Question

I’m attempting to make a free app upgradable to the “paid” version using in-app billing. I used code from this tutorial to handle the billing as the one on the official developer
site is too complex and messy to follow for a simple flow like mine.

My code to do the upgrade works fine.

The problem comes when I try to add something to check if the user has already purchased but has lost their purchase data either by reinstalling or by clearing the data (I don’t care which).

On app startup I check for a flag that’s set after the first run. If that flag isn’t there, the user is shown a dialog warning them that the app will check for previous purchases, and when they click ok, the restoreTransactionInformation method is called. This then causes the application to force close.

Because in-app billing doesn’t work when debugging or on the emulator, I have to publish a signed version of the app each time I want to try the code. I have no way of knowing why the application exits when I try to make the restoreTransactionInformation request. Does anyone have a clue how I can diagnose it, or what might be causing my app to die? Or a working example of how to use the restoreTransactionInformation method?

EDIT: So it looks like the RESTORE_TRANSACTIONS request is getting a correct response, and returning details of my test purchase. Unfortunately before it can do anything with it, the app is forced closed. Here’s a logcat (without obfuscated code) of what happens right after market responds to the RESTORE_TRANSACTIONS request:

I/BillingService( 6484): confirmTransaction()
D/Finsky  ( 1884): [7] MarketBillingService.getPreferredAccount: com.hippypkg: Account from first account.
I/BillingService( 6484): current request is:**********
I/BillingService( 6484): RESTORE_TRANSACTIONS Sync Response code: RESULT_OK
D/WindowManagerImpl( 6484): finishRemoveViewLocked, mViews[0]: com.android.internal.policy.impl.PhoneWindow$DecorView@**********
W/InputManagerService( 1381): [unbindCurrentClientLocked] Disable input method client.
W/InputManagerService( 1381): [startInputLocked] Enable input method client.
D/NativeCrypto( 1884): returned from sslSelect() with result 1, error code 2
D/Finsky  ( 1884): [1] MarketBillingService.sendResponseCode: Sending response RESULT_OK for request ********** to com.hippypkg.
I/BillingService( 6484): Received action: com.android.vending.billing.PURCHASE_STATE_CHANGED
I/BillingService( 6484): purchaseStateChanged got signedData: {"nonce":**********,"orders":[{"orderId":"**********","packageName":"com.hippypkg","productId":"hippy_upgrade_free_to_full","purchaseTime":1331476540000,"purchaseState":0}]}
I/BillingService( 6484): purchaseStateChanged got signature: **********==
I/BillingService( 6484): signedData: {"nonce":**********,"orders":[{"orderId":"**********","packageName":"com.hippypkg","productId":"hippy_upgrade_free_to_full","purchaseTime":1331476540000,"purchaseState":0}]}
I/BillingService( 6484): signature: **********==
I/BillingService( 6484): confirmTransaction()
I/BillingService( 6484): makerequestbundle success
I/BillingService( 6484): putstringarray success
D/Finsky  ( 1884): [24] MarketBillingService.getPreferredAccount: com.hippypkg: Account from first account.
D/AndroidRuntime( 6484): Shutting down VM
W/dalvikvm( 6484): threadid=1: thread exiting with uncaught exception (group=0x4001d5a0)
E/AndroidRuntime( 6484): FATAL EXCEPTION: main
E/AndroidRuntime( 6484): java.lang.RuntimeException: Unable to start receiver com.hippypkg.BillingReceiver: java.lang.NullPointerException
E/AndroidRuntime( 6484):    at android.app.ActivityThread.handleReceiver(ActivityThread.java:2144)
E/AndroidRuntime( 6484):    at android.app.ActivityThread.access$2400(ActivityThread.java:135)
E/AndroidRuntime( 6484):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1114)
E/AndroidRuntime( 6484):    at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime( 6484):    at android.os.Looper.loop(Looper.java:150)
E/AndroidRuntime( 6484):    at android.app.ActivityThread.main(ActivityThread.java:4385)
E/AndroidRuntime( 6484):    at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime( 6484):    at java.lang.reflect.Method.invoke(Method.java:507)
E/AndroidRuntime( 6484):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
E/AndroidRuntime( 6484):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
E/AndroidRuntime( 6484):    at dalvik.system.NativeStart.main(Native Method)
E/AndroidRuntime( 6484): Caused by: java.lang.NullPointerException
E/AndroidRuntime( 6484):    at android.os.Parcel.readException(Parcel.java:1328)
E/AndroidRuntime( 6484):    at android.os.Parcel.readException(Parcel.java:1276)
E/AndroidRuntime( 6484):    at com.android.vending.billing.IMarketBillingService$Stub$Proxy.sendBillingRequest(IMarketBillingService.java:100)
E/AndroidRuntime( 6484):    at com.hippypkg.BillingHelper.confirmTransaction(BillingHelper.java:152)
E/AndroidRuntime( 6484):    at com.hippypkg.BillingHelper.verifyPurchase(BillingHelper.java:250)
E/AndroidRuntime( 6484):    at com.hippypkg.BillingReceiver.purchaseStateChanged(BillingReceiver.java:41)
E/AndroidRuntime( 6484):    at com.hippypkg.BillingReceiver.onReceive(BillingReceiver.java:23)
E/AndroidRuntime( 6484):    at android.app.ActivityThread.handleReceiver(ActivityThread.java:2103)
E/AndroidRuntime( 6484):    ... 10 more
W/ActivityManager( 1381):   Force finishing activity com.hippypkg/.Hippy

