# Using the Superwall Delegate

Use Superwall's delegate to extend our SDK's functionality across several surface areas by assigning to the `delegate` property:

:::flutter
```dart
import 'package:superwallkit_flutter/superwallkit_flutter.dart';

class SWDelegate extends SuperwallDelegate {
  // Implement delegate methods here
}

// When configuring the SDK...
void configureSDK() {
  Superwall.shared.setDelegate(SWDelegate());
}
```
:::

Some common use cases for using the Superwall delegate include:

* **Custom actions:** [Respond to custom tap actions from a paywall.](/docs/sdk/guides/advanced/custom-paywall-actions#custom-paywall-actions)
* **Respond to purchases:** [See which product was purchased from the presented paywall.](/docs/sdk/guides/advanced/viewing-purchased-products)
* **Analytics:** [Forward events from Superwall to your own analytics.](/docs/sdk/guides/3rd-party-analytics)

Below are some commonly used implementations when using the delegate.

Superwall Events [#superwall-events]

Most of what occurs in Superwall can be viewed using the delegate method to respond to events:

:::flutter
```dart
class _MyAppState extends State<MyApp> implements SuperwallDelegate {
  @override
  Future<void> handleSuperwallEvent(SuperwallEventInfo eventInfo) async {
    switch (eventInfo.event.type) {
      // Handle any other event types as needed
      case PlacementType.transactionComplete:
        final product = eventInfo.params?['product'];
        logging.info('Transaction complete event received with product: $product');
        break;
      default:
        logging.info('Unhandled event type: ${eventInfo.event.type}');
        break;
    }
  }
}
```
:::

Paywall Custom Actions [#paywall-custom-actions]

Using the [custom tap action](/docs/sdk/guides/advanced/custom-paywall-actions#custom-paywall-actions), you can respond to any arbitrary event from a paywall:

:::flutter
```dart
class _MyAppState extends State<MyApp> implements SuperwallDelegate {
  final logging = Logging();

  @override
  void handleCustomPaywallAction(String name) {
    logging.info('handleCustomPaywallAction: $name');
  }
}
```
:::

Subscription status changes [#subscription-status-changes]

You can be informed of subscription status changes using the delegate. If you need to set or handle the status on your own, use a [purchase controller](/docs/sdk/guides/advanced-configuration) — this function is only for informational, tracking or similar purposes:

:::flutter
```dart
class _MyAppState extends State<MyApp> implements SuperwallDelegate {
  final logging = Logging();

  @override
  void subscriptionStatusDidChange(SubscriptionStatus newValue) {
    logging.info('subscriptionStatusDidChange: $newValue');
  }
}
```
:::

Paywall events [#paywall-events]

The delegate also has callbacks for several paywall events, such dismissing, presenting, and more. Here's an example:

:::flutter
```dart
class _MyAppState extends State<MyApp> implements SuperwallDelegate {
  final logging = Logging();

  @override
  void didPresentPaywall(PaywallInfo paywallInfo) {
    logging.info('didPresentPaywall: $paywallInfo');
  }
}
```
:::