helium_flutter

Installation

Add the helium_flutter package to your pubspec.yaml:

dependencies:
  helium_flutter: ^0.0.1

Then run:

flutter pub get

Make sure that Swift Package Manager Support is enabled:

flutter upgrade
flutter config --enable-swift-package-manager

See Google's guide on this for more details.

Configuration

Set up your HeliumCallbacks

To integrate Helium paywalls, create a class that implements the HeliumCallbacks interface. This class is responsible for handling the purchase logic for your paywalls.

abstract class HeliumCallbacks {
  // [REQUIRED] - Trigger the purchase of a product with the provided product ID.
  // This method should return a HeliumTransactionStatus enum.
  Future<HeliumTransactionStatus> makePurchase(String productId);

  // [OPTIONAL] - Restore any existing subscriptions.
  // This method should return a boolean indicating whether the restore was successful.
  Future<bool> restorePurchases(bool status);

  // [OPTIONAL] - Custom analytics/error logging for paywall/helium related events.
  // By default, events are logged to your analytics service, but you can override 
  // this method to add additional custom logging/handling.
  Future<void> onPaywallEvent(Map<String, dynamic> heliumPaywallEvent);
}

The HeliumTransactionStatus enum defines the possible states of a paywall transaction:

enum HeliumTransactionStatus { 
  purchased, 
  failed, 
  cancelled, 
  restored, 
  pending 
}

Example Callbacks Implementation:

Basic Implementation

Here's a basic implementation of the HeliumCallbacks interface:

import 'package:helium_flutter/helium_flutter.dart';
import 'dart:developer';

class PaymentCallbacks implements HeliumCallbacks {
  @override
  Future<HeliumTransactionStatus> makePurchase(String productId) async {
    log('makePurchase: $productId');
    // Implement your purchase logic here
    return HeliumTransactionStatus.purchased;
  }

  @override
  Future<bool> restorePurchases(bool status) async {
    log('restorePurchases: $status');
    // Implement your restore logic here
    return status;
  }

  @override
  Future<void> onPaywallEvent(Map<String, dynamic> heliumPaywallEvent) async {
    log('onPaywallEvent: $heliumPaywallEvent');
    // Handle paywall events here
  }
}

RevenueCat Implementation

import 'package:helium_flutter/helium_flutter.dart';
import 'package:purchases_flutter/purchases_flutter.dart';
import 'dart:developer';

class RevenueCatCallbacks implements HeliumCallbacks {
  @override
  Future<HeliumTransactionStatus> makePurchase(String productId) async {
    try {
      log('RevenueCat making purchase: $productId');
      final offerings = await Purchases.getOfferings();
      
      Package? packageToPurchase;
      
      // Find the package in current offering
      if (offerings.current != null) {
        for (var package in offerings.current!.availablePackages) {
          if (package.storeProduct.identifier == productId) {
            packageToPurchase = package;
            break;
          }
        }
      }
      
      // If not found in current, search all offerings
      if (packageToPurchase == null) {
        for (var offering in offerings.all.values) {
          for (var package in offering.availablePackages) {
            if (package.storeProduct.identifier == productId) {
              packageToPurchase = package;
              break;
            }
          }
          if (packageToPurchase != null) break;
        }
      }
      
      if (packageToPurchase == null) {
        log('Product not found in any offering: $productId');
        return HeliumTransactionStatus.failed;
      }
      
      final purchaseResult = await Purchases.purchasePackage(packageToPurchase);
      
      // Check if the purchase was successful by looking at entitlements
      if (purchaseResult.customerInfo.entitlements.active.isNotEmpty) {
        return HeliumTransactionStatus.purchased;
      } else {
        return HeliumTransactionStatus.failed;
      }
    } catch (e) {
      log('RevenueCat purchase error: $e');
      if (e is PurchasesErrorCode) {
        if (e == PurchasesErrorCode.purchaseCancelledError) {
          return HeliumTransactionStatus.cancelled;
        } else if (e == PurchasesErrorCode.paymentPendingError) {
          return HeliumTransactionStatus.pending;
        }
      }
      return HeliumTransactionStatus.failed;
    }
  }

  @override
  Future<bool> restorePurchases(bool status) async {
    try {
      log('RevenueCat restoring purchases');
      final restoredInfo = await Purchases.restorePurchases();
      return restoredInfo.entitlements.active.isNotEmpty;
    } catch (e) {
      log('RevenueCat restore error: $e');
      return false;
    }
  }

