Flutter Templates
Building an E-commerce App with Flutter, Back4App, and Stripe Integration via Cloud Code

48min
Introduction
Developing an e-commerce app involves multiple components, including product listings, shopping cart functionality, secure payment processing, order tracking, and user reviews. Combining Flutter's powerful UI toolkit with Back4App's scalable backend services simplifies the development process. Additionally, integrating Stripe for payment processing via Back4App Cloud Code allows for secure and professional transaction handling.
In this tutorial, you will build an e-commerce app with the following features:
Product Listings: Display products with images, descriptions, and prices.
Shopping Cart: Add and remove products from the cart.
User Accounts: Manage user profiles and addresses.
Secure Checkout: Process payments securely using Stripe via Back4App Cloud Code.
Order Tracking: Track order status and history.
Reviews and Ratings: Allow users to submit reviews and ratings.
Prerequisites
To follow this tutorial, you will need:
Flutter SDK installed on your machine. Follow the Flutter installation guide.
Basic knowledge of Flutter and Dart.
An IDE or text editor like Visual Studio Code or Android Studio.
A Back4App account. Sign up at Back4App.
Stripe account. Sign up at Stripe to obtain API keys.
Node.js and npm installed for Cloud Code development.
﻿
Step 1 – Setting Up the Flutter Project
1.1. Create a New Flutter Project
Open your terminal and run:
Bash
flutter create ecommerce_app
flutter create ecommerce_app
﻿
Navigate to the project directory:
Bash
cd ecommerce_app
cd ecommerce_app
﻿
1.2. Add Dependencies
Open pubspec.yaml and add the following dependencies:
YAML
dependencies:
  flutter:
    sdk: flutter
  parse_server_sdk_flutter: ^4.0.1
  provider: ^6.0.0
  cached_network_image: ^3.2.0
  flutter_stripe: ^5.2.0
  uuid: ^3.0.6
dependencies:
  flutter:
    sdk: flutter
  parse_server_sdk_flutter: ^4.0.1
  provider: ^6.0.0
  cached_network_image: ^3.2.0
  flutter_stripe: ^5.2.0
  uuid: ^3.0.6
﻿
Run flutter pub get to install the packages.
Note:
parse_server_sdk_flutter for Back4App integration.
provider for state management.
cached_network_image for efficient image loading.
flutter_stripe for Stripe integration on the client side.
uuid for generating unique identifiers.
  
Step 2 – Setting Up Back4App
2.1. Create a New Back4App Application
Log in to your Back4App dashboard.
Click on "Create new App".
Enter "EcommerceApp" as the application name and click "Create".
2.2. Set Up the Data Models
We need to create several classes in Back4App:
Product
User (Built-in class)
Order
OrderItem
Review
2.2.1. Product Class
Navigate to the "Database" section.
Click on "Create a class".
Select "Custom" and enter "Product" as the class name.
Add the following columns:
name: String
description: String
price: Number
image: File
category: String
inventory: Number
2.2.2. Order Class
Create an "Order" class with the following columns:
user: Pointer<_User>
totalAmount: Number
status: String (Values: "pending", "paid", "shipped", "delivered")
paymentIntentId: String (To track Stripe payment)
shippingAddress: String
2.2.3. OrderItem Class
Create an "OrderItem" class with the following columns:
order: Pointer
product: Pointer
quantity: Number
price: Number
2.2.4. Review Class
Create a "Review" class with the following columns:
product: Pointer
user: Pointer<_User>
rating: Number
comment: String
2.3. Obtain Application Credentials
Navigate to App Settings > Security & Keys.
Note down your Application ID and Client Key.
  
Step 3 – Implementing Product Management
3.1. Initializing Parse in Flutter
Open lib/main.dart and modify it:
Dart
import 'package:flutter/material.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import 'package:provider/provider.dart';
import 'screens/home_screen.dart';
import 'services/product_service.dart';

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

  const keyApplicationId = 'YOUR_APPLICATION_ID';
  const keyClientKey = 'YOUR_CLIENT_KEY';
  const keyParseServerUrl = 'https://parseapi.back4app.com';

  await Parse().initialize(
    keyApplicationId,
    keyParseServerUrl,
    clientKey: keyClientKey,
    autoSendSessionId: true,
    debug: true,
  );

  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider<ProductService>(
      create: (_) => ProductService(),
      child: MaterialApp(
        title: 'E-commerce App',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: HomeScreen(),
      ),
    );
  }
}
import 'package:flutter/material.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import 'package:provider/provider.dart';
import 'screens/home_screen.dart';
import 'services/product_service.dart';

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

  const keyApplicationId = 'YOUR_APPLICATION_ID';
  const keyClientKey = 'YOUR_CLIENT_KEY';
  const keyParseServerUrl = 'https://parseapi.back4app.com';

  await Parse().initialize(
    keyApplicationId,
    keyParseServerUrl,
    clientKey: keyClientKey,
    autoSendSessionId: true,
    debug: true,
  );

  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider<ProductService>(
      create: (_) => ProductService(),
      child: MaterialApp(
        title: 'E-commerce App',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: HomeScreen(),
      ),
    );
  }
}
﻿
Replace 'YOUR_APPLICATION_ID' and 'YOUR_CLIENT_KEY' with your Back4App credentials.
3.2. Creating the Product Model
Create a directory models under lib and add product.dart:
Dart
// lib/models/product.dart
class Product {
  String id;
  String name;
  String description;
  double price;
  String imageUrl;
  String category;
  int inventory;

  Product({
    required this.id,
    required this.name,
    required this.description,
    required this.price,
    required this.imageUrl,
    required this.category,
    required this.inventory,
  });
}
// lib/models/product.dart
class Product {
  String id;
  String name;
  String description;
  double price;
  String imageUrl;
  String category;
  int inventory;

