Can't build IMarketBillingService.aidl for inApp purchase

I try to import com.android.vending.billing.IMarketBillingService. But I got the error:

The import com.android.vending.billing.IMarketBillingService cannot be resolved.

I have got another project where I do exactly the same thing and it works perfectly. I copied the files I need for in-app purchase to the new project. That means the data have to be correct. (I replaced the package name) I check multiple times wether I forgot a class. A few days ago I copied the files for a colleague and it works as well.

I tried cleaning and freshing the project as well.

Where do I put AIDL files?

Simply save your . aidl file in your project's src/ directory and when you build your application, the SDK tools generate the IBinder interface file in your project's gen/ directory.

I fixed this by unchecking all the builders on the project properties, hit OK, then check them all again and hit OK. Thanks a lot, Google!