initConnection()

Initializes the connection to the platform's billing service.

Overview

The initConnection() method establishes a connection to the App Store (iOS) or Google Play Billing (Android). This method must be called before any other purchase-related operations.

Signature

Future<void> initConnection()

Returns

A Future that completes when the connection is established.

Throws

• PurchaseError with code E_ALREADY_INITIALIZED if the connection is already initialized
• PurchaseError with code E_NOT_INITIALIZED if the initialization fails

Platform Behavior

iOS

• Initializes StoreKit connection
• Sets up transaction observers
• Checks if the device can make payments

Android

• Initializes Google Play Billing client
• Establishes connection to Google Play services
• Sets up purchase update listeners

Usage Example

import 'package:flutter_inapp_purchase/flutter_inapp_purchase.dart';

class IAPService {
  final _iap = FlutterInappPurchase.instance;
  
  Future<void> initialize() async {
    try {
      // Initialize the connection
      await _iap.initConnection();
      print('IAP connection initialized successfully');
      
      // Set up listeners after initialization
      _setupListeners();
      
      // Now you can fetch products, make purchases, etc.
      await _fetchProducts();
      
    } catch (e) {
      if (e is PurchaseError) {
        switch (e.code) {
          case ErrorCode.E_ALREADY_INITIALIZED:
            print('IAP already initialized');
            break;
          case ErrorCode.E_NOT_INITIALIZED:
            print('Failed to initialize IAP: ${e.message}');
            break;
          default:
            print('IAP error: ${e.message}');
        }
      }
    }
  }
  
  void _setupListeners() {
    // Listen to purchase updates
    FlutterInappPurchase.purchaseUpdated.listen((purchase) {
      if (purchase != null) {
        _handlePurchase(purchase);
      }
    });
    
    // Listen to purchase errors
    FlutterInappPurchase.purchaseError.listen((error) {
      if (error != null) {
        _handleError(error);
      }
    });
  }
}

Best Practices

1. Initialize Early: Call initConnection() as early as possible in your app lifecycle, ideally when the app starts or when entering a store-related screen.

2. Handle Errors: Always wrap the initialization in a try-catch block to handle potential errors gracefully.

3. Check Connection State: Before making any purchase-related calls, ensure the connection is initialized.

4. Setup Listeners: Set up purchase update and error listeners immediately after successful initialization.

5. End Connection: Remember to call endConnection() when IAP functionality is no longer needed.

State Management Example

class IAPProvider extends ChangeNotifier {
  bool _isInitialized = false;
  bool get isInitialized => _isInitialized;
  
  String? _error;
  String? get error => _error;
  
  Future<void> init() async {
    if (_isInitialized) return;
    
    try {
      await FlutterInappPurchase.instance.initConnection();
      _isInitialized = true;
      _error = null;
      notifyListeners();
    } catch (e) {
      _error = e.toString();
      _isInitialized = false;
      notifyListeners();
    }
  }
  
  @override
  void dispose() {
    if (_isInitialized) {
      FlutterInappPurchase.instance.endConnection();
    }
    super.dispose();
  }
}

Related Methods

• finalize() - Closes the connection to the billing service
• getProducts() - Fetches available products (requires initialized connection)
• requestPurchase() - Initiates a purchase (requires initialized connection)

Migration Notes

From flutter_inapp_purchase v5.x

The method signature remains the same, but now includes expo-iap compatible error handling.

From expo-iap

This method replaces expo-iap's initialization pattern and provides the same functionality with enhanced error reporting.