Creating an AIDL file

an .aidl file is a barebone description of set of API's server exposes

1. Enable build feature in your build.gradle.

   buildFeatures {
    aidl = true
   }

2. Create a new AIDL file using File -> New -> AIDL -> AIDL File

3. Let's name it ICalculator.aidl

4. Declare aidl methods:

    interface IExampleAidlInterface {
        int add(int a, int b);
    }