Flutter Course: Completing the Lotto App UI

Hello! In this course, we will take a detailed look at how to complete the user interface (UI) of a lottery app using Flutter. This course will be beneficial for everyone, from those who are new to Flutter to those who have experience. Of course, if you have learned the basic concepts and components of Flutter through previous courses, you will find it easier to follow along.

Table of Contents

1. Overview

We will implement a feature that allows users to easily generate and verify numbers through the lottery app. The lottery app requires a simple UI and user-friendly design. This will enable users to generate and easily check their lottery numbers. In this course, we will complete the UI of the lottery app and add basic lottery number generation functionality.

2. Environment Setup

The process of installing and setting up Flutter is as follows:

  1. Download and install the Flutter SDK.
  2. You can use VS Code or Android Studio as your IDE. This course will focus on Android Studio.
  3. Set up the emulator in Android Studio.
  4. Create a Flutter project and install the necessary plugins.

3. Project Creation

Now, let’s create a new Flutter project. Open Android Studio and follow these steps:

  1. Select New > New Flutter Project from the File menu.
  2. Select Flutter Application and then click Next.
  3. Enter the Project Name, Project Location, etc., and click Finish.

The basic structure of the Flutter project has now been created. Please open the main.dart file.

4. UI Components

The UI of the lottery app consists of the following key components:

  • App Bar: Includes the title and menu of the app.
  • Number Selection Area: The area that displays the randomly generated lottery numbers.
  • Button: A button is needed to generate the numbers.

Now, let’s write the code to configure the UI. Below is the basic UI layout:


import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Lottery Number Generator',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: LottoHome(),
    );
  }
}

class LottoHome extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Lottery Number Generator'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(
              'Generated Numbers:',
              style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
            ),
            // Number output section
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () {},
              child: Text('Generate Numbers'),
            ),
          ],
        ),
      ),
    );
  }
}

The code above sets up the basic app structure and places the app bar and button.

5. Design Principles

The most important point in UI design is to consider the user experience. You should create an intuitive UI that users can easily understand and use. You must adhere to the following design principles:

  • Consistency: The colors, button styles, etc., used in all screens should be consistently maintained.
  • Accessibility: You need to consider accessibility so that all users can easily use the app.
  • Clarity: All elements of the app should be clearly displayed and should not confuse the user.

6. Required Packages

You can use several packages to generate lottery numbers. For example, you can use a package like random_number. To do this, add the following to the pubspec.yaml file:


dependencies:
  flutter:
    sdk: flutter
  random_number: ^1.0.0

This package allows you to generate random numbers. After adding the package, install it using the flutter pub get command.

7. Implementing the Lottery Number Generator

Now, we will implement the function to randomly generate lottery numbers. We will modify the code so that numbers are generated when the button is clicked:


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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Lottery Number Generator',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: LottoHome(),
    );
  }
}

class LottoHome extends StatefulWidget {
  @override
  _LottoHomeState createState() => _LottoHomeState();
}

class _LottoHomeState extends State {
  List _lottoNumbers = [];

  void _generateLottoNumbers() {
    final Random random = Random();
    _lottoNumbers = List.generate(6, (index) => random.nextInt(45) + 1)
      ..sort();
    setState(() {});
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Lottery Number Generator'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(
              'Generated Numbers: ${_lottoNumbers.join(', ')}',
              style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: _generateLottoNumbers,
              child: Text('Generate Numbers'),
            ),
          ],
        ),
      ),
    );
  }
}

The code above generates random lottery numbers and displays them on the screen when the button is clicked.

8. Final Code

Now let’s integrate the code we have written so far to complete the final code:


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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Lottery Number Generator',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: LottoHome(),
    );
  }
}

class LottoHome extends StatefulWidget {
  @override
  _LottoHomeState createState() => _LottoHomeState();
}

class _LottoHomeState extends State {
  List _lottoNumbers = [];

  void _generateLottoNumbers() {
    final Random random = Random();
    _lottoNumbers = List.generate(6, (index) => random.nextInt(45) + 1)
      ..sort();
    setState(() {});
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Lottery Number Generator'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(
              'Generated Numbers: ${_lottoNumbers.join(', ')}',
              style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: _generateLottoNumbers,
              child: Text('Generate Numbers'),
            ),
          ],
        ),
      ),
    );
  }
}

9. Conclusion

In this course, we have step-by-step examined how to complete the user interface (UI) of a lottery app using Flutter. We configured the UI and implemented the functionality to generate lottery numbers when the button is clicked. Through this course, you have learned the basic methods of UI configuration in Flutter and state management.

Feel free to explore adding more complex features or ways to enhance the user experience. Flutter is a very powerful framework that provides the possibility to develop various apps. Thank you!