When the custom event line item is reached in the waterfall mediation chain,
the loadBannerAd() 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 loadBannerAd()
method in SampleBannerCustomEventLoader.
To request a banner ad, create or modify a class that extends Adapter to
implement loadBannerAd(). Additionally, create a new class to implement
MediationBannerAd.
In our custom event example,
SampleCustomEvent extends the Adapter class and then delegates to
SampleBannerCustomEventLoader.
Receiving and reporting ad event callbacks to Google Mobile Ads SDK.
The optional parameter defined in the UI is
included in the ad configuration. The parameter can be accessed through
adConfiguration.getServerParameters().getString(MediationConfiguration.CUSTOM_EVENT_SERVER_PARAMETER_FIELD).
This parameter is typically an ad unit identifier that an ad network SDK
requires when instantiating an ad object.
Depending on whether the ad is successfully fetched or encounters an error, you
would call either
onSuccess()
or
onFailure().
onSuccess() is called by passing in an instance of the class that implements
MediationBannerAd.
Typically, these methods are implemented inside callbacks from the
third-party SDK your adapter implements. For this example, the Sample SDK
has a SampleAdListener with relevant callbacks:
Once onSuccess() is called, the returned MediationBannerAdCallback object
can then be used by the adapter to forward presentation events from the
third-party SDK to Google Mobile Ads SDK. The
SampleBannerCustomEventLoader class extends the SampleAdListener interface
to forward callbacks from the sample ad network to 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:
This completes the custom events implementation for banner 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 banner ads.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eTo request banner ads with custom events, extend the \u003ccode\u003eAdapter\u003c/code\u003e class and implement the \u003ccode\u003eloadBannerAd()\u003c/code\u003e method, delegating the ad loading process to a separate loader class.\u003c/p\u003e\n"],["\u003cp\u003eThe loader class is responsible for fetching the ad, handling ad events, and implementing the \u003ccode\u003eMediationBannerAd\u003c/code\u003e interface to interact with the Google Mobile Ads SDK.\u003c/p\u003e\n"],["\u003cp\u003eCustom events receive server parameters from Ad Manager, allowing them to be configured with ad unit IDs or other necessary information.\u003c/p\u003e\n"],["\u003cp\u003eUpon successful ad fetch, the loader class invokes \u003ccode\u003eonSuccess()\u003c/code\u003e on the \u003ccode\u003eMediationAdLoadCallback\u003c/code\u003e, providing an instance of the \u003ccode\u003eMediationBannerAd\u003c/code\u003e implementation.\u003c/p\u003e\n"],["\u003cp\u003eIt's crucial for custom events to forward relevant ad events from the third-party ad network to the Google Mobile Ads SDK using the \u003ccode\u003eMediationBannerAdCallback\u003c/code\u003e.\u003c/p\u003e\n"]]],["To request a banner ad, extend the `Adapter` class, implementing `loadBannerAd()`, and create a new class implementing `MediationBannerAd`. The `loadBannerAd()` method calls a loader class (e.g., `SampleBannerCustomEventLoader`) to load the ad, manage configuration, and handle callbacks. This loader class also implements `MediationBannerAd`, loading the banner and invoking `MediationAdLoadCallback` methods. The UI-defined custom event parameters are accessed via ad configuration. Upon success or failure, `onSuccess()` or `onFailure()` are invoked, and the `MediationBannerAdCallback` is utilized to forward third-party SDK presentation events.\n"],null,["Prerequisites\n\nComplete the [custom events setup](/ad-manager/mobile-ads-sdk/android/custom-events/setup).\n\nRequest a banner ad\n\nWhen the custom event line item is reached in the waterfall mediation chain,\nthe `loadBannerAd()` method is called on the class name you provided when\n[creating a custom\nevent](custom-events/setup#create). In this case,\nthat method is in `SampleCustomEvent`, which then calls the `loadBannerAd()`\nmethod in `SampleBannerCustomEventLoader`.