title: Why are there two build.gradle files in an Android Studio project?
body: <p>After having imported an Eclipse project into Android Studio, I see two <code>build.gradle</code> files:</p>
  
  <pre><code>1 - &lt;PROJECT_ROOT&gt;\build.gradle
  2 - &lt;PROJECT_ROOT&gt;\app\build.gradle
  </code></pre>
  
  <p>The first version is shorter, the second version contains definitions for <code>compileSdkVersion</code>, etc.</p>
  
  <p>What is the purpose behind having two separate files?  Are there separate build tasks?</p>