title: Why are there 2 different ComponentActivity classes?
body: <p>I'm trying to handle back button presses in my fragments by registering an <code>OnBackPressedCallback</code> via <code>addOnBackPressedCallback</code> to receive <code>onBackPressed()</code> callbacks without needing to override the method in your activity (described <a href="https://developer.android.com/jetpack/androidx/releases/activity" rel="noreferrer">Nov 5, 2018 release notes for androidx.activity</a>)</p>
  
  <p>If you look at the <a href="https://developer.android.com/reference/androidx/appcompat/app/AppCompatActivity" rel="noreferrer">AppCompatActivity Docs</a>, it claims <code>AppCompatActivity</code> extends from <code>androidx.activity.ComponentActivity</code>.</p>
  
  <p>The problem I'm running into is, in my codebase, <code>AppCompatActivity</code> extends from <code>androidx.core.app.ComponentActivity</code> (doesn't have <code>addOnBackPressedCallback()</code>) instead of <code>androidx.activity.ComponentActivity</code> (has <code>addOnBackPressedCallback()</code>).</p>
  
  <p>My Dependency Versions</p>
  
  <pre><code>implementation "androidx.core:core-ktx:1.0.1"
  implementation "androidx.appcompat:appcompat:1.0.2"
  implementation "androidx.activity:activity-ktx:1.0.0-alpha04"
  </code></pre>
  
  <p>Can anybody else reproduce this issue? Am I doing something wrong?</p>