Answer 1

So I finally managed to figure it out.

If you look at the Google Docs for the In App Billing Overview, it states that:

The RESTORE_TRANSACTIONS request type also triggers a PURCHASE_STATE_CHANGED broadcast intent, which contains the same type of transaction information that is sent during a purchase request, although you do not need to respond to this intent with a CONFIRM_NOTIFICATIONS message.

In a normal purchase-confirmTransaction cycle, when you request to purchase an In App Billing product, google sends back a JSON with a bunch of fields. One of these fields is ‘notification_id’. When google sends a PURCHASE_STATE_CHANGED intent, it expects a CONFIRM_NOTIFICATIONS response from the app, with a bundle containing a bunch of info, including the notification_id’s. All well and good here.

The problem starts when you get a PURCHASE_STATE_CHANGED from Google for a RESTORE_TRANSACTIONS request from the app. This JSON does not contain notificaion_id fields. The library still responds with a CONFIRM_NOTIFICATIONS, adding the notification_id array to the bundle, which, in this case, is null. That’s what causes the NullPointerException.

Solution:
I modified the BillingHelper.java class by adding a boolean to track when the user makes a normal purchase, and when he wants to restoreTransactions.
If it’s a restoreTransactions request, I send a message back to the handler and skip the confirmNotifications step.

EDIT:
The code for the above fix is in BillingHelper.java
I am using a boolean flag to track whether the user made a RESTORE_TRANSACTIONS call (isRestoreTransactions).

In BillingHelper.java’s ‘verifyPurchase’ method, I changed the code as follows:

protected static void verifyPurchase(String signedData, String signature) {
        ArrayList<VerifiedPurchase> purchases = BillingSecurity.verifyPurchase(signedData, signature);

        if(isRestoreTransaction)
        {
            /*
            *
            *Add some logic to retrieve the restored purchase product ID's from the 'purchases' array
            *
            */

            //Set the boolean to false
            isRestoreTranscation = false;

            //Send a message to the handler, informing it that purchases were restored
            if(mCompletedHandler != null){
                mCompletedHandler.sendEmptyMessage(0);
            } else {
                Log.e(TAG, "verifyPurchase error. Handler not instantiated. Have you called setCompletedHandler()?");
            }
        }
        else
        {
            /*
            *......
            *......
            *......
            *Original method body here
            *......
            *......
            *......
            */
        }
    }