  @override
  Future<void> onPaywallEvent(Map<String, dynamic> heliumPaywallEvent) async {
    log('RevenueCat paywall event: $heliumPaywallEvent');
    // Handle specific events as needed
    final eventType = heliumPaywallEvent['type'];
    
    if (eventType == 'subscriptionSucceeded') {
      // Handle successful subscription
      final productId = heliumPaywallEvent['productKey'];
      log('Subscription succeeded for product: $productId');
      
      // Add your custom analytics tracking here
    }
  }
}

Initialize Helium and Download Paywall Configs

In your app's initialization code (typically in main.dart or your root widget), add the following to download paywall configurations:

import 'package:helium_flutter/helium_flutter.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  
  // Create your callbacks implementation
  PaymentCallbacks paymentCallbacks = PaymentCallbacks();
  
  // Initialize Helium
  final heliumFlutter = HeliumFlutter();
  heliumFlutter.initialize(
    // You'll get this from Helium founders during setup!
    apiKey: "<your-helium-api-key>",
    
    // The callbacks implementation you created earlier
    callbacks: paymentCallbacks,
    
    // If set, a custom API endpoint (usually provided by Helium)
    customAPIEndpoint: "https://api-v2.tryhelium.com/on-launch",
    
    // If set, a custom user ID to use instead of Helium's
    customUserId: "your-custom-user-id", // Optional
    
    // Custom user traits for targeting and personalization
    customUserTraits: {
      "exampleUserTrait": "test_value",
      "subscriptionStatus": "active",
      "userIntent": "upgrade",
      "numericalValue": 3.0,
    }, // Optional
  );
  
  runApp(const MyApp());
}

Passing Custom User Traits

Custom user traits can be any key-value pairs where the value is a serializable type (String, num, bool, etc.). These traits can be used for targeting, personalization, and dynamic content in your paywalls.

Passing in a Custom User ID

By default, Helium generates a UUID per app session to identify users. You can override this with your own custom user ID (e.g., from a 3rd party analytics service) by passing it in the initialize method or by explicitly calling overrideUserId:

// Set a custom user ID
await heliumFlutter.overrideUserId(
  newUserId: "your-custom-user-id", 
  traits: {
    "exampleTrait": "value",
    "userType": "premium"
  }
);

Checking Download Status

After initialization, you can check the status of the paywall configuration download:

String downloadStatus = await heliumFlutter.getDownloadStatus() ?? 'Unknown';

The download status will be one of the following:

• "notDownloadedYet": The download has not been initiated or is still in progress.
• "downloadSuccess": The download was successful.
• "downloadFailure": The download failed.

You can use this to handle different states in your app.

Checking if Paywalls are Loaded

You can also check if paywalls have been loaded successfully:

bool paywallsLoaded = await heliumFlutter.paywallsLoaded() ?? false;

Presenting Paywalls

There are several ways to present Helium paywalls in your Flutter app:

Via Direct Method Call

You can present a paywall programmatically using the presentUpsell method:

ElevatedButton(
  onPressed: () async {
    await heliumFlutter.presentUpsell(trigger: 'onboarding');
  },
  child: Text('Show Premium Features'),
),

The trigger parameter is a unique identifier for the paywall trigger point in your app. Helium uses this to track and optimize the paywall for each trigger point.

Via Widget Integration

You can also use the UpsellViewForTrigger widget to embed a paywall directly in your widget tree:

class ViewForTriggerPage extends StatelessWidget {
  const ViewForTriggerPage({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: UpsellViewForTrigger(trigger: 'onboarding'),
    );
  }
}

Hiding Paywalls

To programmatically hide a paywall:

bool hideResult = await heliumFlutter.hideUpsell() ?? false;

Handling Custom Dismissal Actions

You can implement custom dismissal logic by handling paywall events in your HeliumCallbacks implementation:

@override
Future<void> onPaywallEvent(Map<String, dynamic> heliumPaywallEvent) async {
  final eventType = heliumPaywallEvent['type'];
  
  if (eventType == 'ctaPressed') {
    final ctaName = heliumPaywallEvent['ctaName'];
    final triggerName = heliumPaywallEvent['triggerName'];
    
    if (ctaName == 'dismiss') {
      // Handle custom dismissal logic here
      // For example, navigate back or show a different screen
    }
  }
}

Getting User ID

To retrieve the Helium user ID:

String userId = await heliumFlutter.getHeliumUserId() ?? 'Unknown';

Testing

Documentation for testing will be provided separately. After integration, please message us directly to get set up with a test app + in-app test support.