EU User Consent
As of September 30, 2015, an app must inform and receive consent from users within European Union countries about any data collection, sharing, and usage that may take place within the app. This is required in order to comply with Google's EU user consent policy when using Google services such as Google Analytics or AdMob.
Google has provided the www.cookiechoices.org site that contains more information and suggests text that may be appropriate for the consent message that you present to your users. See the section titled "What do I put in my consent message?" which currently suggests the following text might be appropriate for an app:
We use device identifiers to personalise content and ads, to provide social media features and to analyse our traffic. We also share such identifiers and other information from your device with our social media, advertising and analytics partners. See details
Note that this is just a broad example, and may not reflect what is needed for your app, or an app that uses the minimum Google services. You will need to determine the appropriate notice text for your app based on the services it uses and any additional information you might collect.
Note also that Google's example includes a link in order to provide the user with more information. You will need to determine an appropriate web page to link to if you choose to include a link in your notice.
Please see www.cookiechoices.org for more information.
If your app does not retrieve or store any identifying information, and only collects anonymous data, you may be able to assume implied consent. Implied consent means that you only need to inform the user, and don't require the user's acceptance in order to proceed. This is the kind of consent that is required for the use of Google Services in Andromo such as Google Analytics and AdMob. With implied consent, you can use the Launch Notice feature on the App Info tab to inform the user.
However, if you've configured your app to collect additional user information, for example through a Website or HTML Archive activity, then your app may require explicit consent from the users. Explicit consent means the user must agree to the data collection in order to use the app. If your app requires explicit consent, you should notify the user in your license agreement, and use the License Agreement feature on the App Info tab to ask the user for consent the first time they launch the app.