\n\nTo request a banner ad, create or modify a class that extends `Adapter` to\nimplement `loadBannerAd()`. Additionally, create a new class to implement\n`MediationBannerAd`.\n\nIn our [custom event example](//github.com/googleads/googleads-mobile-android-mediation/blob/main/Example/customevent/src/main/java/com/google/ads/mediation/sample/customevent/SampleCustomEvent.java),\n`SampleCustomEvent` extends the `Adapter` class and then delegates to\n`SampleBannerCustomEventLoader`. \n\nJava \n\n```java\npackage com.google.ads.mediation.sample.customevent;\n\nimport com.google.android.gms.ads.mediation.Adapter;\nimport com.google.android.gms.ads.mediation.MediationAdConfiguration;\nimport com.google.android.gms.ads.mediation.MediationAdLoadCallback;\nimport com.google.android.gms.ads.mediation.MediationBannerAd;\nimport com.google.android.gms.ads.mediation.MediationBannerAdCallback;\n...\n\npublic class SampleCustomEvent extends Adapter {\n private SampleBannerCustomEventLoader bannerLoader;\n @Override\n public void loadBannerAd(\n @NonNull MediationBannerAdConfiguration adConfiguration,\n @NonNull MediationAdLoadCallback\u003cMediationBannerAd, MediationBannerAdCallback\u003e callback) {\n bannerLoader = new SampleBannerCustomEventLoader(adConfiguration, callback);\n bannerLoader.loadAd();\n }\n}\n```\n\n`SampleBannerCustomEventLoader` is responsible for the following tasks:\n\n- Loading the banner ad and invoking a\n [`MediationAdLoadCallback`](/ad-manager/mobile-ads-sdk/android/reference/com/google/android/gms/ads/mediation/MediationAdLoadCallback)\n method once loading completes.\n\n- Implementing the `MediationBannerAd` interface.\n\n- Receiving and reporting ad event callbacks to Google Mobile Ads SDK.\n\nThe optional parameter defined in the UI is\nincluded in the ad configuration. The parameter can be accessed through\n`adConfiguration.getServerParameters().getString(MediationConfiguration.CUSTOM_EVENT_SERVER_PARAMETER_FIELD)`.\nThis parameter is typically an ad unit identifier that an ad network SDK\nrequires when instantiating an ad object. \n\nJava \n\n```java\npackage com.google.ads.mediation.sample.customevent;\n\nimport com.google.android.gms.ads.mediation.Adapter;\nimport com.google.android.gms.ads.mediation.MediationBannerAdConfiguration;\nimport com.google.android.gms.ads.mediation.MediationAdLoadCallback;\nimport com.google.android.gms.ads.mediation.MediationBannerAd;\nimport com.google.android.gms.ads.mediation.MediationBannerAdCallback;\n...\n\npublic class SampleBannerCustomEventLoader extends SampleAdListener implements MediationBannerAd {\n\n /** View to contain the sample banner ad. */\n private SampleAdView sampleAdView;\n\n /** Configuration for requesting the banner ad from the third-party network. */\n private final MediationBannerAdConfiguration mediationBannerAdConfiguration;\n\n /** Callback that fires on loading success or failure. */\n private final MediationAdLoadCallback\u003cMediationBannerAd, MediationBannerAdCallback\u003e\n mediationAdLoadCallback;\n\n /** Callback for banner ad events. */\n private MediationBannerAdCallback bannerAdCallback;\n\n /** Constructor. */\n public SampleBannerCustomEventLoader(\n @NonNull MediationBannerAdConfiguration mediationBannerAdConfiguration,\n @NonNull MediationAdLoadCallback\u003cMediationBannerAd, MediationBannerAdCallback\u003e\n mediationAdLoadCallback) {\n this.mediationBannerAdConfiguration = mediationBannerAdConfiguration;\n this.mediationAdLoadCallback = mediationAdLoadCallback;\n }\n\n /** Loads a banner ad from the third-party ad network. */\n public void loadAd() {\n // All custom events have a server parameter named \"parameter\" that returns\n // back the parameter entered into the UI when defining the custom event.\n Log.i(\"BannerCustomEvent\", \"Begin loading banner ad.\");\n String serverParameter =\n mediationBannerAdConfiguration.getServerParameters().getString(\n MediationConfiguration.CUSTOM_EVENT_SERVER_PARAMETER_FIELD);\n\n Log.d(\"BannerCustomEvent\", \"Received server parameter.