <package name> in the root of the project.
- provider
- shared_preferences

Create a theme.dart inside the util folder for storing theme-related constants.

Add the isDark property to change the theme data of the app based on the value.

The theme.dart file will look like this: theme.dart

    import 'package:flutter/material.dart';

    class Styles {
    static ThemeData themeData({
        required bool isDark,
    }) {
        return ThemeData(
        primarySwatch: Colors.red,
        primaryColor: Colors.red,
        accentColor: isDark ? const Color(0xFF161B22) : Colors.white,
        backgroundColor:
            isDark ? const Color(0xFF010409) : const Color(0xFFEEEEEE),
        brightness: isDark ? Brightness.dark : Brightness.light,
        visualDensity: VisualDensity.adaptivePlatformDensity,
        );
    }
    }

Add dark_notifier.dart for retrieving from local storage and notify the listeners of theme change

Docs for SharedPreferences package can be found here
Docs for Provider package can be found here
More details about local storage and theming be found video.

The dark_notifier.dart file will look like this: dark_notifier.dart

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

    class DarkNotifier with ChangeNotifier {
    PrefsState _currentPrefs = const PrefsState();

    DarkNotifier() {
        _loadDarkPref();
    }

    Future<void> _loadDarkPref() async {
        await SharedPreferences.getInstance().then((prefs) {
            final bool darkPref = prefs.getBool('isDark') ?? false;
            _currentPrefs = PrefsState(darkMode: darkPref);
        });

        notifyListeners();
    }

    Future<void> _saveDarkPref() async {
        await SharedPreferences.getInstance().then((prefs) {
            prefs.setBool('isDark', _currentPrefs.darkMode);
        });
    }

    bool get isDark => _currentPrefs.darkMode;

    set darkMode(bool newValue) {
        if (newValue == _currentPrefs.darkMode) return;
            _currentPrefs = PrefsState(darkMode: newValue);
            notifyListeners();
            _saveDarkPref();
        }
    }

    class PrefsState {
        final bool darkMode;

        const PrefsState({this.darkMode = false});
    }

Changes at main.dart has to be done for state management and theming.

The main.dart file will look like this: main.dart

    void main() {
        runApp(MultiProvider(
            providers: [
            ChangeNotifierProvider(
                create: (_) => DarkNotifier(),
            ),
            ],
            child: MyApp(),
        ));
        }

        class MyApp extends StatelessWidget {
        @override
        Widget build(BuildContext context) {
            return MaterialApp(
            title: 'Flutter Workshop',
            theme: Styles.themeData(
                isDark: Provider.of<DarkNotifier>(context).isDark,
            ),
            debugShowCheckedModeBanner: false,
            home: MyHomePage(),
            );
        }
    }

Add the Switch button on the home screen for switching the theme.

Code for the Switch button is given below: home.dart

    Switch(
        value: _isDark,
        onChanged: (value) {
        _isDark = value;
        Provider.of<DarkNotifier>(context, listen: false).darkMode =
            _isDark;
        },
    ),

Congratulations! Finished with the Intermediate level Features of the app🎉.

Guide: Advanced level Features:

Code for advanced level features can be found here
Install Packages :
- To install any package run flutter pub add <package name> in the root of the project.
- sqflite
- path
Add SQlite database to store notes.
Create SQL Table in the main function in the database for storing notes.
Docs of SQlite package can be found here
Flutter example for SQlite can be found here.

Code to create table in main function is given below: main.dart

    void main() async {
        WidgetsFlutterBinding.ensureInitialized();

        await openDatabase(
            join(await getDatabasesPath(), 'notes_database.db'),
            onCreate: (db, version) {
            return db.execute(
                'CREATE TABLE note(id INTEGER PRIMARY KEY, title TEXT, desc Text, date Text)',
            );
            },
            version: 1,
        );

        runApp(MultiProvider(
            providers: [
            ChangeNotifierProvider(
                create: (_) => DarkNotifier(),
            ),
            ],
            child: MyApp(),
        ));
    }

Add CRUD operations for notes SQlite database in models/note.dart.

Add the id property inside the Note class as the primary key for the database.

Code for CRUD operations in note.dart is given below: note.dart

    import 'package:path/path.dart';
    import 'package:sqflite/sqflite.dart';

    class Note {
        final int id;
        final String title;
        final String desc;
        final DateTime date;
        static late final Future<Database> _database;

        Note({
            required this.id,
            required this.title,
            required this.desc,
            required this.date,
        });

        static Future<void> _loadDatabase() async {
            _database = openDatabase(
            join(await getDatabasesPath(), 'notes_database.db'),
            version: 1,
            );
        }

        Map<String, dynamic> toMap() {
            return {
            'id': id,
            'title': title,
            'desc': desc,
            'date': date.toString(),
            };
        }

        @override
        String toString() {
            return 'Note{id: $id, title: $title, desc: $desc, data: ${date.toString()}}';
        }

        static Future<void> insertNote(Note note) async {
            final db = await _database;

            await db.insert(
            'note',
            note.toMap(),
            conflictAlgorithm: ConflictAlgorithm.replace,
            );
            print('Note Inserted');
        }

        static Future<List<Note>> getNotes() async {
            // Get a reference to the database.
            await _loadDatabase();
            final db = await _database;

            // Query the table for all The Notes.
            final List<Map<String, dynamic>> maps = await db.query('note');
            print('Note Got');

            // Convert the List<Map<String, dynamic> into a List<Note>.
            return List.generate(maps.length, (i) {
            return Note(
                id: maps[i]['id'],
                title: maps[i]['title'],
                desc: maps[i]['desc'],
                date: DateTime.parse(maps[i]['date']),
            );
            });
        }

        static Future<void> updateNote(Note note) async {
            // Get a reference to the database.
            final db = await _database;

            // Update the given Note.
            await db.update(
            'note',
            note.toMap(),
            // Ensure that the Note has a matching id.
            where: 'id = ?',
            // Pass the Note's id as a whereArg to prevent SQL injection.
            whereArgs: [note.id],
            );
            print('Note Updated: ${note.id}');
        }

        static Future<void> deleteNote(int id) async {
            // Get a reference to the database.
            final db = await _database;

            // Remove the Note from the database.
            await db.delete(
            'note',
            // Use a `where` clause to delete a specific Note.
            where: 'id = ?',
            // Pass the Note's id as a whereArg to prevent SQL injection.
            whereArgs: [id],
            );
            print('Note Deleted: $id');
        }
    }

Check the addition of CRUD operations of note database in home.dart

Congratulations! Finished with the Advanced level Features of the app🎉.

VarunSAthreya

VarunSAthreya

Flutter Basic to Advance Concepts!

Learning basic to advance concepts in Flutter using taking Note App.

Table of contents

Flutter Basic to Advance Concepts!

Getting Started

Prerequisites

Running the app

Features

Starter

Beginner level Features

Intermediate level Features

Advance level Features

Guide for implementing features:

Guide: Basic level Features:

Guide: Intermediate level Features:

Guide: Advanced level Features:

Further reading: