in-app purchases for android

By,

Ningan

What is In-App Purchase?
Types of in-app purchases supported in Android
Setup of In-App Purchases in android application
Testing of In-App Billing

What is in-app purchase?

Its a service provided by google, that lets you sell digital content from inside of your application.

Examples for digital contents are: In-game currency,

application upgrade & new content of your application.

No special account or registration is required other than Google Play Developer Console account & a Google Wallet merchant account.

In-app Billing can be implemented only in applications that you publish through Google Play.

types of in-app billing

These are of two types:

1) Standard In-App Products

* These are one time billing products.

2) Subscriptions

* These are recurring or automated billing products.

in-app purchase set up

Prerequisites:

We need to have Google Play Developer Console account.
Google Wallet Merchant account to create a product list & issue refunds to users if necessary.

Installing the Google Play Billing Library:

Window> Android SDK Manager > Extras > Google Play Billing Library.

It will be installed in:

<Android SDK path>/extras/google/play_billing

The IInappBillingService.aidl file which needs to be included in the application which wants In-App Billing service.

Setting up of sample application:

Add the billing permission to AndroidManifest:

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

Create a package com.android.vending.billing in src folder & then add IInAppBillingServices.aidl file to it.
Adding utility classes to the application:

* These are some of the classes which are provided as part of billing library, to implement In-App billing easier.

* Create a package, for Example, <domain>.util & then add all the util classes which are available in TrivialDrive sample application.

Then create a ServiceConnection & bind it to IInAppBillingService.

IInAppBillingService mService;
ServiceConnection mServiceConn = new ServiceConnection() {
   @Override
   public void onServiceDisconnected(ComponentName name) {
       mService = null;
   }
   @Override
   public void onServiceConnected(ComponentName name, 
      
      IBinder service) {
       mService = IInAppBillingService.Stub.asInterface(service);
   }
};

This is done by IabHelper class in the sample project in two steps:

IabHelper mHelper;
public void onCreate(Bundle savedInstanceState) {
   String base64EncodedPublicKey;
   
   // compute your public key and store it in base64EncodedPublicKey
   mHelper = new IabHelper(this, base64EncodedPublicKey);
}

Then perform the service binding by calling startSetup on the IabHelper instance:

mHelper.startSetup(new IabHelper.OnIabSetupFinishedListener() {
   public void onIabSetupFinished(IabResult result) {
      if (!result.isSuccess()) {
         // Oh noes, there was a problem.
         Log.d(TAG, "Problem setting up In-app Billing: " + result);
      }            
         // Hooray, IAB is fully set up!  
   }
});

Send In-App Billing requests(Item purchasing) to IInAppBillingService:

Bundle buyIntentBundle = mService.getBuyIntent(3, getPackageName(),
   sku, "inapp", "bGoa+V7g/yqDXvKRqq+JTFn4uQZbPiQJo4pf9RzJ");

Note: Purchase types > "inapp" or "subs"

Handle In-App Billing response from Google Play.

Querying for purchased items:

Bundle ownedItems = mService.getPurchases(3, getPackageName(), "inapp", null);

To unbind & free your system resources, call IabHelper's dispose method when your activity gets destroyed.

@Override
public void onDestroy() {
   if (mHelper != null) mHelper.dispose();
   mHelper = null;
}

testing in-app billing

Since the google play does not allow to use developer account to directly purchase an in-app product, it provides following two ways to test the in app billing.

1) Test with your own product IDs:

* To create test account, login to developer console & then

enter a valid gmail account.

Developer console > Settings > account details > Licence Testing > test account

* Then build signed apk of your app & then distribute it to the device, where test account is the primary account.

* Finally test all purchases as it wont be charged.

2) Test with static responses:

There are 4 test product IDs, which are provided by google for testing In-App Billing early in development stage.

i) android.test.purchased

ii) android.test.cancelled

iii) android.test.refunded

iv) android.test.item_unavailable

creating new in-app product

Android in-a

By Torry Harris Business Solutions