requestPurchase("com.example.item")

That's how simple it should be to use Android In-app Billing.

And with this library it is.

(or will be; this is a very early release)

Android Billing Library implements in-app billing's full specification and offers high-level classes to use it. Transactions are stored in a local obfuscated database which can be easily queried.

• Add this library to your project.

• Open the AndroidManifest.xml of your application and add this permission...

<uses-permission android:name="com.android.vending.BILLING" />

...and this service and receiver inside the application element:

<service android:name="net.robotmedia.billing.BillingService" />
<receiver android:name="net.robotmedia.billing.BillingReceiver">
	<intent-filter>
		<action android:name="com.android.vending.billing.IN_APP_NOTIFY" />
		<action android:name="com.android.vending.billing.RESPONSE_CODE" />
		<action android:name="com.android.vending.billing.PURCHASE_STATE_CHANGED" />
	</intent-filter>
</receiver>

• Subclass AbstractBillingActivity in the activity in which you want to use in-app billing. Or use BillingController if you need finer-grain control.

That's it!

AbstractBillingActivity is an abstract activity that provides default integration with in-app billing. It is useful to get acquainted with the library, or for very simple applications. For more flexibility use BillingController instead.

When started your AbstractBillingActivity subclass will check if in-app billing is supported, followed by a call to onBillingChecked(boolean), which has to be implemented by the subclass.

Additionally, the first your AbstractBillingActivity subclass runs it will attempt to restore all transactions. This is necessary in case the user has previously installed the app and made purchases. Existing transactions will generate calls to onPurchaseExecuted(String), onPurchaseCancelled(String) and onPurchaseRefunded(String) accordingly, all of which have to be implemented by the subclass.

Starting a purchase is as simple as calling requestPurchase(String). AbstractBillingActivity will start the Android Market intent automatically and onPurchase{State}(String) will be called after the transaction is confirmed.

BillingController provides high-level functions to interact with the Billing service and to query an obfuscated local transaction database.

Since most billing functions are asynchronous, BillingController notifies all registered IBillingObserver of the responses. Additionally, BillingController requires a BillingController.IConfiguration instance from which the public key required to validate signed messages and a salt to obfuscate transactions are obtained.

This library is a very early release and it should not be used as production code.

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Copyright 2011 Robot Media SL. All rights reserved.

Android Billing Library is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Android Billing Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser Public License for more details.

You should have received a copy of the GNU Lesser Public License along with Android Billing Library. If not, see http://www.gnu.org/licenses/.