Android In-app Billing and Proguard (Unknown Source)

Question

I am using the In-app Billing service of Google and Proguard. The configuration file that I am using as a Proguard is the one in .../sdk/tools/proguard/proguard-android.txt

As Google says here: http://developer.android.com/google/play/billing/billing_best_practices.html I added the following line in the configuration file:

-keep class com.android.vending.billing.**

I am using the updated files of IAB from Google as well: https://code.google.com/p/marketbilling/source/detail?r=7ec85a9b619fc5f85023bc8125e7e6b1ab4dd69f

The problem is that sometimes, users report random crashes with this stacktrace:

E/AndroidRuntime: FATAL EXCEPTION: Thread-455
java.lang.NullPointerException
    at com.xx.xxxx.util.IabHelper.startSetup(Unknown Source)
    at com.xx.xxxx.util.IabHelper$2.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:856)

It also happened in my device (just opening the app) but only happened once to me today.

And I am not sure if it is problems of Google files (of IAB) or something is missing in the Proguard configuration file.

Answer 1

Adding the following string

-keep class com.android.vending.billing.**

to ProGuard configuration tells him to not to obfuscate that package.

Exception comes from com.xx.xxxx.util.IabHelper, so you can try to add something like

-keep class com.xx.xxxx.util.IabHelper.**

to keep your package as it was without ProGuard.

Answer 2

Your proguard configuration is correct. I even allow to obfuscate generated com.android.vending.billing.IInAppBillingService in my app and everything works just fine.

Regarding IabHelper class. I would not suggest to use it "as is". Firstly, it is proven to be buggy. Secondly, it can be hacked by automatic tools even when obfuscated. I suggest to write your own class based on IabHelper and write junit tests for it. This is what I did for my project too.

Answer 3

This line in IabHelpers startSetup()

mContext.getPackageManager()
                .queryIntentServices(serviceIntent, 0);

Can sometimes return null, so when checking if the list is empty you get the nullpointer.

I simply modified it to check for null before doing anything else;

List<ResolveInfo> queryIntentServices = mContext.getPackageManager()
            .queryIntentServices(serviceIntent, 0);
    if (queryIntentServices != null && !queryIntentServices.isEmpty()) {
        // service available to handle that Intent
        mContext.bindService(serviceIntent, mServiceConn,
                Context.BIND_AUTO_CREATE);
    }else ...