title: add libraries external in Android Studio
body: <p>I have a question, </p>
  
  <p>¿ What's the difference between <strong>compile project(':library/materialtabs')</strong> and <strong>compile 'it.neokree:MaterialTabs:0.11'</strong> ?.</p>
  
  <p>Because with the first option I have the following issue:</p>
  
  <pre><code>&lt;it.neokree.materialtabs.MaterialTabHost
      android:id="@+id/tabHost_main"
      android:layout_width="match_parent"
      android:layout_height="45dp"
      app:primaryColor="@color/white"
      app:accentColor="#333333"
      app:hasIcons="true"
      app:iconColor="#ffffff" /&gt;  
  </code></pre>
  
  <p>The following classes could not be instantiated:  it.neokree.materialtabs.MaterialTabHost , 
  but I use the other option  the issue is solved.</p>