title: Pin a view to bottom of screen in BottomSheetDialog Fragment
body: <p>I've used BottomSheetDialogFragment in my project and I've designed it as below:</p>
  
  <p><a href="https://i.stack.imgur.com/DAco0.png" rel="noreferrer"><img src="https://i.stack.imgur.com/DAco0.png" alt="BottomSheetDialogFragment"></a></p>
  
  <p><strong><em>Target:</em></strong> I'm going to stick the bottom menu of BottomSheetDialog to bottom of the screen, in either mode collapse and expand.</p>
  
  <p>So in BottomSheetDialog layout, I used RelativeLayout for parent and "layout_alignParentBottom" for menu container, As below:</p>
  
  <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:id="@+id/bottomSheetContainer"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_gravity="center_horizontal"
  app:behavior_hideable="true"
  app:behavior_peekHeight="0dp"
  app:layout_behavior="android.support.design.widget.BottomSheetBehavior"
  tools:context=".MyBottomSheetDialogFragment"&gt;
  
  &lt;RelativeLayout
      android:id="@+id/topSection"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_alignParentTop="true"&gt;
      ....
  &lt;/RelativeLayout&gt;
  
  &lt;android.support.v4.widget.NestedScrollView
      android:id="@+id/descriptionContainer"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_below="@id/topSection"&gt;
      ....
  &lt;/android.support.v4.widget.NestedScrollView&gt;
  
  &lt;HorizontalScrollView
      android:id="@+id/iconsContainer"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_alignParentBottom="true"&gt;
      ....
  &lt;/HorizontalScrollView&gt;
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>But the dialogue is as follows:</p>
  
  <p><a href="https://i.stack.imgur.com/x2glF.png" rel="noreferrer"><img src="https://i.stack.imgur.com/x2glF.png" alt="BottomSheetDialog"></a></p>
  
  <p>As you can see, the bottom menu is not visible at first.</p>
  
  <p><em>Can someone help me to solve this problem?</em></p>