  Product({
    required this.id,
    required this.name,
    required this.description,
    required this.price,
    required this.imageUrl,
    required this.category,
    required this.inventory,
  });
}
﻿
3.3. Implementing Product Service
Create a directory services under lib and add product_service.dart:
Dart
// lib/services/product_service.dart
import 'package:flutter/material.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import '../models/product.dart';

class ProductService with ChangeNotifier {
  List<Product> products = [];

  Future<void> fetchProducts() async {
    final query = QueryBuilder<ParseObject>(ParseObject('Product'));

    final response = await query.query();

    if (response.success && response.results != null) {
      products = response.results!.map((data) {
        return Product(
          id: data.objectId!,
          name: data.get<String>('name')!,
          description: data.get<String>('description')!,
          price: data.get<num>('price')!.toDouble(),
          imageUrl: data.get<ParseFileBase>('image')!.url!,
          category: data.get<String>('category')!,
          inventory: data.get<num>('inventory')!.toInt(),
        );
      }).toList();

      notifyListeners();
    }
  }
}
// lib/services/product_service.dart
import 'package:flutter/material.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import '../models/product.dart';

class ProductService with ChangeNotifier {
  List<Product> products = [];

  Future<void> fetchProducts() async {
    final query = QueryBuilder<ParseObject>(ParseObject('Product'));

    final response = await query.query();

    if (response.success && response.results != null) {
      products = response.results!.map((data) {
        return Product(
          id: data.objectId!,
          name: data.get<String>('name')!,
          description: data.get<String>('description')!,
          price: data.get<num>('price')!.toDouble(),
          imageUrl: data.get<ParseFileBase>('image')!.url!,
          category: data.get<String>('category')!,
          inventory: data.get<num>('inventory')!.toInt(),
        );
      }).toList();

      notifyListeners();
    }
  }
}
﻿
3.4. Creating the Home Screen
Create screens directory under lib and add home_screen.dart:
Dart
// lib/screens/home_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/product_service.dart';
import 'product_detail_screen.dart';

class HomeScreen extends StatefulWidget {
  @override
  _HomeScreenState createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  late ProductService _productService;

  @override
  void initState() {
    super.initState();
    _productService = Provider.of<ProductService>(context, listen: false);
    _productService.fetchProducts();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('E-commerce App'),
        actions: [
          IconButton(
            icon: Icon(Icons.shopping_cart),
            onPressed: () {
              // Navigate to cart screen (to be implemented)
            },
          ),
        ],
      ),
      body: Consumer<ProductService>(
        builder: (context, productService, child) {
          if (productService.products.isEmpty) {
            return Center(child: CircularProgressIndicator());
          }

          return GridView.builder(
            padding: EdgeInsets.all(8.0),
            itemCount: productService.products.length,
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
              crossAxisCount: 2,
              childAspectRatio: 0.75,
            ),
            itemBuilder: (context, index) {
              final product = productService.products[index];
              return GestureDetector(
                onTap: () {
                  Navigator.push(
                    context,
                    MaterialPageRoute(
                      builder: (_) => ProductDetailScreen(product: product),
                    ),
                  );
                },
                child: Card(
                  child: Column(
                    children: [
                      Expanded(
                        child: Image.network(
                          product.imageUrl,
                          fit: BoxFit.cover,
                        ),
                      ),
                      Text(product.name),
                      Text('\$${product.price.toStringAsFixed(2)}'),
                    ],
                  ),
                ),
              );
            },
          );
        },
      ),
    );
  }
}
// lib/screens/home_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/product_service.dart';
import 'product_detail_screen.dart';

class HomeScreen extends StatefulWidget {
  @override
  _HomeScreenState createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  late ProductService _productService;

  @override
  void initState() {
    super.initState();
    _productService = Provider.of<ProductService>(context, listen: false);
    _productService.fetchProducts();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('E-commerce App'),
        actions: [
          IconButton(
            icon: Icon(Icons.shopping_cart),
            onPressed: () {
              // Navigate to cart screen (to be implemented)
            },
          ),
        ],
      ),
      body: Consumer<ProductService>(
        builder: (context, productService, child) {
          if (productService.products.isEmpty) {
            return Center(child: CircularProgressIndicator());
          }

          return GridView.builder(
            padding: EdgeInsets.all(8.0),
            itemCount: productService.products.length,
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
              crossAxisCount: 2,
              childAspectRatio: 0.75,
            ),
            itemBuilder: (context, index) {
              final product = productService.products[index];
              return GestureDetector(
                onTap: () {
                  Navigator.push(
                    context,
                    MaterialPageRoute(
                      builder: (_) => ProductDetailScreen(product: product),
                    ),
                  );
                },
                child: Card(
                  child: Column(
                    children: [
                      Expanded(
                        child: Image.network(
                          product.imageUrl,
                          fit: BoxFit.cover,
                        ),
                      ),
                      Text(product.name),
                      Text('\$${product.price.toStringAsFixed(2)}'),
                    ],
                  ),
                ),
              );
            },
          );
        },
      ),
    );
  }
}
﻿
3.5. Product Detail Screen
Create product_detail_screen.dart under lib/screens/:
Dart
// lib/screens/product_detail_screen.dart
import 'package:flutter/material.dart';
import '../models/product.dart';
import '../services/cart_service.dart';
import 'package:provider/provider.dart';

class ProductDetailScreen extends StatelessWidget {
  final Product product;

  ProductDetailScreen({required this.product});

  @override
  Widget build(BuildContext context) {
    final cartService = Provider.of<CartService>(context);

    return Scaffold(
      appBar: AppBar(title: Text(product.name)),
      body: Column(
        children: [
          Expanded(child: Image.network(product.imageUrl)),
          Padding(
            padding: const EdgeInsets.all(16.0),
            child: Text(product.description),
          ),
          Text('\$${product.price.toStringAsFixed(2)}'),
          ElevatedButton(
            onPressed: () {
              cartService.addToCart(product);
              ScaffoldMessenger.of(context).showSnackBar(
                SnackBar(content: Text('Added to cart')),
              );
            },
            child: Text('Add to Cart'),
          ),
        ],
      ),
    );
  }
}
// lib/screens/product_detail_screen.dart
import 'package:flutter/material.dart';
import '../models/product.dart';
import '../services/cart_service.dart';
import 'package:provider/provider.dart';

class ProductDetailScreen extends StatelessWidget {
  final Product product;

