title: Android Studio does not detect .aidl files
body: <p>I have found a sample from the Internet (<a href="https://github.com/manishkpr/Android-AIDL-Example">https://github.com/manishkpr/Android-AIDL-Example</a>) and ran on Android Studio and it worked fine.</p>
  
  <p>But now when I am trying to recreate the project, the Android Studio fails to recognize the 
  .aidl file no matter where I place it.
  Can anybody tell me what is the right location to place .aidl files in Android Studio?</p>
  
  <p>p.s. I have added the below code to build.gradle and place the .aidl file in the java directory, but failed to get it work.</p>
  
  <pre><code>sourceSets {
  main {
      aidl.srcDirs = ['src/main/java']
  }
  </code></pre>