title: Didn't find class "androidx.constraintlayout.ConstraintLayout"
body: <p>I am developing a library for Android, and this library has some activities with its layouts.</p>
  
  <p>In the layout, I have the next code</p>
  
  <pre><code>...
    &lt;android.support.constraint.ConstraintLayout
              android:layout_width="match_parent"
              android:layout_height="wrap_content"&gt;
  
              &lt;com.google.android.material.floatingactionbutton.FloatingActionButton
  ...
  </code></pre>
  
  <p>I am using Androidx.</p>
  
  <p>An I get the following error:</p>
  
  <blockquote>
    <p>Error inflating class android.support.constraint.ConstraintLayout</p>
  </blockquote>
  
  <p>The first attempt to solve this was to change<code>android.support.constraint.ConstraintLayout</code> to <code>androidx.constraintlayout.widget.ConstraintLayout</code></p>
  
  <p>But when I do this I get the following error:</p>
  
  <blockquote>
    <p>androidx.constraintlayout.widget.ConstraintLayout cannot be cast to
    androidx.constraintlayout.widget.Group</p>
  </blockquote>
  
  <p>So I try to change to <code>androidx.constraintlayout.widget.Group</code></p>
  
  <p>I get the following error:</p>
  
  <blockquote>
    <p>androidx.constraintlayout.widget.Group cannot be cast to
    android.view.ViewGroup</p>
  </blockquote>
  
  <p>I did a refactor again to androidx and then I get the following error:</p>
  
  <blockquote>
    <p>Didn't find class "androidx.constraintlayout.ConstraintLayout"</p>
  </blockquote>
  
  <p>Any idea?</p>
  
  <p>Thanks</p>