  ProductDetailScreen({required this.product});

  @override
  Widget build(BuildContext context) {
    final cartService = Provider.of<CartService>(context);

    return Scaffold(
      appBar: AppBar(title: Text(product.name)),
      body: Column(
        children: [
          Expanded(child: Image.network(product.imageUrl)),
          Padding(
            padding: const EdgeInsets.all(16.0),
            child: Text(product.description),
          ),
          Text('\$${product.price.toStringAsFixed(2)}'),
          ElevatedButton(
            onPressed: () {
              cartService.addToCart(product);
              ScaffoldMessenger.of(context).showSnackBar(
                SnackBar(content: Text('Added to cart')),
              );
            },
            child: Text('Add to Cart'),
          ),
        ],
      ),
    );
  }
}
﻿
  
Step 4 – Implementing User Accounts
4.1. Authentication Service
Add auth_service.dart under lib/services/:
Dart
// lib/services/auth_service.dart
import 'package:flutter/material.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';

class AuthService with ChangeNotifier {
  ParseUser? user;

  Future<bool> signUp(String username, String password, String email) async {
    user = ParseUser.createUser(username, password, email);
    final response = await user!.signUp();

    if (response.success) {
      notifyListeners();
      return true;
    } else {
      user = null;
      return false;
    }
  }

  Future<bool> login(String username, String password) async {
    user = ParseUser(username, password, null);
    final response = await user!.login();

    if (response.success) {
      notifyListeners();
      return true;
    } else {
      user = null;
      return false;
    }
  }

  Future<void> logout() async {
    if (user != null) {
      await user!.logout();
      user = null;
      notifyListeners();
    }
  }

  bool get isAuthenticated => user != null;
}
// lib/services/auth_service.dart
import 'package:flutter/material.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';

class AuthService with ChangeNotifier {
  ParseUser? user;

  Future<bool> signUp(String username, String password, String email) async {
    user = ParseUser.createUser(username, password, email);
    final response = await user!.signUp();

    if (response.success) {
      notifyListeners();
      return true;
    } else {
      user = null;
      return false;
    }
  }

  Future<bool> login(String username, String password) async {
    user = ParseUser(username, password, null);
    final response = await user!.login();

    if (response.success) {
      notifyListeners();
      return true;
    } else {
      user = null;
      return false;
    }
  }

  Future<void> logout() async {
    if (user != null) {
      await user!.logout();
      user = null;
      notifyListeners();
    }
  }

  bool get isAuthenticated => user != null;
}
﻿
4.2. Authentication Screens
Create login_screen.dart and signup_screen.dart under lib/screens/.
Login Screen:
Dart
// lib/screens/login_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/auth_service.dart';
import 'home_screen.dart';
import 'signup_screen.dart';

class LoginScreen extends StatelessWidget {
  final TextEditingController _usernameController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();

  void _login(BuildContext context) async {
    final authService = Provider.of<AuthService>(context, listen: false);
    bool success = await authService.login(
      _usernameController.text.trim(),
      _passwordController.text.trim(),
    );

    if (success) {
      Navigator.pushReplacement(
        context,
        MaterialPageRoute(builder: (_) => HomeScreen()),
      );
    } else {
      ScaffoldMessenger.of(context)
          .showSnackBar(SnackBar(content: Text('Login failed')));
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('E-commerce App Login'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          children: [
            TextField(
              controller: _usernameController,
              decoration: InputDecoration(labelText: 'Username or Email'),
            ),
            TextField(
              controller: _passwordController,
              decoration: InputDecoration(labelText: 'Password'),
              obscureText: true,
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () => _login(context),
              child: Text('Login'),
            ),
            TextButton(
              onPressed: () {
                Navigator.push(
                  context,
                  MaterialPageRoute(builder: (_) => SignupScreen()),
                );
              },
              child: Text('Don\'t have an account? Sign up'),
            )
          ],
        ),
      ),
    );
  }
}
// lib/screens/login_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/auth_service.dart';
import 'home_screen.dart';
import 'signup_screen.dart';

class LoginScreen extends StatelessWidget {
  final TextEditingController _usernameController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();

  void _login(BuildContext context) async {
    final authService = Provider.of<AuthService>(context, listen: false);
    bool success = await authService.login(
      _usernameController.text.trim(),
      _passwordController.text.trim(),
    );

    if (success) {
      Navigator.pushReplacement(
        context,
        MaterialPageRoute(builder: (_) => HomeScreen()),
      );
    } else {
      ScaffoldMessenger.of(context)
          .showSnackBar(SnackBar(content: Text('Login failed')));
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('E-commerce App Login'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          children: [
            TextField(
              controller: _usernameController,
              decoration: InputDecoration(labelText: 'Username or Email'),
            ),
            TextField(
              controller: _passwordController,
              decoration: InputDecoration(labelText: 'Password'),
              obscureText: true,
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () => _login(context),
              child: Text('Login'),
            ),
            TextButton(
              onPressed: () {
                Navigator.push(
                  context,
                  MaterialPageRoute(builder: (_) => SignupScreen()),
                );
              },
              child: Text('Don\'t have an account? Sign up'),
            )
          ],
        ),
      ),
    );
  }
}
﻿
Signup Screen:
Dart
// lib/screens/signup_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/auth_service.dart';
import 'home_screen.dart';

class SignupScreen extends StatelessWidget {
  final TextEditingController _usernameController = TextEditingController();
  final TextEditingController _emailController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();

