title: CardView for Android 9.0 has space black blank, how to remove the black space
body: <p>CardView for Android has black spaces, how to remove it. i need help.
  this is java or android problem.</p>
  
  <p><a href="https://i.stack.imgur.com/QryIc.jpg" rel="nofollow noreferrer">enter image description here</a></p>
  
  <pre><code>&lt;android.support.v7.widget.CardView
                  android:id="@+id/cv_result_knowledge"
                  android:layout_width="match_parent"
                  android:layout_height="wrap_content"
                  android:layout_below="@+id/ll_result_header"
                  android:clickable="true"
                  android:foreground="?android:attr/selectableItemBackground"
                  android:visibility="gone"
                  app:cardBackgroundColor="@color/black_transparent40"
                  app:cardCornerRadius="@dimen/d12"
                  app:cardElevation="@dimen/d1"
                  app:cardPreventCornerOverlap="false"
                  app:cardUseCompatPadding="true"&gt;
                  &lt;RelativeLayout
                      android:layout_width="match_parent"
                      android:layout_height="wrap_content"
                      android:layout_marginBottom="@dimen/d10"
                      android:layout_marginTop="@dimen/d2"&gt;
  
  
  
                  &lt;/RelativeLayout&gt;
              &lt;/android.support.v7.widget.CardView&gt;
  </code></pre>