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Version: 7.0

Subscription Flow

Source Code: subscription_flow_screen.dart

This example demonstrates how to implement subscription purchases with support for upgrades, downgrades, and subscription management.

Key Features​

  • Fetch subscription products
  • Handle subscription purchases
  • Check active subscriptions
  • Manage subscription upgrades/downgrades (Android)
  • Listen to subscription events

Implementation Overview​

1. Set Up Listeners​

StreamSubscription<Purchase>? _purchaseUpdatedSubscription;
StreamSubscription<PurchaseError>? _purchaseErrorSubscription;

void _setupListeners() {
  _purchaseUpdatedSubscription = iap.purchaseUpdatedListener.listen(
    (purchase) {
      _handlePurchase(purchase);
    },
  );

  _purchaseErrorSubscription = iap.purchaseErrorListener.listen(
    (error) {
      _handleError(error);
    },
  );
}

2. Fetch Subscription Products​

final result = await iap.fetchProducts(
  ProductRequest(
    skus: ['monthly_sub', 'yearly_sub'],
    type: ProductQueryType.Subs,
  ),
);

if (result is FetchProductsResultSubscriptions) {
  final subscriptions = result.value ?? [];
  for (final product in subscriptions) {
    if (product is ProductSubscriptionIOS) {
      debugPrint('iOS Subscription: ${product.displayName}');
    } else if (product is ProductSubscriptionAndroid) {
      debugPrint('Android Subscription: ${product.title}');
    }
  }
}

3. Check Active Subscriptions​

// Lightweight check - returns only subscription IDs and expiry dates
final summaries = await iap.getActiveSubscriptions(['monthly_sub']);
if (summaries.isNotEmpty) {
  debugPrint('Active subscription: ${summaries.first.productId}');
  debugPrint('Expires: ${summaries.first.expirationDateIOS}');
}

// Detailed check - returns full purchase objects
final purchases = await iap.getAvailablePurchases(
  PurchaseOptions(onlyIncludeActiveItemsIOS: true),
);

4. Purchase Subscription​

await iap.requestPurchase(
  RequestPurchaseProps.subs((
    ios: RequestPurchaseIosProps(
      sku: 'monthly_sub',
      quantity: 1,
    ),
    android: RequestPurchaseAndroidProps(
      skus: ['monthly_sub'],
    ),
    useAlternativeBilling: null,
  )),
);

5. Upgrade/Downgrade Subscription (Android)​

await iap.requestPurchase(
  RequestPurchaseProps.subs((
    ios: RequestPurchaseIosProps(
      sku: 'yearly_sub',
      quantity: 1,
    ),
    android: RequestPurchaseAndroidProps(
      skus: ['yearly_sub'],
      replacementModeAndroid: AndroidReplacementMode.withTimeProration,
    ),
    useAlternativeBilling: null,
  )),
);

Android Replacement Modes​

enum AndroidReplacementMode {
  withTimeProration,      // 1: Credit unused time towards new subscription
  chargeProratedPrice,    // 2: Charge prorated price immediately
  withoutProration,       // 3: No credit for unused time
  deferred,               // 4: New subscription starts at next renewal
  chargeFullPrice,        // 5: Charge full price immediately
}

Best Practices​

  1. Use lightweight checks - Use getActiveSubscriptions() for quick status checks
  2. Verify server-side - Always validate subscription status on your backend
  3. Handle upgrades properly - Choose appropriate replacement mode for Android
  4. Check subscription status - Regularly verify subscription validity
  5. Handle expiration - Monitor subscription expiry dates and renewal status