Conversation with Merlin [email protected] · Wed Dec 27 2023

Can you create me a simple login and register page in flutter and tell me, how do I add a database without any fees?

Certainly! Here's a very basic example of a login and registration UI in Flutter. For the database, you can use Firebase, which offers a generous free tier that you can use for development purposes. Below is the outline of a simple login and registration page, and afterward, I'll provide instructions on how to integrate Firebase.

First, set up your Flutter environment if you haven't already. Then create a new Flutter project and replace the contents of your main.dart file with the following:

main.dart

void main() { (MyApp()); } class MyApp extends StatelessWidget{ @override Widget build(BuildContext){ return MaterialApp( title: 'Flutter Login', theme: ThemeData( primarySwatch: Colors.blue, ), home: LoginScreen(), ); } } class LoginScreen extends StatefulWidget { @ _LoginScreenState createState() => _LoginScreenState(); } class _LoginScreenState extends State<LoginScreen> { final TextEditingController _emailController = TextEditingController(); final TextEditingController _passwordController = TextEditingController(); void _register { // Implement registration logic print('The user wants to register with email ${emailController.text} and password ${_passwordController.text}'); } void _login() { // Implement login logic print('The user wants to login with email ${_emailController.text and password ${_passwordController.text}'); } @ Widget build(BuildContext context){ return Scaffold( appBar: AppBar( title: Text('Login'), ), body: Padding( padding: EdgeInsets.all(16.0), child: Column( mainAxisAlignment: MainAxisAlignment.center, crossAxisAlignment: CrossAxisAlignment.stretch, children: <Widget>[ TextFormField( controller: _emailController, decoration: InputDecoration( labelText: 'Email', ), keyboardType: TextInputType.emailAddress, TextFormField( controller: _passwordController, decoration: InputDecoration( labelText: 'Password', obscureText: true, ), ElevatedButton( : Text('Login'), onPressed: _login, ), TextButton( child: Text('Register'), onPressed _register, ), ], ), ), ); } }

This code will create a simple application with two text fields and buttons for logging in and registering.

Integrating Firebase as a Free Database:

  1. Set up Firebase:

    • Go to Firebase Console.
    • Click 'Add project', and create a new project for your app.
    • Once the project is created, register your app with Firebase by adding an Android or iOS app.
    • For Android, download the google-services.json file and place it in the android/app directory of your Flutter project.
    • iOS, download the GoogleService-Info.plist file use Xcode to incorporate it into your project.
  2. Add Firebase to Your Flutter App:

    • Open Flutter project and add the following Firebase core dependency inside the pubspec.yaml file.
    dependencies: flutter: sdk flutter firebase_core: "^latest_version" ``3. **Initialize Firebase:** - Modify your `main.dart` by adding Firebase initialization inside the `main` function, as shown below:
import 'package:firebase_core/firebase_core.dart'; import 'package:flutter/material.dart'; void main() async { WidgetsFlutterBindingInitialized(); await Firebase.initializeApp(); runApp(MyApp()); } // ... Rest of your Flutter app code
  1. ** Firebase Authentication:**
    • Add the Firebase authentication package to your pubspec.yaml file.
    dependencies: flutter: sdk: flutter firebase_core: "^latest_version" firebase_auth:latest_version"
    • Run flutter pub get to install the new dependency.

5 Implement Authentication Logic:

  • Modify the _register and _login methods in your main.dart file to use Firebase authentication methods for user registration and login. This is a starting point for your implementation. Keep in mind that to add full database capabilities, you'd need to integrate Firebase or Firebase Realtime Database as well by following a similar set of instructions and use the respective FlutterFire plugins.

