# Using the Presentation Handler

You can provide a `PaywallPresentationHandler` to `register`, whose functions provide status updates for a paywall:

* `onDismiss`: Called when the paywall is dismissed. Accepts a `PaywallInfo` object containing info about the dismissed paywall, and there is a `PaywallResult` informing you of any transaction.
* `onPresent`: Called when the paywall did present. Accepts a `PaywallInfo` object containing info about the presented paywall.
* `onError`: Called when an error occurred when trying to present a paywall. Accepts an `Error` indicating why the paywall could not present.
* `onSkip`: Called when a paywall is skipped. Accepts a `PaywallSkippedReason` enum indicating why the paywall was skipped.
* `onCustomCallback` *(Android 2.7.0+)*: Called when the paywall requests a custom callback. Accepts a `CustomCallback` containing the callback name and optional variables, and returns a `CustomCallbackResult` indicating success or failure with optional data to pass back to the paywall.

## Tab

```swift Swift
let handler = PaywallPresentationHandler()
handler.onDismiss { paywallInfo, result in
  print("The paywall dismissed. PaywallInfo: \(paywallInfo). Result: \(result)")
}
handler.onPresent { paywallInfo in
  print("The paywall presented. PaywallInfo:", paywallInfo)
}
handler.onError { error in
  print("The paywall presentation failed with error \(error)")
}
handler.onSkip { reason in
  switch reason {
  case .holdout(let experiment):
    print("Paywall not shown because user is in a holdout group in Experiment: \(experiment.id)")
  case .noAudienceMatch:
    print("Paywall not shown because user doesn't match any audiences.")
  case .placementNotFound:
    print("Paywall not shown because this placement isn't part of a campaign.")
  }
}

Superwall.shared.register(placement: "campaign_trigger", handler: handler) {
  // Feature launched
}
```

## Tab

```swift Objective-C
SWKPaywallPresentationHandler *handler = [[SWKPaywallPresentationHandler alloc] init];

[handler onDismiss:^(SWKPaywallInfo * _Nonnull paywallInfo,
                         enum SWKPaywallResult result,
                         SWKStoreProduct * _Nullable product) {
  NSLog(@"The paywall presented. PaywallInfo: %@ - result: %ld", paywallInfo, (long)result);
}];

[handler onPresent:^(SWKPaywallInfo * _Nonnull paywallInfo) {
  NSLog(@"The paywall presented. PaywallInfo: %@", paywallInfo);
}];

[handler onError:^(NSError * _Nonnull error) {
  NSLog(@"The paywall presentation failed with error %@", error);
}];

[handler onSkip:^(enum SWKPaywallSkippedReason reason) {
  switch (reason) {
    case SWKPaywallSkippedReasonUserIsSubscribed:
      NSLog(@"Paywall not shown because user is subscribed.");
      break;
    case SWKPaywallSkippedReasonHoldout:
      NSLog(@"Paywall not shown because user is in a holdout group.");
      break;
    case SWKPaywallSkippedReasonNoAudienceMatch:
      NSLog(@"Paywall not shown because user doesn't match any audiences.");
      break;
    case SWKPaywallSkippedReasonPlacementNotFound:
      NSLog(@"Paywall not shown because this placement isn't part of a campaign.");
      break;
    case SWKPaywallSkippedReasonNone:
      // The paywall wasn't skipped.
      break;
  }
}];

[[Superwall sharedInstance] registerWithPlacement:@"campaign_trigger" params:nil handler:handler feature:^{
  // Feature launched.
}];
```

## Tab

```kotlin Kotlin
val handler = PaywallPresentationHandler()
handler.onDismiss { paywallInfo, result ->
  println("The paywall dismissed. PaywallInfo: ${it}")
}
handler.onPresent {
  println("The paywall presented. PaywallInfo: ${it}")
}
handler.onError {
  println("The paywall errored. Error: ${it}")
}
handler.onSkip {
  when (it) {
    is PaywallSkippedReason.PlacementNotFound -> {
      println("The paywall was skipped because the placement was not found.")
    }
    is PaywallSkippedReason.Holdout -> {
      println("The paywall was skipped because the user is in a holdout group.")
    }
    is PaywallSkippedReason.NoAudienceMatch -> {
      println("The paywall was skipped because no audience matched.")
    }
  }
}

Superwall.instance.register(placement = "campaign_trigger", handler = handler) {
    // Feature launched
}
```

