Age Calculator Flutter App (Firebase)

Introduction

In this tutorial, we will learn how to use the Age Calculator Flutter App built using Firebase. The Age Calculator App is a simple and essential tool that allows users to calculate their age based on their birthdate. It's a great example of how to use Firebase with Flutter to build a small but useful application.

Tutorial: Using the Age Calculator Flutter App with Firebase

Step 1: Install the Flutter SDK

To start building the Age Calculator App, you need to install the Flutter SDK. If you haven't done so already, follow the instructions on the Flutter official website to download and install the SDK.

Step 2: Create a Firebase Project

To use Firebase with your Flutter App, you need to create a Firebase project. Follow the instructions on the Firebase official website to create a new project.

Step 3: Set up the Firebase SDK in your Flutter Project

In your Flutter project, add the following dependencies to your pubspec.yaml file:

dependencies:
  flutter:
    sdk: flutter
  firebase_core: "^1.10.0"
  firebase_auth: "^1.3.2"

Then, run the following command to install the dependencies:

flutter pub get

Step 4: Initialize Firebase in your App

In your Flutter project, create a new file called main.dart. In this file, import the Firebase modules and initialize Firebase:

import 'package:firebase_core/firebase_core.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(MyApp());
}

Step 5: Create the Age Calculator Form

Create a new file called age_calculator_form.dart. In this file, create a widget that contains the form:

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

class AgeCalculatorForm extends StatefulWidget {
  @override
  _AgeCalculatorFormState createState() => _AgeCalculatorFormState();
}

class _AgeCalculatorFormState extends State<AgeCalculatorForm> {
  final _formKey = GlobalKey<FormState>();
  DateTime _birthdate = DateTime.now();

  DateTime _dateOfBirthValidator(String value) {
    return DateTime.parse(value);
  }

  void _onSubmit() {
    _formKey.currentState.save();
    final dateOfBirth = _birthdate;
    final now = DateTime.now();
    final age = now.difference(dateOfBirth).inYears;
    // TODO: Display the calculated age
  }

  @override
  Widget build(BuildContext context) {
    return Form(
      key: _formKey,
      child: Column(
        children: <Widget>[
          TextFormField(
            decoration: InputDecoration(labelText: 'Date of Birth'),
            validator: _dateOfBirthValidator,
            onSaved: (String value) {
              setState(() {
                _birthdate = DateTime.parse(value);
              });
            },
            onTap: () {
              showDatePicker(
                context: context,
                initialDate: _birthdate,
                firstDate: DateTime(1900),
                lastDate: DateTime.now(),
              ).then((selectedDate) {
                if (selectedDate!= null) {
                  setState(() {
                    _birthdate = selectedDate;
                  });
                }
              });
            },
          ),
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 16.0),
            child: ElevatedButton(
              onPressed: _onSubmit,
              child: Text('Calculate Age'),
            ),
          ),
        ],
      ),
    );
  }
}

Step 6: Create the Age Calculator App

Create a new file called main.dart. In this file, import the AgeCalculatorForm widget and run the app:

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

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

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

Step 7: Run the App

Run the app on an emulator or a physical device. Open the app and select a date of birth. Click the 'Calculate Age' button to display the calculated age.

That's it! You have now created a Flutter app that uses Firebase to calculate the user's age based on their birthdate.