title: Android: cannot resolve appcompat-v7 themes
body: <p>In <code>themes.xml</code>, I would like to change a theme from <code>Theme.Holo.Light.DarkActionBar</code> to <code>Theme.AppCompat.Light.DarkActionBar</code></p>
  
  <p>but I get: </p>
  
  <blockquote>
    <p>cannot resolve symbol
    '@android:style/Theme.AppCompat.Light.DarkActionBar'</p>
  </blockquote>
  
  <p>In the gradle file I added:</p>
  
  <pre><code>compile 'com.android.support:appcompat-v7:22.1.1'
  </code></pre>
  
  <p>I am using:</p>
  
  <pre><code>compileSdkVersion 22
  buildToolsVersion "22.0.1"
  </code></pre>
  
  <p>I have also run gradle's <code>clean</code> command, but nothing seems to change.</p>
  
  <p>Any ideas?</p>