use InAppBillingService in Android Studio

This is for those people who use Android Studio(AS as short) to develop. If you are using other IDE and also need help, you can leave comments to seek help.

First, if you aren't use AS to create new project with Gradle project structure, you can ignore this article. 

Above screenshot show the correct directory structure to put the IInAppBillingService.aidl.

The default directory structure does not have aidl . You need to create it by yourself. After that, you just need to rebuild the project, then you can use this service just like the sample TrivalDriver.

P.S. I am still a newbie in Android development.

P.S^2 母語是中文, 所以大家都可以用中文問題. I can understand Chinese, I am just too lazy to type Chinese =3=