  void _signUp(BuildContext context) async {
    final authService = Provider.of<AuthService>(context, listen: false);
    bool success = await authService.signUp(
      _usernameController.text.trim(),
      _passwordController.text.trim(),
      _emailController.text.trim(),
    );

    if (success) {
      Navigator.pushReplacement(
        context,
        MaterialPageRoute(builder: (_) => HomeScreen()),
      );
    } else {
      ScaffoldMessenger.of(context)
          .showSnackBar(SnackBar(content: Text('Signup failed')));
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('E-commerce App Signup'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          children: [
            TextField(
              controller: _usernameController,
              decoration: InputDecoration(labelText: 'Username'),
            ),
            TextField(
              controller: _emailController,
              decoration: InputDecoration(labelText: 'Email'),
            ),
            TextField(
              controller: _passwordController,
              decoration: InputDecoration(labelText: 'Password'),
              obscureText: true,
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () => _signUp(context),
              child: Text('Sign Up'),
            ),
          ],
        ),
      ),
    );
  }
}
// lib/screens/signup_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/auth_service.dart';
import 'home_screen.dart';

class SignupScreen extends StatelessWidget {
  final TextEditingController _usernameController = TextEditingController();
  final TextEditingController _emailController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();

  void _signUp(BuildContext context) async {
    final authService = Provider.of<AuthService>(context, listen: false);
    bool success = await authService.signUp(
      _usernameController.text.trim(),
      _passwordController.text.trim(),
      _emailController.text.trim(),
    );

    if (success) {
      Navigator.pushReplacement(
        context,
        MaterialPageRoute(builder: (_) => HomeScreen()),
      );
    } else {
      ScaffoldMessenger.of(context)
          .showSnackBar(SnackBar(content: Text('Signup failed')));
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('E-commerce App Signup'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          children: [
            TextField(
              controller: _usernameController,
              decoration: InputDecoration(labelText: 'Username'),
            ),
            TextField(
              controller: _emailController,
              decoration: InputDecoration(labelText: 'Email'),
            ),
            TextField(
              controller: _passwordController,
              decoration: InputDecoration(labelText: 'Password'),
              obscureText: true,
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () => _signUp(context),
              child: Text('Sign Up'),
            ),
          ],
        ),
      ),
    );
  }
}
﻿
4.3. Update Main to Include AuthService
In main.dart, wrap the MaterialApp with MultiProvider:
Dart
// In main.dart
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        ChangeNotifierProvider<ProductService>(
          create: (_) => ProductService(),
        ),
        ChangeNotifierProvider<AuthService>(
          create: (_) => AuthService(),
        ),
        ChangeNotifierProvider<CartService>(
          create: (_) => CartService(),
        ),
      ],
      child: MaterialApp(
        // ...
      ),
    );
  }
}
// In main.dart
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        ChangeNotifierProvider<ProductService>(
          create: (_) => ProductService(),
        ),
        ChangeNotifierProvider<AuthService>(
          create: (_) => AuthService(),
        ),
        ChangeNotifierProvider<CartService>(
          create: (_) => CartService(),
        ),
      ],
      child: MaterialApp(
        // ...
      ),
    );
  }
}
﻿
4.4. Redirect Based on Authentication State
Modify main.dart to check authentication status:
Dart
// main.dart
// Inside the build method
home: Consumer<AuthService>(
  builder: (context, authService, child) {
    if (authService.isAuthenticated) {
      return HomeScreen();
    } else {
      return LoginScreen();
    }
  },
),
// main.dart
// Inside the build method
home: Consumer<AuthService>(
  builder: (context, authService, child) {
    if (authService.isAuthenticated) {
      return HomeScreen();
    } else {
      return LoginScreen();
    }
  },
),
﻿
  
Step 5 – Shopping Cart Functionality
5.1. Create Cart Service
Add cart_service.dart under lib/services/:
Dart
// lib/services/cart_service.dart
import 'package:flutter/material.dart';
import '../models/product.dart';

class CartItem {
  final Product product;
  int quantity;

  CartItem({required this.product, this.quantity = 1});
}

class CartService with ChangeNotifier {
  Map<String, CartItem> _items = {};

  void addToCart(Product product) {
    if (_items.containsKey(product.id)) {
      _items[product.id]!.quantity++;
    } else {
      _items[product.id] = CartItem(product: product);
    }
    notifyListeners();
  }

  void removeFromCart(String productId) {
    _items.remove(productId);
    notifyListeners();
  }

  void clearCart() {
    _items.clear();
    notifyListeners();
  }

  Map<String, CartItem> get items => _items;

  double get totalAmount {
    double total = 0.0;
    _items.forEach((key, cartItem) {
      total += cartItem.product.price * cartItem.quantity;
    });
    return total;
  }
}
// lib/services/cart_service.dart
import 'package:flutter/material.dart';
import '../models/product.dart';

class CartItem {
  final Product product;
  int quantity;

  CartItem({required this.product, this.quantity = 1});
}

class CartService with ChangeNotifier {
  Map<String, CartItem> _items = {};

  void addToCart(Product product) {
    if (_items.containsKey(product.id)) {
      _items[product.id]!.quantity++;
    } else {
      _items[product.id] = CartItem(product: product);
    }
    notifyListeners();
  }

  void removeFromCart(String productId) {
    _items.remove(productId);
    notifyListeners();
  }

  void clearCart() {
    _items.clear();
    notifyListeners();
  }

  Map<String, CartItem> get items => _items;

  double get totalAmount {
    double total = 0.0;
    _items.forEach((key, cartItem) {
      total += cartItem.product.price * cartItem.quantity;
    });
    return total;
  }
}
﻿
5.2. Create Cart Screen
Add cart_screen.dart under lib/screens/:
Dart
// lib/screens/cart_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/cart_service.dart';
import 'checkout_screen.dart';

class CartScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final cartService = Provider.of<CartService>(context);
    final cartItems = cartService.items.values.toList();

