The In-App Purchasing API lets you sell digital content and subscriptions–such as in-game currency, expansion packs, upgrades, magazine issues and more–from within your apps. Here is an example to implement In App purchases for Amazon in Android. We have to add the following in AndroidMainfest.xml: Wehave use the following java classes to Implement this.

In-app Billing is a Google Play service that lets you sell digital content from inside your applications. You can use the service to sell a wide range of content, including downloadable content such as media files or photos, virtual content such as game levels or potions, premium services and features, and more. You can use

SharedPreferences is an interface for accessing and modifying preference data returned by getSharedPreferences(String, int). For any particular set of preferences, there is a single instance of this class that all clients share. Modifications to the preferences must go through an SharedPreferences.Editor object to ensure the preference values remain in a consistent state and control when