title: cannot resolve symbol AppCompat
body: <p>I am trying to add a Splash Screen to an existing mobile app for Android using Android Studio. From everything I have researched, I need to be using AppCompat to do this, but each time I try to add it to my styles.xml file, Android Studio tells me "cannot resolve symbol "AppCompat"". Is there somewhere else I should be adding this prior to the styles page in order to have code accept it? My code is below.</p>
  
  <p>Styles.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;resources&gt;
  
      &lt;style name="AppTheme" parent="AppCompat"&gt;
          &lt;item name="android:colorPrimary"&gt;&lt;/item&gt;
      &lt;/style&gt;
  
      &lt;style name="SplashTheme" parent="Theme.AppTheme"&gt;
          &lt;item name="android:windowBackground"&gt;@drawable/background&lt;/item&gt;
      &lt;/style&gt;
  
  &lt;/resources&gt;
  </code></pre>
  
  <p>I tried adding it to my AndroidManifest.xml file to no effect, I receive the error "Unknown resource type" in that file.</p>
  
  <p>When I attempted to change my Main file to:
  "public class Snake extends AppCompatActivity"
  I receive the "Cannot resolve symbol" error again. </p>
  
  <p>I feel like the guides I have read are leaving out some crucial, yet shockingly obvious, step that most people familiar with Android would know quite well. Regretfully, I am still quite new to Android and trying to learn.</p>