    return Scaffold(
      appBar: AppBar(title: Text('Your Cart')),
      body: Column(
        children: [
          Expanded(
            child: ListView.builder(
              itemCount: cartService.items.length,
              itemBuilder: (context, index) {
                final cartItem = cartItems[index];
                return ListTile(
                  leading: Image.network(cartItem.product.imageUrl),
                  title: Text(cartItem.product.name),
                  subtitle: Text('Quantity: ${cartItem.quantity}'),
                  trailing: Text('\$${(cartItem.product.price * cartItem.quantity).toStringAsFixed(2)}'),
                );
              },
            ),
          ),
          Text('Total: \$${cartService.totalAmount.toStringAsFixed(2)}'),
          ElevatedButton(
            onPressed: () {
              Navigator.push(
                context,
                MaterialPageRoute(builder: (_) => CheckoutScreen()),
              );
            },
            child: Text('Proceed to Checkout'),
          ),
        ],
      ),
    );
  }
}
// lib/screens/cart_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/cart_service.dart';
import 'checkout_screen.dart';

class CartScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final cartService = Provider.of<CartService>(context);
    final cartItems = cartService.items.values.toList();

    return Scaffold(
      appBar: AppBar(title: Text('Your Cart')),
      body: Column(
        children: [
          Expanded(
            child: ListView.builder(
              itemCount: cartService.items.length,
              itemBuilder: (context, index) {
                final cartItem = cartItems[index];
                return ListTile(
                  leading: Image.network(cartItem.product.imageUrl),
                  title: Text(cartItem.product.name),
                  subtitle: Text('Quantity: ${cartItem.quantity}'),
                  trailing: Text('\$${(cartItem.product.price * cartItem.quantity).toStringAsFixed(2)}'),
                );
              },
            ),
          ),
          Text('Total: \$${cartService.totalAmount.toStringAsFixed(2)}'),
          ElevatedButton(
            onPressed: () {
              Navigator.push(
                context,
                MaterialPageRoute(builder: (_) => CheckoutScreen()),
              );
            },
            child: Text('Proceed to Checkout'),
          ),
        ],
      ),
    );
  }
}
﻿
  
Step 6 – Secure Checkout with Stripe Integration via Cloud Code
6.1. Set Up Stripe Account
Sign up for a Stripe account.
Obtain your Publishable Key and Secret Key from the Stripe Dashboard under Developers > API keys.
6.2. Install Stripe SDK in Cloud Code
Back4App supports Cloud Code functions written in JavaScript. We'll write Cloud Code functions to handle payment processing.
6.2.1. Create Cloud Code Project
In your Back4App app dashboard, go to App Settings > Cloud Code Functions.
Click "Edit code" to open the Cloud Code editor.
6.2.2. Initialize npm and Install Stripe Package
In the Cloud Code terminal (provided in the editor), run:
Bash
npm init -y
npm install [email protected]
npm init -y
npm install stripe@8.174.0
﻿
Note: Back4App's Cloud Code uses Node.js version 14.x, so ensure compatibility.
6.3. Create Cloud Function for Payment Intent
Create or modify main.js in the Cloud Code editor:
JS
// main.js
const Stripe = require('stripe');
const stripe = Stripe('YOUR_STRIPE_SECRET_KEY');

Parse.Cloud.define('createPaymentIntent', async (request) => {
  const { amount, currency } = request.params;

  try {
    const paymentIntent = await stripe.paymentIntents.create({
      amount: amount,
      currency: currency,
    });

    return { clientSecret: paymentIntent.client_secret };
  } catch (error) {
    throw new Parse.Error(500, error.message);
  }
});
// main.js
const Stripe = require('stripe');
const stripe = Stripe('YOUR_STRIPE_SECRET_KEY');

Parse.Cloud.define('createPaymentIntent', async (request) => {
  const { amount, currency } = request.params;

  try {
    const paymentIntent = await stripe.paymentIntents.create({
      amount: amount,
      currency: currency,
    });

    return { clientSecret: paymentIntent.client_secret };
  } catch (error) {
    throw new Parse.Error(500, error.message);
  }
});
﻿
Replace 'YOUR_STRIPE_SECRET_KEY' with your actual Stripe secret key.
Security Note: Never expose your secret key on the client side. Keep it secure in Cloud Code.
6.4. Deploy Cloud Code
Click "Deploy" in the Cloud Code editor to deploy your functions.
6.5. Implement Payment in Flutter
6.5.1. Initialize Stripe in Flutter
In main.dart, after Parse().initialize, add:
Dart
import 'package:flutter_stripe/flutter_stripe.dart';

// Inside main() async
Stripe.publishableKey = 'YOUR_STRIPE_PUBLISHABLE_KEY';
import 'package:flutter_stripe/flutter_stripe.dart';

// Inside main() async
Stripe.publishableKey = 'YOUR_STRIPE_PUBLISHABLE_KEY';
﻿
Replace 'YOUR_STRIPE_PUBLISHABLE_KEY' with your Stripe publishable key.
6.5.2. Create Checkout Screen
Add checkout_screen.dart under lib/screens/:
Dart
// lib/screens/checkout_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/cart_service.dart';
import 'package:flutter_stripe/flutter_stripe.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import 'order_confirmation_screen.dart';

class CheckoutScreen extends StatelessWidget {
  Future<void> _processPayment(BuildContext context) async {
    final cartService = Provider.of<CartService>(context, listen: false);
    final totalAmount = (cartService.totalAmount * 100).toInt(); // Amount in cents

    // Call Cloud Function to create Payment Intent
    final response = await ParseCloudFunction('createPaymentIntent').execute(
      parameters: {
        'amount': totalAmount,
        'currency': 'usd',
      },
    );

    if (response.success) {
      final clientSecret = response.result['clientSecret'];