Remember, while Firebase offers a free, it's important to monitor your usage to make sure you don't exceed the limits that are provided at no cost. For local solutions without an internet connection or for simpler, consider using packages like sqflite (for SQLite) or hive for a local NoSQL database, both which can be suitable for small applications and are free of charge.

now I also want to add a bmi calculator, can you make me a cool looking bmi calculator as well but in another file maybe? for organization purpose

Absolutely, I can guide you through creating a simple yet aesthetically pleasing BMI (Body Mass Index) calculator in Flutter. You'll want to create a new Dart file for this, which I'll call bmi_calculator.dart. Here's a simple version of what it could look like:

bmi_calculator.dart

import 'package:flutter/material.dart'; class BmiCalculatorScreen extends StatefulWidget { @ _BmiCalculatorScreenState createState() => _BmiCalculatorScreenState(); } class _BmiCalculatorScreenState extends State<BmiCalculatorScreen> { final TextEditingController _heightController = TextEditingController(); final TextEditingController _weightController = TextEditingController(); double? _bmiResult; String? _bmiText; void _calculateBMI { double height = double.parse(_heightController.text) / 100; // Convert cm to meters double weight = double.parse(_weightController.text); double bmi = weight / (height * height); setState(() { _bmiResult = bmi; if (bmi < 18.5) { _bmiText = 'Underweight'; } else if (bmi >= 18.5 && bmi < 24.9) { _bmiText = 'Normal weight'; } else if (bmi >= 24.9 && bmi < 29.9) { _bmiText = 'Overweight'; } else { _bmiText = 'Obesity'; } }); } @ Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text('BMI Calculator'), centerTitle: true, backgroundColor: Colors.deepPurple, ), body: Column( mainAxisAlignment: MainAxisAlignment.center, children: [ Padding( padding: EdgeInsets.symmetric(horizontal: 24.0), child: TextField( controller: _heightController, keyboardType: TextInputType.numberWithOptions(decimal: true), decoration: InputDecoration( labelText: 'Height (cm)', icon: Icon(Icons.trending_up, color: Colors.deepPurple), ), ), ), SizedBox(height: 20), Padding( padding: EdgeInsets.symmetric(horizontal: 24.0), child: TextField( controller: _weightController, keyboardType: TextInputType.numberWithOptions(decimal: true), decoration: InputDecoration( labelText: 'Weight (kg)', icon: Icon(Icons.line_weight, color: Colors.deepPurple), ), ), ), SizedBox(height: 40), TextButton( style: TextButton.style, primary: Colors.white, backgroundColor: Colors.deepPurple, padding: EdgeInsets.symmetric(vertical: 10.0, horizontal: 50.0), ), onPressed: _calculateBMI, child: Text( 'Calculate', style: TextStyle(fontSize: 20, color: Colors.white), ), ), if (_bmiResult != null) ...[ Text( 'Your BMI is: ${_bmiResult.toStringAsFixed(1)}', style: TextStyle( fontSize: 24, fontWeight: FontWeight.bold, ), ), Text( '($_bmiText)', style: TextStyle( fontSize: 18, fontStyle: FontStyle.italic, ), ), ], ], ), ); } }

Integration

Now, to use this BMI calculator in your application, you will need to call this screen from your main app. For simplicity, I'm assuming your main app is a typical Flutter application with a Material route setup.

In your main.dart (or wherever your routes are defined), add the following:

import 'bmi_calculator.dart'; // Make sure to import the BMI calculator screen // inside your MaterialApp widget routes: { '/bmi_calculator': (context) => BmiCalculatorScreen(), // ... any other routes },

To navigate to the BMI calculator, you can use:

Navigator.pushNamed(context, '/bmi_calculator');

This BMI calculator takes the user's height in centimeters and weight in kilograms to calculate the BMI. Make sure to do proper validation for the text fields in a production app (i.e., checking for null, empty strings, and valid numbers), and handle parsing errors. I have skipped these for brevity.

Remember to run flutter pub get to fetch the dependencies when you update your pubspec.yaml file, and use appropriate error handling and validation for a robust application. This example is kept simple and understandably lacks those aspects for clarity.