Error in Adding the In-app Billing Library

Question

I was doing this following these steps as mentioned in the link.

1. Copy the IInAppBillingService.aidl file to your Android project.
   (1) If you are

Answer 1

Check that you have added billing library in your build.gladle under dependencies

dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:27.1.1'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

implementation 'com.android.billingclient:billing:1.1'
}

See the last line in the above code. Implementing 'com.android.billingclient:billing:1.1' solved same problem for me