title: Recyclerview cannot be scrolled?
body: <p>I have this screen.</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="vertical" android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:padding="5dp"&gt;
  
      &lt;RelativeLayout
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"&gt;
  
          &lt;android.support.v7.widget.RecyclerView
              android:id="@+id/my_recycler_view"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:scrollbars="vertical"/&gt;
  
      &lt;/RelativeLayout&gt;
  
      &lt;Button
          android:id="@+id/btn_sync"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_gravity="center_horizontal"
          android:onClick="DoUpload"
          android:text="Sync with server"
          /&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>It looks like this (which is OK):</p>
  
  <p><a href="https://i.stack.imgur.com/PuUmq.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PuUmq.png" alt="enter image description here"></a></p>
  
  <p>So I add more datas, now it looks like this:</p>
  
  <p><a href="https://i.stack.imgur.com/4nRds.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4nRds.png" alt="enter image description here"></a></p>
  
  <p>The RecyclerView cannot be scrolled, and the button is hidden. How to fix this?</p>