Interstitial ads custom events

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Prerequisites

Complete the custom events setup.

Request an interstitial ad

When the custom event line item is reached in the waterfall mediation chain, the loadInterstitial:adConfiguration:completionHandler: method is called on the class name you provided when creating a custom event. In this case, that method is in SampleCustomEvent, which then calls the loadInterstitial:adConfiguration:completionHandler: method in SampleCustomEventInterstitial.

To request an interstitial ad, create or modify a class that implements GADMediationAdapter and loadInterstitial:adConfiguration:completionHandler:. If a class that extends GADMediationAdapter already exists, implement loadInterstitial:adConfiguration:completionHandler: there. Additionally, create a new class to implement GADMediationInterstitialAd.

In our custom event example, SampleCustomEvent implements the GADMediationAdapter interface and then delegates to SampleCustomEventInterstitial.

Swift

import GoogleMobileAds

class SampleCustomEvent: NSObject, GADMediationAdapter {

  fileprivate var interstitialAd: SampleCustomEventInterstitial?
  ...

  func loadInterstitial(
    for adConfiguration: GADMediationInterstitialAdConfiguration,
    completionHandler: @escaping GADMediationInterstitialLoadCompletionHandler
  ) {
    self.interstitialAd = SampleCustomEventInterstitial()
    self.interstitialAd?.loadInterstitial(
      for: adConfiguration, completionHandler: completionHandler)
  }
}

Objective-C

#import "SampleCustomEvent.h"

@implementation SampleCustomEvent

SampleCustomEventInterstitial *sampleInterstitial;

- (void)loadInterstitialForAdConfiguration:
            (GADMediationInterstitialAdConfiguration *)adConfiguration
                         completionHandler:
                             (GADMediationInterstitialLoadCompletionHandler)
                                 completionHandler {
  sampleInterstitial = [[SampleCustomEventInterstitial alloc] init];
  [sampleInterstitial loadInterstitialForAdConfiguration:adConfiguration
                                       completionHandler:completionHandler];
}

SampleCustomEventInterstitial is responsible for the following tasks:

  • Loading the interstitial ad and invoking a GADMediationInterstitialAdLoadCompletionHandler method once loading completes

  • Implementing the GADMediationInterstitialAd protocol

  • Receiving and reporting ad event callbacks to the Google Mobile Ads SDK

The optional parameter defined in the Ad Manager UI is passed into your custom event as part of the loadInterstitial:adConfiguration:completionHandler: method. The parameter can be accessed through adConfiguration.credentials.settings[@"parameter"]. This parameter is typically an ad unit identifier that an ad network SDK requires when instantiating an ad object.

Swift

import GoogleMobileAds

class SampleCustomEventInterstitial: NSObject, GADMediationInterstitialAd {
  /// The Sample Ad Network interstitial ad.
  var interstitial: SampleInterstitial?

  /// The ad event delegate to forward ad rendering events to the Google Mobile Ads SDK.
  var delegate: GADMediationInterstitialAdEventDelegate?

  var completionHandler: GADMediationInterstitialLoadCompletionHandler?

  func loadInterstitial(
    for adConfiguration: GADMediationInterstitialAdConfiguration,
    completionHandler: @escaping GADMediationInterstitialLoadCompletionHandler
  ) {
    interstitial = SampleInterstitial.init(
      adUnitID: adConfiguration.credentials.settings["parameter"] as? String)
    interstitial?.delegate = self
    let adRequest = SampleAdRequest()
    adRequest.testMode = adConfiguration.isTestRequest
    self.completionHandler = completionHandler
    interstitial?.fetchAd(adRequest)
  }

  func present(from viewController: UIViewController) {
    if let interstitial = interstitial, interstitial.isInterstitialLoaded {
      interstitial.show()
    }
  }
}

Objective-C

#import "SampleCustomEventInterstitial.h"

@interface SampleCustomEventInterstitial () <SampleInterstitialAdDelegate,
                                             GADMediationInterstitialAd> {
  /// The sample interstitial ad.
  SampleInterstitial *_interstitialAd;

  /// The completion handler to call when the ad loading succeeds or fails.
  GADMediationInterstitialLoadCompletionHandler _loadCompletionHandler;

  /// The ad event delegate to forward ad rendering events to the Google Mobile
  /// Ads SDK.
  id <GADMediationInterstitialAdEventDelegate> _adEventDelegate;
}
@end

- (void)loadInterstitialForAdConfiguration:
            (GADMediationInterstitialAdConfiguration *)adConfiguration
                         completionHandler:
                             (GADMediationInterstitialLoadCompletionHandler)
                                 completionHandler {
  __block atomic_flag completionHandlerCalled = ATOMIC_FLAG_INIT;
  __block GADMediationInterstitialLoadCompletionHandler
      originalCompletionHandler = [completionHandler copy];

  _loadCompletionHandler = ^id<GADMediationInterstitialAdEventDelegate>(
      _Nullable id<GADMediationInterstitialAd> ad, NSError *_Nullable error) {
    // Only allow completion handler to be called once.
    if (atomic_flag_test_and_set(&completionHandlerCalled)) {
      return nil;
    }

    id<GADMediationInterstitialAdEventDelegate> delegate = nil;
    if (originalCompletionHandler) {
      // Call original handler and hold on to its return value.
      delegate = originalCompletionHandler(ad, error);
    }

