title: Android studio can`t find aidl import
body: <p>I'm importing the app CSipsimple as a library within the app called Conversations. I have followed the accepted answer from <a href="https://stackoverflow.com/questions/16588064/how-do-i-add-a-library-project-to-the-android-studio?rq=1">here</a> but when i try sync gradle files i get the errors:</p>
  
  <pre><code>C:....gabotel\libs\CSipSimple\app\src\main\aidl\com\csipsimple\api\ISipConfiguration.aidl
  
  Error:(25) couldn't find import for class com.csipsimple.api.SipProfile
  </code></pre>
  
  <p>And </p>
  
  <pre><code>C:...gabotel\libs\CSipSimple\app\src\main\aidl\com\csipsimple\api\ISipService.aidl
  
  Error:(25) couldn't find import for class com.csipsimple.api.SipProfileState
  Error:(26) couldn't find import for class com.csipsimple.api.SipCallSession
  Error:(27) couldn't find import for class com.csipsimple.api.MediaState
  </code></pre>
  
  <p>All of those classes have separate .aidl files and are declared as parcelable. For instance sipprofile:</p>
  
  <pre><code>package com.csipsimple.api;
  parcelable SipProfile;
  </code></pre>
  
  <p>But the problem remains.</p>
  
  <p>I have read <a href="https://stackoverflow.com/questions/27138924/android-aidl-compile-error-couldnt-find-import-for-class">here</a> in the accepted answer that the solution involves modify the  base_rules.mk file, but i can`t find it.</p>
  
  <p>Any ideas?</p>
  
  <p>The library gradle, just in case, is:</p>
  
  <pre><code>// Top-level build file where you can add configuration options common to all sub-projects/modules.
  buildscript {
      repositories {
          jcenter()
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:1.0.0'
      }
  }
  
  allprojects {
      repositories {
          jcenter()
      }
  }
  
  apply plugin: 'com.android.library'
  
  dependencies {
      compile 'com.android.support:support-v4:21.0.3'
  }
  
  android {
      compileSdkVersion 21
      buildToolsVersion "21.1.2"
  
      defaultConfig {
          minSdkVersion 14
          targetSdkVersion 21
      }
  
      sourceSets {
          main {
              manifest.srcFile 'app/src/main/AndroidManifest.xml'
              java.srcDirs = ['app/src']
              resources.srcDirs = ['app/src']
              aidl.srcDirs = ['app/src']
              renderscript.srcDirs = ['app/src']
              res.srcDirs = ['app/res']
              assets.srcDirs = ['app/assets']
          }
      }
  }
  </code></pre>