title: How to remove underline from dropdown menu material design in android
body: <p>I can't seem to get rid of the black underline from <a href="https://material.io/design/components/menus.html#exposed-dropdown-menu" rel="nofollow noreferrer">Exposed Dropdown Menu</a> done according to material design guide in my android UI.  </p>
  
  <p>The dropdown looks like this:</p>
  
  <p><img src="https://i.imgur.com/jzOLv4U.png" alt=""></p>
  
  <p>I have tried setting background to null, transparent or custom shape. <code>app:boxBackgroundMode="none"</code> doesn't work either.</p>
  
  <pre><code>&lt;com.google.android.material.textfield.TextInputLayout
          android:id="@+id/spinner_age"
          style="@style/Widget.MaterialComponents.TextInputLayout.FilledBox.ExposedDropdownMenu"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:background="@drawable/bg_rounded_button"
          android:hint="Age"&gt;
  
          &lt;AutoCompleteTextView
              android:id="@+id/age_dropdown"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:background="@android:color/transparent"/&gt;
  
  &lt;/com.google.android.material.textfield.TextInputLayout&gt;
  </code></pre>
  
  <p>Ideally the dropdown would look like a button without the underline. How do I get rid of it?</p>