in-app-purchases.md

Let's use the latest version of the in_app_purchase package in Flutter to implement the API integration for getting courses, a single course, and applying promo codes.

Step 1: Add Dependencies

Ensure your pubspec.yaml file includes the latest in_app_purchase package:

dependencies:
  flutter:
    sdk: flutter
  in_app_purchase_storekit: ^0.3.0
  http: ^0.13.3

Step 2: API Endpoints in Laravel

Implement the Laravel endpoints to fetch course data and apply promo codes.

CoursesController.php

<?php

namespace App\Http\Controllers;

use App\Models\Course;
use App\Models\PromoCode;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;

class CoursesController extends Controller
{
    public function getCourses()
    {
        $courses = Course::all();
        return response()->json($courses);
    }

    public function getCourse($id)
    {
        $course = Course::find($id);
        if (!$course) {
            return response()->json(['error' => 'Course not found'], 404);
        }
        return response()->json($course);
    }

    public function applyPromoCode(Request $request)
    {
        $code = $request->input('code');
        $promo = PromoCode::where('code', $code)->first();

        if ($promo && $promo->isValid()) {
            return response()->json(['success' => true, 'discount' => $promo->discount]);
        }

        return response()->json(['success' => false, 'message' => 'Invalid promo code'], 400);
    }
}

Step 3: Flutter Integration

Implement the Flutter app to fetch courses, display them, and handle in-app purchases.

Fetching and Displaying Courses

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';

class Course {
  final String id;
  final String title;
  final String description;
  final double price;

  Course({required this.id, required this.title, required this.description, required this.price});

  factory Course.fromJson(Map<String, dynamic> json) {
    return Course(
      id: json['id'],
      title: json['title'],
      description: json['description'],
      price: json['price'],
    );
  }
}

class CoursesScreen extends StatefulWidget {
  @override
  _CoursesScreenState createState() => _CoursesScreenState();
}

class _CoursesScreenState extends State<CoursesScreen> {
  List<Course> _courses = [];

  @override
  void initState() {
    super.initState();
    _fetchCourses();
  }

  Future<void> _fetchCourses() async {
    final response = await http.get(Uri.parse('https://yourapi.com/api/courses'));
    if (response.statusCode == 200) {
      final List<dynamic> coursesJson = json.decode(response.body);
      setState(() {
        _courses = coursesJson.map((json) => Course.fromJson(json)).toList();
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Courses')),
      body: ListView.builder(
        itemCount: _courses.length,
        itemBuilder: (context, index) {
          final course = _courses[index];
          return ListTile(
            title: Text(course.title),
            subtitle: Text(course.description),
            trailing: Text('\$${course.price}'),
            onTap: () {
              // Navigate to course details and purchase screen
            },
          );
        },
      ),
    );
  }
}

In-App Purchase Integration

Implementing in-app purchases using the in_app_purchase_storekit package.

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

class PurchaseService {
  final InAppPurchase _iap = InAppPurchase.instance;

  void initialize() {
    _iap.purchaseStream.listen(_onPurchaseUpdated);
    _iap.restorePurchases();
  }

  void _onPurchaseUpdated(List<PurchaseDetails> purchaseDetailsList) {
    purchaseDetailsList.forEach((PurchaseDetails purchaseDetails) async {
      if (purchaseDetails.status == PurchaseStatus.pending) {
        // Handle pending state
      } else if (purchaseDetails.status == PurchaseStatus.error) {
        // Handle error state
      } else if (purchaseDetails.status == PurchaseStatus.purchased) {
        // Handle successful purchase
      }
    });
  }

  void buyProduct(ProductDetails productDetails) {
    final PurchaseParam purchaseParam = PurchaseParam(productDetails: productDetails);
    _iap.buyNonConsumable(purchaseParam: purchaseParam);
  }
}

Applying Promo Codes

void _applyPromoCode(String code) async {
  final response = await http.post(
    Uri.parse('https://yourapi.com/api/apply-promo-code'),
    headers: {
      'Authorization': 'Bearer ${your_token}',
      'Content-Type': 'application/json'
    },
    body: json.encode({'code': code}),
  );

  if (response.statusCode == 200) {
    final discount = json.decode(response.body)['discount'];
    // Apply discount logic
  } else {
    // Handle invalid promo code
  }
}

By following these steps, you can implement the required API endpoints and integrate them into your Flutter application with in-app purchases.

To properly organize your Flutter project, you should place the PurchaseService class in a dedicated service file. Here's a suggested structure:

Project Structure

lib/
├── main.dart
├── screens/
│   └── home_screen.dart
├── services/
│   └── purchase_service.dart

PurchaseService Implementation

Create a new file named purchase_service.dart under the services directory:

services/purchase_service.dart

import 'package:in_app_purchase/in_app_purchase.dart';

class PurchaseService {
  final InAppPurchase _iap = InAppPurchase.instance;

  void initialize() {
    _iap.purchaseStream.listen(_onPurchaseUpdated);
    _iap.restorePurchases();
  }

  void _onPurchaseUpdated(List<PurchaseDetails> purchaseDetailsList) {
    purchaseDetailsList.forEach((PurchaseDetails purchaseDetails) async {
      if (purchaseDetails.status == PurchaseStatus.pending) {
        // Handle pending state
      } else if (purchaseDetails.status == PurchaseStatus.error) {
        // Handle error state
      } else if (purchaseDetails.status == PurchaseStatus.purchased) {
        // Handle successful purchase
      }
    });
  }

  void buyProduct(ProductDetails productDetails) {
    final PurchaseParam purchaseParam = PurchaseParam(productDetails: productDetails);
    _iap.buyNonConsumable(purchaseParam: purchaseParam);
  }
}

Using PurchaseService in HomeScreen

screens/home_screen.dart

import 'package:flutter/material.dart';
import 'package:in_app_purchase/in_app_purchase.dart';
import '../services/purchase_service.dart';

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

class _HomeScreenState extends State<HomeScreen> {
  final PurchaseService _purchaseService = PurchaseService();
  List<ProductDetails> _products = [];

  @override
  void initState() {
    super.initState();
    _purchaseService.initialize();
    _loadProducts();
  }

  void _loadProducts() async {
    final bool available = await InAppPurchase.instance.isAvailable();
    if (!available) {
      // Handle store not available
      return;
    }

    const Set<String> _kIds = {'product_id_1', 'product_id_2'};
    final ProductDetailsResponse response = await InAppPurchase.instance.queryProductDetails(_kIds);
    if (response.notFoundIDs.isNotEmpty) {
      // Handle missing product IDs
    }

    setState(() {
      _products = response.productDetails;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Courses')),
      body: ListView.builder(
        itemCount: _products.length,
        itemBuilder: (context, index) {
          final product = _products[index];
          return ListTile(
            title: Text(product.title),
            subtitle: Text(product.description),
            trailing: Text('${product.price}'),
            onTap: () => _purchaseService.buyProduct(product),
          );
        },
      ),
    );
  }
}

By organizing your project this way, you ensure that the PurchaseService is reusable and keeps your code clean and modular.

eliyas5044/in-app-purchases.md