\");\n\n Context context = mediationBannerAdConfiguration.getContext();\n sampleAdView = new SampleAdView(context);\n\n // Assumes that the serverParameter is the ad unit of the Sample Network.\n sampleAdView.setAdUnit(serverParameter);\n AdSize size = mediationBannerAdConfiguration.getAdSize();\n\n // Internally, smart banners use constants to represent their ad size, which\n // means a call to AdSize.getHeight could return a negative value. You can\n // accommodate this by using AdSize.getHeightInPixels and\n // AdSize.getWidthInPixels instead, and then adjusting to match the device's\n // display metrics.\n int widthInPixels = size.getWidthInPixels(context);\n int heightInPixels = size.getHeightInPixels(context);\n DisplayMetrics displayMetrics = Resources.getSystem().getDisplayMetrics();\n int widthInDp = Math.round(widthInPixels / displayMetrics.density);\n int heightInDp = Math.round(heightInPixels / displayMetrics.density);\n\n sampleAdView.setSize(new SampleAdSize(widthInDp, heightInDp));\n sampleAdView.setAdListener(this);\n\n SampleAdRequest request = createSampleRequest(mediationBannerAdConfiguration);\n Log.i(\"BannerCustomEvent\", \"Start fetching banner ad.\");\n sampleAdView.fetchAd(request);\n }\n\n public SampleAdRequest createSampleRequest(\n MediationAdConfiguration mediationAdConfiguration) {\n SampleAdRequest request = new SampleAdRequest();\n request.setTestMode(mediationAdConfiguration.isTestRequest());\n request.setKeywords(mediationAdConfiguration.getMediationExtras().keySet());\n return request;\n }\n}\n```\n\nDepending on whether the ad is successfully fetched or encounters an error, you\nwould call either\n[`onSuccess()`](/ad-manager/mobile-ads-sdk/android/reference/com/google/android/gms/ads/mediation/MediationAdLoadCallback#onSuccess(MediationAdT))\nor\n[`onFailure()`](/ad-manager/mobile-ads-sdk/android/reference/com/google/android/gms/ads/mediation/MediationAdLoadCallback#onFailure(com.google.android.gms.ads.AdError)).\n`onSuccess()` is called by passing in an instance of the class that implements\n`MediationBannerAd`.\n\nTypically, these methods are implemented inside callbacks from the\nthird-party SDK your adapter implements. For this example, the Sample SDK\nhas a `SampleAdListener` with relevant callbacks: \n\nJava \n\n```java\n@Override\npublic void onAdFetchSucceeded() {\n bannerAdCallback = mediationAdLoadCallback.onSuccess(this);\n}\n\n@Override\npublic void onAdFetchFailed(SampleErrorCode errorCode) {\n mediationAdLoadCallback.onFailure(SampleCustomEventError.createSampleSdkError(errorCode));\n}\n```\n\n`MediationBannerAd` requires implementing a `View` getter method: \n\nJava \n\n```java\n@Override\n@NonNull\npublic View getView() {\n return sampleAdView;\n}\n```\n\nForward mediation events to Google Mobile Ads SDK\n\nOnce `onSuccess()` is called, the returned `MediationBannerAdCallback` object\ncan then be used by the adapter to forward presentation events from the\nthird-party SDK to Google Mobile Ads SDK. The\n`SampleBannerCustomEventLoader` class extends the `SampleAdListener` interface\nto forward callbacks from the sample ad network to Google Mobile Ads SDK.\n\nIt's important that your custom event forwards as many of these callbacks as\npossible, so that your app receives these equivalent events from the Google\nMobile Ads SDK. Here's an example of using callbacks: \n\nJava \n\n```java\n@Override\npublic void onAdFullScreen() {\n bannerAdCallback.onAdOpened();\n bannerAdCallback.reportAdClicked();\n}\n\n@Override\npublic void onAdClosed() {\n bannerAdCallback.onAdClosed();\n}\n```\n\nThis completes the custom events implementation for banner ads. The full example\nis available on\n[GitHub](//github.com/googleads/googleads-mobile-android-mediation/tree/master/Example/customevent/src/main/java/com/google/ads/mediation/sample/customevent).\nYou can use it with an ad network that is already supported or modify it to\ndisplay custom event banner ads."]]