title: Custom logic for exoplayer controller
body: <p>I've managed to create a custom controller for my exoplayer.
  In this layout I placed a few buttons and some other elements that i would like to be able to control (add some events, change text, etc...).
  What class do I have to extend? How do I "link" the controller with my custom logic?
  Here's what I've done so far:</p>
  
  <pre><code>&lt;com.google.android.exoplayer2.ui.PlayerView
              android:id="@+id/player"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent"
              app:show_buffering="when_playing"
              app:controller_layout_id="@layout/customController"/&gt;
  </code></pre>
  
  <p>In customController.xml i have stuff like this:</p>
  
  <pre><code>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="350dp"
  android:layout_height="100dp"
  android:layout_gravity="bottom"
  android:orientation="vertical"&gt;
  &lt;TextView
      android:id="@+id/fileName"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Change me!"/&gt;
  </code></pre>
  
  <p>Thanks!</p>