Android In-App Billing, missing purchases

Question

I am using Google's In-App Billing for my Android app.

I used the IabHelper class from Google's how to, as their billing seems extremely complicated.

My issue is I want to know if the purchase is successful or not. I think I'm following the process correctly, but in my logs I see a lot of users that get the upgrade, but whose purchase never shows up in my Google Play payments account. (i.e. they get the upgrade for free).

I'm logging the GP order ids, sometimes its a number like,

GPA.1234-5678-9123-1234

But sometimes its like,

1234567891234.1234567891234

Normally I think its the non GPA orders that don't get charged.

Also I think you can put an order through, then cancel it, and still get the upgrade?

How do you ensure the user really paid?

Code:

IabHelper.OnIabPurchaseFinishedListener mPurchaseFinishedListener = new IabHelper.OnIabPurchaseFinishedListener() {
    public void onIabPurchaseFinished(IabResult result, final Purchase purchase) {
        if (result.isFailure()) {
            showMessage("Google Billing Purchase Error");                   
            return;
        } else if (purchase.getSku().equals(sku)) {
            IabHelper.QueryInventoryFinishedListener mReceivedInventoryListener = new IabHelper.QueryInventoryFinishedListener() {
                public void onQueryInventoryFinished(IabResult result, Inventory inventory) {
                    if (result.isFailure()) {
                        showMessage("Google Billing Error");
                        return;
                    } else {
                        if (inventory.hasPurchase(sku)) {
                            showMessage("Thank you for upgrading");
                            grantUpgrade();
                            // ** This line gets call, but no payment occurs.
                        }
                    }
                }
            };
            mHelper.queryInventoryAsync(mReceivedInventoryListener);
        }
    }
};
mHelper.launchPurchaseFlow(this, sku, 10001, mPurchaseFinishedListener, "");

*** updated to check "inventory.hasPurchase(sku)" but still see users who get the upgrade but don't pay.

** maybe the users are using Freedom hack? Anyway to prevent this?

Answer 1

 if (result.isFailure()) {
    //If the user aborts or any other problems it will jump here 
  }
  else {
    //The user purchased some item, check out which it is 
    mIsPremium = inventory.hasPurchase(SKU_ANY_ITEM);        
  }

So concerning your question, this code already verify whether the user really purchased the item !

Answer 2

Purchase premiumPurchase = inventory.getPurchase(SKU);

boolean mIsPremium = (premiumPurchase != null 
           && verifyDeveloperPayload(premiumPurchase));

if(mIsPremium){
    ...
}

Answer 3

The Google Play Store keeps track of purchases for you, so you shouldn't assume that just because a purchase was successful, the item will stay purchased. It's possible for a user to get a refund for a purchase. For this reason, you need to query the user's inventory every time you launch and adjust your grants appropriately. You would need to do this check anyways in order to support users that expect to have the grant when they switch to a new device or uninstall/reinstall the app.