Google Play services offers a standard authorization flow for all Google APIs and all components of Google Play services. In addition, you can leverage the authorization portion of the Google Play services SDK to gain authorization to services that are not yet supported in the Google Play services platform by using the access token to manually make API requests or using a client library provided by the service provider.

Deprecated Google Cloud Messaging for Android (GCM) is a service that allows you to send data from your server to your users' Android-powered device, and also to receive messages from devices on the same connection. The GCM service handles all aspects of queueing of messages and delivery to the target Android application running on the target device. GCM is completely free no matter how big your messaging needs are, and there are no quotas.

Make your games social with Google Play game services. Add achievements, leaderboards, real-time multiplayer, and other popular features using the Google Play game services SDK. Let players sign in using their Google+ identities and share their gaming experience with friends. Visit developers.google.com/games/services for more information about integrating game services into your app.

The location APIs make it easy for you to build location-aware applications, without needing to focus on the details of the underlying location technology. They also let you minimize power consumption by using all of the capabilities of the device hardware.

Allow your users explore the world with rich maps provided by Google. Identify locations with custom markers, augment the map data with image overlays, embed one or more maps as fragments, and much more.

Google Play services powers a broad set of SDKs on Android to help you build your app, enhance privacy and security, engage users, and grow your business. These SDKs are unique in that they only require a thin client library to be included in your app, as shown in figure 1. At runtime, the client library communicates with the bulk of the SDK's implementation and footprint in Google Play services.

Google Tag Manager enables developers to change configuration values in their mobile applications using the Google Tag Manager interface without having to rebuild and resubmit application binaries to app marketplaces. This is useful for managing any configuration values or flags in your application that you may need to change in the future, including: * Various UI settings and display strings * Sizes, locations, or types of ads served in your application * Game settings Configuration values may also be evaluated at runtime using rules, enabling dynamic configurations such as: * Using screen size to determine ad banner size * Using language and location to configure UI flags Google TagManager also enables the dynamic implementation of tracking tags and pixels in applications. Developers can push important events into a data layer and decide later which tracking tags or pixels should be fired. TagManager currently supports the following tags: * Google Mobile App Analytics * Custom Function Call tag

The Android platform provides a framework API that applications can use to interact with the underlying Android system. The framework API consists of: A core set of packages and classes. A set of permissions that applications can request, as well as permission enforcements included in the system

The Google Analytics SDK for Android makes it easy for native Android developers to collect user engagement data from their applications. Developers can then use the Google Analytics reports to measure: The number of active users are using their applications. From where in the world the application is being used. Adoption and usage of specific features. Crashes and exceptions. In-app purchases and transactions. And many other useful metrics... The Google Analytics SDK also gives you the tools to monitor the success of mobile marketing campaigns. Connect user interactions with paid ads, Google Play downloads, and subsequent in-app usage and Ecommerce transactions. Google Analytics provides a powerful platform to measure and optimize all of your application marketing efforts.

Gson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of.