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Version: 8.2 (Current)

Purchase Lifecycle

IapKit - Fraud-proof your in-app purchases

Understanding the complete purchase lifecycle is essential for proper implementation.

OpenIAP Lifecycle Documentation​

For detailed lifecycle documentation, flow diagrams, and state management:

👉 OpenIAP Lifecycle Documentation

Purchase Flow

Lifecycle Phases​

1. Connection Phase​

// Initialize connection to store
final connected = await FlutterInappPurchase.instance.initConnection();

States: disconnected → connecting → connected

2. Product Discovery Phase​

// Fetch available products
final products = await iap.fetchProducts(
  skus: productIds,
  type: ProductQueryType.inApp,
);

States: idle → loading → loaded / error

3. Purchase Initiation Phase​

// User initiates purchase
await iap.requestPurchase(
  sku: productId,
  obfuscatedAccountIdAndroid: userId,
);

States: idle → purchasing → purchased / failed / cancelled

4. Transaction Processing Phase​

Platform handles payment and returns result via streams:

_purchaseUpdatedSubscription = iap.purchaseUpdatedListener.listen(
  (purchase) {
    // Purchase successful
    debugPrint('Purchase received: ${purchase.productId}');
  },
);

_purchaseErrorSubscription = iap.purchaseErrorListener.listen(
  (error) {
    // Purchase failed
    debugPrint('Purchase error: ${error.message}');
  },
);

5. Content Delivery Phase​

// Validate purchase on your server
final isValid = await verifyPurchaseOnServer(purchase);
if (isValid) {
  await deliverContent(purchase.productId);
}

6. Transaction Finalization Phase​

// Finish transaction (consume/acknowledge)
await iap.finishTransaction(
  purchase: purchase,
  isConsumable: true,
);

States: pending → finished

Purchase State Management​

Track Purchase States​

enum PurchaseState {
  idle,
  loading,
  purchasing,
  purchased,
  failed,
  cancelled,
}

class PurchaseManager extends ChangeNotifier {
  PurchaseState _state = PurchaseState.idle;
  PurchaseState get state => _state;

  void setState(PurchaseState newState) {
    _state = newState;
    notifyListeners();
  }
}

Pending Transactions​

Handle purchases that didn't complete:

Future<void> checkPendingPurchases() async {
  final purchases = await iap.getAvailablePurchases();

  for (final purchase in purchases) {
    // Check if already delivered
    final isDelivered = await checkIfDelivered(purchase.transactionId);

    if (!isDelivered) {
      // Deliver and finish
      await deliverContent(purchase.productId);
      await iap.finishTransaction(
        purchase: purchase,
        isConsumable: false,
      );
    }
  }
}

Best Practices​

  1. Initialize early - Connect to store on app startup
  2. Check pending purchases - Handle incomplete transactions on launch
  3. Maintain state - Track purchase states for UI feedback
  4. Clean up properly - End connection when no longer needed

Next Steps​