title: RecyclerView don't clip item in the corner
body: <p>I want to make recyclerView round corner but seem like if the child item has background color, it will cover to the recyclerView and couldn't be clipped. Here is the design
  If I remove the background color of item, then it could be like my design. But unfortunately, sometime it has blue background</p>
  
  <p><a href="https://i.stack.imgur.com/gMvaC.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gMvaC.jpg" alt="Design"></a></p>
  
  <p>Here is what my app show
  <a href="https://i.stack.imgur.com/HPaGO.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HPaGO.png" alt="Here is what my app show"></a></p>
  
  <p>Here is my item layout</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.constraint.ConstraintLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/item_popover"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:paddingTop="@dimen/dp_8"
      android:background="@color/white"
      tools:ignore="RtlHardcoded,RtlSymmetry"
      xmlns:tools="http://schemas.android.com/tools"
      xmlns:app="http://schemas.android.com/apk/res-auto"&gt;
  
      &lt;com.jp.base.customView.AppImageView
          android:id="@+id/img_notification"
          android:paddingRight="@dimen/dp_8"
          app:srcCompat="@mipmap/ic_launcher_round"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintTop_toTopOf="parent"
          android:layout_marginStart="@dimen/dp_8"
          android:layout_marginEnd="@dimen/dp_8"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content" /&gt;
  
      &lt;android.support.v7.widget.AppCompatImageView
          android:id="@+id/img_arrow"
          app:srcCompat="@drawable/ic_keyboard_arrow_right_blue_24dp"
          app:layout_constraintTop_toTopOf="parent"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintEnd_toEndOf="parent"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content" /&gt;
  
      &lt;com.jp.base.customView.AppTextView
          android:id="@+id/tv_message"
          tools:text="Message....\nMessage"
          app:layout_constraintTop_toTopOf="parent"
          app:layout_constraintStart_toEndOf="@id/img_notification"
          app:layout_constraintEnd_toStartOf="@id/img_arrow"
          android:maxLines="5"
          android:layout_marginTop="@dimen/dp_5"
          android:textColor="@color/black"
          android:layout_width="0dp"
          android:layout_height="wrap_content" /&gt;
  
      &lt;com.jp.base.customView.AppTextView
          android:id="@+id/tv_time"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          android:layout_marginTop="@dimen/dp_8"
          android:drawablePadding="@dimen/dp_8"
          android:gravity="center_vertical"
          android:textSize="@dimen/text_small"
          app:app_leftDrawable="@drawable/ic_access_time_black_24dp"
          app:layout_constraintHorizontal_bias="0"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintEnd_toStartOf="@+id/img_arrow"
          app:layout_constraintStart_toEndOf="@id/img_notification"
          app:layout_constraintTop_toBottomOf="@+id/tv_message"
          app:layout_constraintVertical_bias="100"
          tools:text="a month ago" /&gt;
  
      &lt;View
          app:layout_constraintTop_toBottomOf="@id/tv_time"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintEnd_toEndOf="parent"
          android:layout_marginTop="@dimen/dp_8"
          android:background="@color/gray"
          android:layout_width="0dp"
          android:layout_height="0.5dp" /&gt;
  
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>
  
  <p>My RecyclerView:</p>
  
  <pre><code>&lt;android.support.v7.widget.RecyclerView
              android:id="@+id/list_notification"
              android:layout_width="0dp"
              android:layout_height="0dp"
              android:layout_marginTop="-30dp"
              android:background="@drawable/rect_bound_bottom_5dp"
              android:clipChildren="true"
              app:layout_constraintBottom_toBottomOf="parent"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintStart_toStartOf="parent"
              app:layout_constraintTop_toBottomOf="@id/tv_popup_title"
              tools:listitem="@layout/item_popover" /&gt;
  </code></pre>