Android Tutorial Android In-App Billing v3 Tutorial

New version: GooglePlayBilling - In App Purchases

This tutorial covers the new API for in-app billing provided by Google.

The main differences between v3 and the previous version are:
- (v3) Is easier to implement.
- Supports managed products and subscriptions. Unmanaged products are not supported.
- Includes a method to retrieve all purchased items. This means that you do not need to manage the items yourself.
- Allows you to "consume" managed products. For example if the user has bought a game add-on and then used it, the app consumes the product allowing the user to purchase the add-on again.

The official documentation is available here: In-app Billing Version 3 | Android Developers

Implementing in-app billing in your application

The first step is to upload a draft APK to Google developer console. Note that you should use a private signing key to sign the app.

Under Services & APIs you will find your license key. This key is also required for in-app billing:


You should also add at least one item to the "In-app Products" list. The item's type should be Managed Product or Subscription.

Basic4android code

The first step is to initialize a BillingManager3 object:
Sub Process_Globals
   Dim manager As BillingManager3
   Private key As String = "MIIBIjANBgkqhkiG9w0BAQEFAA..."
End Sub

Sub Globals

End Sub

Sub Activity_Create(FirstTime As Boolean)
   If FirstTime Then
      manager.Initialize("manager", key)
      manager.DebugLogging = True
   End If
End Sub

Sub Manager_BillingSupported (Supported As Boolean, Message As String)
   Log(Supported & ", " & Message)
   Log("Subscriptions supported: " & manager.SubscriptionsSupported)
End Sub

The BillingSupported event will be raised with the result. Note that all of the billing related actions happen in the background and raise events when the action is completed.

Calling manager.GetOwnedProducts will raise the OwnedProducts event. The OwnedProducts event includes a Map that holds the user current purchases. The keys in the map are the products ids (or Skus) and the values are objects of type Purchase. These objects include more information about the purchase and are required for other actions, such as consuming a purchase.

Sub manager_OwnedProducts (Success As Boolean, purchases As Map)
   If Success Then
      For Each p As Purchase In purchases.Values
         Log(p.ProductId & ", Purchased? " & (p.PurchaseState = p.STATE_PURCHASED))
   End If
End Sub

Purchasing a product is done by calling: manager.RequestPayment. The user will be asked to approve the payment. The PurchaseCompleted event will be raised when the operation completes.

Note that managed products can only be purchased once. Only after you call ConsumeProduct will the user be able to purchase the same item again.

Consuming purchased products is done by calling manager.ConsumeProduct.
For example:
If ownedProducts.ContainsKey("test2") Then
End If

The ProductConsumed event will be raised.

- See this tutorial for more information about the possible testing options: Testing In-app Billing | Android Developers
- If you get a "signature verification error" when trying to make a purchase then you should make sure that the licensing key is correct. If it is correct then try to upload a new APK.
- It is recommended to use a process global variable to hold the key. This way it will be obfuscated when you compile in obfuscated mode.
- Only one background request can run at a time.

The library is available here:
Last edited:


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question, if I have an app like ebay with hundreds of suppliers, do they have to upload their products to In-App billing through my app ?