      // Initialize payment sheet
      await Stripe.instance.initPaymentSheet(
        paymentSheetParameters: SetupPaymentSheetParameters(
          paymentIntentClientSecret: clientSecret,
          merchantDisplayName: 'Your E-commerce App',
        ),
      );

      // Display payment sheet
      await Stripe.instance.presentPaymentSheet();

      // Payment successful
      // Save order to Back4App (to be implemented)
      cartService.clearCart();
      Navigator.pushReplacement(
        context,
        MaterialPageRoute(builder: (_) => OrderConfirmationScreen()),
      );
    } else {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Payment failed: ${response.error!.message}')),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    final cartService = Provider.of<CartService>(context);

    return Scaffold(
      appBar: AppBar(title: Text('Checkout')),
      body: Column(
        children: [
          Text('Total: \$${cartService.totalAmount.toStringAsFixed(2)}'),
          ElevatedButton(
            onPressed: () => _processPayment(context),
            child: Text('Pay Now'),
          ),
        ],
      ),
    );
  }
}
// lib/screens/checkout_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/cart_service.dart';
import 'package:flutter_stripe/flutter_stripe.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import 'order_confirmation_screen.dart';

class CheckoutScreen extends StatelessWidget {
  Future<void> _processPayment(BuildContext context) async {
    final cartService = Provider.of<CartService>(context, listen: false);
    final totalAmount = (cartService.totalAmount * 100).toInt(); // Amount in cents

    // Call Cloud Function to create Payment Intent
    final response = await ParseCloudFunction('createPaymentIntent').execute(
      parameters: {
        'amount': totalAmount,
        'currency': 'usd',
      },
    );

    if (response.success) {
      final clientSecret = response.result['clientSecret'];

      // Initialize payment sheet
      await Stripe.instance.initPaymentSheet(
        paymentSheetParameters: SetupPaymentSheetParameters(
          paymentIntentClientSecret: clientSecret,
          merchantDisplayName: 'Your E-commerce App',
        ),
      );

      // Display payment sheet
      await Stripe.instance.presentPaymentSheet();

      // Payment successful
      // Save order to Back4App (to be implemented)
      cartService.clearCart();
      Navigator.pushReplacement(
        context,
        MaterialPageRoute(builder: (_) => OrderConfirmationScreen()),
      );
    } else {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Payment failed: ${response.error!.message}')),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    final cartService = Provider.of<CartService>(context);

    return Scaffold(
      appBar: AppBar(title: Text('Checkout')),
      body: Column(
        children: [
          Text('Total: \$${cartService.totalAmount.toStringAsFixed(2)}'),
          ElevatedButton(
            onPressed: () => _processPayment(context),
            child: Text('Pay Now'),
          ),
        ],
      ),
    );
  }
}
﻿
6.5.3. Handle Payment Confirmation
Create order_confirmation_screen.dart under lib/screens/:
Dart
// lib/screens/order_confirmation_screen.dart
import 'package:flutter/material.dart';

class OrderConfirmationScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Order Confirmed'),
        automaticallyImplyLeading: false,
      ),
      body: Center(
        child: Text('Thank you for your purchase!'),
      ),
    );
  }
}
// lib/screens/order_confirmation_screen.dart
import 'package:flutter/material.dart';

class OrderConfirmationScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Order Confirmed'),
        automaticallyImplyLeading: false,
      ),
      body: Center(
        child: Text('Thank you for your purchase!'),
      ),
    );
  }
}
﻿
6.6. Saving Order to Back4App
Modify the _processPayment method to save the order details:
Dart
// After successful payment
final authService = Provider.of<AuthService>(context, listen: false);
final user = authService.user!;

// Create Order object
final order = ParseObject('Order')
  ..set('user', user)
  ..set('totalAmount', cartService.totalAmount)
  ..set('status', 'paid')
  ..set('paymentIntentId', clientSecret);

// Save Order
final orderResponse = await order.save();

if (orderResponse.success) {
  final orderObject = orderResponse.result;

  // Save OrderItems
  for (var cartItem in cartService.items.values) {
    final orderItem = ParseObject('OrderItem')
      ..set('order', orderObject)
      ..set('product', ParseObject('Product')..objectId = cartItem.product.id)
      ..set('quantity', cartItem.quantity)
      ..set('price', cartItem.product.price);

    await orderItem.save();
  }

  // Clear cart and navigate
  cartService.clearCart();
  Navigator.pushReplacement(
    context,
    MaterialPageRoute(builder: (_) => OrderConfirmationScreen()),
  );
} else {
  ScaffoldMessenger.of(context).showSnackBar(
    SnackBar(content: Text('Failed to save order')),
  );
}
// After successful payment
final authService = Provider.of<AuthService>(context, listen: false);
final user = authService.user!;

// Create Order object
final order = ParseObject('Order')
  ..set('user', user)
  ..set('totalAmount', cartService.totalAmount)
  ..set('status', 'paid')
  ..set('paymentIntentId', clientSecret);

// Save Order
final orderResponse = await order.save();

if (orderResponse.success) {
  final orderObject = orderResponse.result;

  // Save OrderItems
  for (var cartItem in cartService.items.values) {
    final orderItem = ParseObject('OrderItem')
      ..set('order', orderObject)
      ..set('product', ParseObject('Product')..objectId = cartItem.product.id)
      ..set('quantity', cartItem.quantity)
      ..set('price', cartItem.product.price);

    await orderItem.save();
  }

  // Clear cart and navigate
  cartService.clearCart();
  Navigator.pushReplacement(
    context,
    MaterialPageRoute(builder: (_) => OrderConfirmationScreen()),
  );
} else {
  ScaffoldMessenger.of(context).showSnackBar(
    SnackBar(content: Text('Failed to save order')),
  );
}
﻿
  
Step 7 – Order Tracking
7.1. Create Order Service
Add order_service.dart under lib/services/:
Dart
// lib/services/order_service.dart
import 'package:flutter/material.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import '../models/order.dart';

class OrderService with ChangeNotifier {
  List<Order> orders = [];