    // Release reference to handler. Objects retained by the handler will also
    // be released.
    originalCompletionHandler = nil;

    return delegate;
  };

  NSString *adUnit = adConfiguration.credentials.settings[@"parameter"];
  _interstitialAd = [[SampleInterstitial alloc] initWithAdUnitID:adUnit];
  _interstitialAd.delegate = self;
  SampleAdRequest *adRequest = [[SampleAdRequest alloc] init];
  adRequest.testMode = adConfiguration.isTestRequest;
  [_interstitialAd fetchAd:adRequest];
}

Whether the ad is successfully fetched or encounters an error, you would call GADMediationInterstitialLoadCompletionHandler. In the event of success, pass through the class that implements GADMediationInterstitialAd with a nil value for the error parameter; in the event of failure, pass through the error you encountered.

Typically, these methods are implemented inside callbacks from the third-party SDK your adapter implements. For this example, the Sample SDK has a SampleInterstitialAdDelegate with relevant callbacks:

Swift

func interstitialDidLoad(_ interstitial: SampleInterstitial) {
  if let handler = completionHandler {
    delegate = handler(self, nil)
  }
}

func interstitial(
  _ interstitial: SampleInterstitial,
  didFailToLoadAdWith errorCode: SampleErrorCode
) {
  let error =
    SampleCustomEventUtilsSwift.SampleCustomEventErrorWithCodeAndDescription(
      code: SampleCustomEventErrorCodeSwift
        .SampleCustomEventErrorAdLoadFailureCallback,
      description:
        "Sample SDK returned an ad load failure callback with error code: \(errorCode)"
    )
  if let handler = completionHandler {
    delegate = handler(nil, error)
  }
}

Objective-C

- (void)interstitialDidLoad:(SampleInterstitial *)interstitial {
  _adEventDelegate = _loadCompletionHandler(self, nil);
}

- (void)interstitial:(SampleInterstitial *)interstitial
    didFailToLoadAdWithErrorCode:(SampleErrorCode)errorCode {
  NSError *error = SampleCustomEventErrorWithCodeAndDescription(
      SampleCustomEventErrorAdLoadFailureCallback,
      [NSString stringWithFormat:@"Sample SDK returned an ad load failure "
                                 @"callback with error code: %@",
                                 errorCode]);
  _adEventDelegate = _loadCompletionHandler(nil, error);
}

GADMediationInterstitialAd requires implementing a present method to display the ad:

Swift

func present(from viewController: UIViewController) {
  if let interstitial = interstitial, interstitial.isInterstitialLoaded {
    interstitial.show()
  }
}

Objective-C

- (void)presentFromViewController:(UIViewController *)viewController {
  if ([_interstitialAd isInterstitialLoaded]) {
    [_interstitialAd show];
  } else {
    NSError *error = SampleCustomEventErrorWithCodeAndDescription(
        SampleCustomEventErrorAdNotLoaded,
        [NSString stringWithFormat:@"The interstitial ad failed to present "
                                   @"because the ad was not loaded."]);
    [_adEventDelegate didFailToPresentWithError:error]
  }
}

Forward mediation events to the Google Mobile Ads SDK

Once you've called GADMediationInterstitialLoadCompletionHandler with a loaded ad, the returned GADMediationInterstitialAdEventDelegate delegate object can then be used by the adapter to forward presentation events from the third-party SDK to the Google Mobile Ads SDK. The SampleCustomEventInterstitial class implements the SampleInterstitialAdDelegate protocol to forward callbacks from the sample ad network to the Google Mobile Ads SDK.

It's important that your custom event forwards as many of these callbacks as possible, so that your app receives these equivalent events from the Google Mobile Ads SDK. Here's an example of using callbacks:

Swift

func interstitialWillPresentScreen(_ interstitial: SampleInterstitial) {
  delegate?.willPresentFullScreenView()
  delegate?.reportImpression()
}

func interstitialWillDismissScreen(_ interstitial: SampleInterstitial) {
  delegate?.willDismissFullScreenView()
}

func interstitialDidDismissScreen(_ interstitial: SampleInterstitial) {
  delegate?.didDismissFullScreenView()
}

func interstitialWillLeaveApplication(_ interstitial: SampleInterstitial) {
  delegate?.reportClick()
}

Objective-C

- (void)interstitialWillPresentScreen:(SampleInterstitial *)interstitial {
  [_adEventDelegate willPresentFullScreenView];
  [_adEventDelegate reportImpression];
}

- (void)interstitialWillDismissScreen:(SampleInterstitial *)interstitial {
  [_adEventDelegate willDismissFullScreenView];
}

- (void)interstitialDidDismissScreen:(SampleInterstitial *)interstitial {
  [_adEventDelegate didDismissFullScreenView];
}

- (void)interstitialWillLeaveApplication:(SampleInterstitial *)interstitial {
  [_adEventDelegate reportClick];
}

This completes the custom events implementation for interstitial ads. The full example is available on GitHub. You can use it with an ad network that is already supported or modify it to display custom event interstitial ads.