## Tab

```dart Flutter
PaywallPresentationHandler handler = PaywallPresentationHandler();
handler.onPresent((paywallInfo) async {
  String name = await paywallInfo.name;
  print("Handler (onPresent): $name");
});
handler.onDismiss((paywallInfo, paywallResult) async {
  String name = await paywallInfo.name;
  print("Handler (onDismiss): $name");
});
handler.onError((error) {
  print("Handler (onError): ${error}");
});
handler.onSkip((skipReason) async {
  String description = await skipReason.description;

  if (skipReason is PaywallSkippedReasonHoldout) {
    print("Handler (onSkip): $description");

    final experiment = await skipReason.experiment;
    final experimentId = await experiment.id;
    print("Holdout with experiment: ${experimentId}");
  } else if (skipReason is PaywallSkippedReasonNoAudienceMatch) {
    print("Handler (onSkip): $description");
  } else if (skipReason is PaywallSkippedReasonPlacementNotFound) {
    print("Handler (onSkip): $description");
  } else {
    print("Handler (onSkip): Unknown skip reason");
  }
});

Superwall.shared.registerPlacement("campaign_trigger", handler: handler, feature: () {
  // Feature launched
});
```

## Tab

```typescript React Native
const handler = new PaywallPresentationHandler()
handler.onPresent((paywallInfo) => {
  const name = paywallInfo.name
  console.log(`Handler (onPresent): ${name}`)
})
handler.onDismiss((paywallInfo, paywallResult) => {
  const name = paywallInfo.name
  console.log(`Handler (onDismiss): ${name}`)
})
handler.onError((error) => {
  console.log(`Handler (onError): ${error}`)
})
handler.onSkip((skipReason) => {
  const description = skipReason.description

  if (skipReason instanceof PaywallSkippedReasonHoldout) {
    console.log(`Handler (onSkip): ${description}`)
    const experiment = skipReason.experiment
    const experimentId = experiment.id
    console.log(`Holdout with experiment: ${experimentId}`)
  } else if (skipReason instanceof PaywallSkippedReasonNoAudienceMatch) {
    console.log(`Handler (onSkip): ${description}`)
  } else if (skipReason instanceof PaywallSkippedReasonPlacementNotFound) {
    console.log(`Handler (onSkip): ${description}`)
  } else {
    console.log(`Handler (onSkip): Unknown skip reason`)
  }
})

Superwall.shared.register({
  placement: 'campaign_trigger',
  handler: handler,
  feature: () => {
    // Feature launched
  }
});
```



:::expo
```tsx React Native
import { usePlacement } from "expo-superwall";
import { Button } from "react-native";

function PaywallButton() {
  const { registerPlacement } = usePlacement({
    onPresent: (paywallInfo) => {
      console.log(`Handler (onPresent): ${paywallInfo.name}`);
    },
    onDismiss: (paywallInfo, paywallResult) => {
      console.log(`Handler (onDismiss): ${paywallInfo.name}`);
      // Check the result to see if user purchased
      console.log(`Result:`, paywallResult);
    },
    onError: (error) => {
      console.log(`Handler (onError): ${error}`);
    },
    onSkip: (skipReason) => {
      console.log(`Handler (onSkip):`, skipReason);
    },
  });

  const handlePress = async () => {
    await registerPlacement({
      placement: 'campaign_trigger',
      feature: () => {
        // Feature launched
        console.log("Feature unlocked!");
      },
    });
  };

  return <Button onPress={handlePress} title="Show Paywall" />;
}
```
:::

> **Tip**

Wanting to see which product was just purchased from a paywall? Use `onDismiss` and the `result`
parameter. Or, you can use the
[SuperwallDelegate](/docs/sdk/guides/3rd-party-analytics#using-events-to-see-purchased-products).