  Future<void> fetchOrders(ParseUser user) async {
    final query = QueryBuilder<ParseObject>(ParseObject('Order'))
      ..whereEqualTo('user', user)
      ..orderByDescending('createdAt');

    final response = await query.query();

    if (response.success && response.results != null) {
      orders = response.results!.map((data) {
        return Order.fromParseObject(data);
      }).toList();

      notifyListeners();
    }
  }
}
// lib/services/order_service.dart
import 'package:flutter/material.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import '../models/order.dart';

class OrderService with ChangeNotifier {
  List<Order> orders = [];

  Future<void> fetchOrders(ParseUser user) async {
    final query = QueryBuilder<ParseObject>(ParseObject('Order'))
      ..whereEqualTo('user', user)
      ..orderByDescending('createdAt');

    final response = await query.query();

    if (response.success && response.results != null) {
      orders = response.results!.map((data) {
        return Order.fromParseObject(data);
      }).toList();

      notifyListeners();
    }
  }
}
﻿
7.2. Create Order Model
Add order.dart under lib/models/:
Dart
// lib/models/order.dart
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';

class Order {
  String id;
  double totalAmount;
  String status;
  DateTime createdAt;

  Order({
    required this.id,
    required this.totalAmount,
    required this.status,
    required this.createdAt,
  });

  factory Order.fromParseObject(ParseObject object) {
    return Order(
      id: object.objectId!,
      totalAmount: object.get<num>('totalAmount')!.toDouble(),
      status: object.get<String>('status')!,
      createdAt: object.createdAt!,
    );
  }
}
// lib/models/order.dart
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';

class Order {
  String id;
  double totalAmount;
  String status;
  DateTime createdAt;

  Order({
    required this.id,
    required this.totalAmount,
    required this.status,
    required this.createdAt,
  });

  factory Order.fromParseObject(ParseObject object) {
    return Order(
      id: object.objectId!,
      totalAmount: object.get<num>('totalAmount')!.toDouble(),
      status: object.get<String>('status')!,
      createdAt: object.createdAt!,
    );
  }
}
﻿
7.3. Create Orders Screen
Add orders_screen.dart under lib/screens/:
Dart
// lib/screens/orders_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/order_service.dart';
import '../services/auth_service.dart';
import '../models/order.dart';

class OrdersScreen extends StatefulWidget {
  @override
  _OrdersScreenState createState() => _OrdersScreenState();
}

class _OrdersScreenState extends State<OrdersScreen> {
  late OrderService _orderService;

  @override
  void initState() {
    super.initState();
    _orderService = Provider.of<OrderService>(context, listen: false);
    final authService = Provider.of<AuthService>(context, listen: false);
    _orderService.fetchOrders(authService.user!);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Your Orders')),
      body: Consumer<OrderService>(
        builder: (context, orderService, child) {
          if (orderService.orders.isEmpty) {
            return Center(child: Text('No orders found.'));
          }

          return ListView.builder(
            itemCount: orderService.orders.length,
            itemBuilder: (context, index) {
              final order = orderService.orders[index];
              return ListTile(
                title: Text('Order #${order.id}'),
                subtitle: Text('Status: ${order.status}'),
                trailing: Text('\$${order.totalAmount.toStringAsFixed(2)}'),
              );
            },
          );
        },
      ),
    );
  }
}
// lib/screens/orders_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/order_service.dart';
import '../services/auth_service.dart';
import '../models/order.dart';

class OrdersScreen extends StatefulWidget {
  @override
  _OrdersScreenState createState() => _OrdersScreenState();
}

class _OrdersScreenState extends State<OrdersScreen> {
  late OrderService _orderService;

  @override
  void initState() {
    super.initState();
    _orderService = Provider.of<OrderService>(context, listen: false);
    final authService = Provider.of<AuthService>(context, listen: false);
    _orderService.fetchOrders(authService.user!);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Your Orders')),
      body: Consumer<OrderService>(
        builder: (context, orderService, child) {
          if (orderService.orders.isEmpty) {
            return Center(child: Text('No orders found.'));
          }

          return ListView.builder(
            itemCount: orderService.orders.length,
            itemBuilder: (context, index) {
              final order = orderService.orders[index];
              return ListTile(
                title: Text('Order #${order.id}'),
                subtitle: Text('Status: ${order.status}'),
                trailing: Text('\$${order.totalAmount.toStringAsFixed(2)}'),
              );
            },
          );
        },
      ),
    );
  }
}
﻿
  
Step 8 – Reviews and Ratings
8.1. Create Review Service
Add review_service.dart under lib/services/:
Dart
// lib/services/review_service.dart
import 'package:flutter/material.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import '../models/review.dart';

class ReviewService with ChangeNotifier {
  List<Review> reviews = [];

  Future<void> fetchReviews(String productId) async {
    final query = QueryBuilder<ParseObject>(ParseObject('Review'))
      ..whereEqualTo('product', ParseObject('Product')..objectId = productId)
      ..includeObject(['user']);

    final response = await query.query();

    if (response.success && response.results != null) {
      reviews = response.results!.map((data) {
        return Review.fromParseObject(data);
      }).toList();

      notifyListeners();
    }
  }

  Future<void> submitReview(String productId, ParseUser user, int rating, String comment) async {
    final review = ParseObject('Review')
      ..set('product', ParseObject('Product')..objectId = productId)
      ..set('user', user)
      ..set('rating', rating)
      ..set('comment', comment);

    await review.save();
    await fetchReviews(productId);
  }
}
// lib/services/review_service.dart
import 'package:flutter/material.dart';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import '../models/review.dart';

class ReviewService with ChangeNotifier {
  List<Review> reviews = [];

