Google's Live Advertising ID
Google's Live Advertising ID is a user-specific resettable ID for advertising. The ID is provided specifically for Google Play services. According to Developer Android, Google’s Live Advertising ID lets users have better controls and provides developers with a simple, standard system to continue to monetize user apps. Advertising ID is an anonymous identifier for advertising. Users are able to reset their identifier or opt out of interest-based ads within Google Play apps. The advertising ID is accessible through a straightforward API for user app implementation.
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Using the Advertising ID:
The advertising ID is a unique but user-resettable string identifier that lets ad networks and other apps anonymously identify a user. The user's advertising ID is made available to apps through APIs provided in Google Play services.
Users can reset their advertising ID at any time, right from the Ads section of the Google Settings app on their devices. From the same app, users can also opt-out of targeted advertising based on the advertising ID by setting the appropriate ad tracking preference. When the user opts-out of targeted ads, this ad tracking preference is made available to apps through a Google Play services API.
Apps making use of the advertising ID must check for and respect the user's ad tracking preference. Also please note that any use of the advertising ID must abide by the terms of the Google Play Developer Content Policies.
Format of the Advertising ID
Google Play services APIs expose the user's advertising ID as a string format of UUID, with values similar to this:
“38400000-8cf0-11bd-b23e-10b96e40000dâ€
Requirements
The advertising ID APIs are supported in Google Play services 4.0+
Support for the advertising ID on specific devices is based on their installed versions of Google Play services
Obtaining the user's advertising ID and ad tracking preference
If you want to use the advertising ID in your app, you must first install the Google Play services SDK. As noted in the requirements above, you should install the SDK for Google Play services 4.0 or higher if you will develop using the advertising ID APIs. For information about how to get started, see Set Up Google Play services.
The advertising ID APIs are available in the com.google.android.gms.ads.identifier package in the Google Play Services library. To obtain the user's advertising ID and tracking preference, call the methodgetAdvertisingIdInfo(), which returns an AdvertisingIdClient.Info encapsulating the user's current Advertising ID and tracking preference.
*Android Developers