  Future<void> fetchReviews(String productId) async {
    final query = QueryBuilder<ParseObject>(ParseObject('Review'))
      ..whereEqualTo('product', ParseObject('Product')..objectId = productId)
      ..includeObject(['user']);

    final response = await query.query();

    if (response.success && response.results != null) {
      reviews = response.results!.map((data) {
        return Review.fromParseObject(data);
      }).toList();

      notifyListeners();
    }
  }

  Future<void> submitReview(String productId, ParseUser user, int rating, String comment) async {
    final review = ParseObject('Review')
      ..set('product', ParseObject('Product')..objectId = productId)
      ..set('user', user)
      ..set('rating', rating)
      ..set('comment', comment);

    await review.save();
    await fetchReviews(productId);
  }
}
﻿
8.2. Create Review Model
Add review.dart under lib/models/:
Dart
// lib/models/review.dart
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';

class Review {
  String id;
  int rating;
  String comment;
  ParseUser user;

  Review({
    required this.id,
    required this.rating,
    required this.comment,
    required this.user,
  });

  factory Review.fromParseObject(ParseObject object) {
    return Review(
      id: object.objectId!,
      rating: object.get<num>('rating')!.toInt(),
      comment: object.get<String>('comment')!,
      user: object.get<ParseUser>('user')!,
    );
  }
}
// lib/models/review.dart
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';

class Review {
  String id;
  int rating;
  String comment;
  ParseUser user;

  Review({
    required this.id,
    required this.rating,
    required this.comment,
    required this.user,
  });

  factory Review.fromParseObject(ParseObject object) {
    return Review(
      id: object.objectId!,
      rating: object.get<num>('rating')!.toInt(),
      comment: object.get<String>('comment')!,
      user: object.get<ParseUser>('user')!,
    );
  }
}
﻿
8.3. Update Product Detail Screen
In product_detail_screen.dart, add a section to display and submit reviews.
Dart
// At the end of the Column in ProductDetailScreen
Expanded(
  child: Column(
    children: [
      // Display reviews
      Expanded(
        child: Consumer<ReviewService>(
          builder: (context, reviewService, child) {
            if (reviewService.reviews.isEmpty) {
              return Center(child: Text('No reviews yet.'));
            }

            return ListView.builder(
              itemCount: reviewService.reviews.length,
              itemBuilder: (context, index) {
                final review = reviewService.reviews[index];
                return ListTile(
                  title: Text(review.user.username ?? 'Anonymous'),
                  subtitle: Text(review.comment),
                  trailing: Text('${review.rating}/5'),
                );
              },
            );
          },
        ),
      ),
      // Submit review
      TextField(
        controller: _reviewController,
        decoration: InputDecoration(hintText: 'Write a review'),
      ),
      Row(
        children: [
          Text('Rating:'),
          DropdownButton<int>(
            value: _rating,
            onChanged: (value) {
              setState(() {
                _rating = value!;
              });
            },
            items: List.generate(5, (index) => index + 1)
                .map((e) => DropdownMenuItem(value: e, child: Text('$e')))
                .toList(),
          ),
          ElevatedButton(
            onPressed: () {
              final authService = Provider.of<AuthService>(context, listen: false);
              _reviewService.submitReview(
                product.id,
                authService.user!,
                _rating,
                _reviewController.text.trim(),
              );
              _reviewController.clear();
            },
            child: Text('Submit'),
          ),
        ],
      ),
    ],
  ),
),
// At the end of the Column in ProductDetailScreen
Expanded(
  child: Column(
    children: [
      // Display reviews
      Expanded(
        child: Consumer<ReviewService>(
          builder: (context, reviewService, child) {
            if (reviewService.reviews.isEmpty) {
              return Center(child: Text('No reviews yet.'));
            }

            return ListView.builder(
              itemCount: reviewService.reviews.length,
              itemBuilder: (context, index) {
                final review = reviewService.reviews[index];
                return ListTile(
                  title: Text(review.user.username ?? 'Anonymous'),
                  subtitle: Text(review.comment),
                  trailing: Text('${review.rating}/5'),
                );
              },
            );
          },
        ),
      ),
      // Submit review
      TextField(
        controller: _reviewController,
        decoration: InputDecoration(hintText: 'Write a review'),
      ),
      Row(
        children: [
          Text('Rating:'),
          DropdownButton<int>(
            value: _rating,
            onChanged: (value) {
              setState(() {
                _rating = value!;
              });
            },
            items: List.generate(5, (index) => index + 1)
                .map((e) => DropdownMenuItem(value: e, child: Text('$e')))
                .toList(),
          ),
          ElevatedButton(
            onPressed: () {
              final authService = Provider.of<AuthService>(context, listen: false);
              _reviewService.submitReview(
                product.id,
                authService.user!,
                _rating,
                _reviewController.text.trim(),
              );
              _reviewController.clear();
            },
            child: Text('Submit'),
          ),
        ],
      ),
    ],
  ),
),
﻿
  
Conclusion
In this comprehensive tutorial, you've built an e-commerce app using Flutter and Back4App, integrated with Stripe for secure payment processing via Cloud Code. You implemented key features such as product listings, shopping cart functionality, user authentication, order tracking, and reviews.
Key Takeaways
Back4App Integration: Simplifies backend management for your Flutter app.
Stripe Integration via Cloud Code: Securely processes payments without exposing sensitive keys.
Modular Architecture: Separating services and models improves maintainability.
Next Steps
Enhance Security: Implement proper error handling and input validation.
UI/UX Improvements: Refine the user interface for better user experience.
Inventory Management: Update product inventory upon purchase.
Email Notifications: Send order confirmation emails to users.
Admin Panel: Create an admin interface for managing products and orders.
Additional Resources
﻿Back4App Documentation﻿
﻿Parse Server Guide﻿
﻿Flutter Official Documentation﻿
﻿Stripe API Reference﻿
﻿Flutter Stripe Package﻿
Happy Coding!
Updated 14 Sep 2024
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