title: Android ScrollView fillViewport not working
body: <p>I have a simple layout with a name on the top, and a button which I want to be at the bottom of the screen, or beyond that in case I add more items.</p>
  
  <p>So I am using a ScrollView with a LinearLayout as follows:</p>
  
  <pre><code>&lt;ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:background="@android:color/white"
  android:fillViewport="true"
  android:focusableInTouchMode="true"
  android:paddingBottom="@dimen/activity_vertical_margin"
  android:paddingLeft="@dimen/activity_horizontal_margin"
  android:paddingRight="@dimen/activity_horizontal_margin"
  tools:context=".ItemDetailActivity" &gt;
  
  &lt;LinearLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="vertical" &gt;
  
      &lt;!-- Name --&gt;
  
      &lt;RelativeLayout
          android:id="@+id/top_content"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:layout_gravity="top" &gt;
  
          &lt;TextView
              android:id="@+id/name_label"
              style="@style/Header_Label_TextView"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:text="@string/name" /&gt;
  
          &lt;TextView
              android:id="@+id/name_value"
              style="@style/Value_Label_TextView"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:layout_below="@id/name_label" /&gt;
      &lt;/RelativeLayout&gt;
  
      &lt;!-- button --&gt;
  
      &lt;RelativeLayout
          android:id="@+id/ButtonLayout"
          android:layout_width="fill_parent"
          android:layout_height="wrap_content"
          android:layout_gravity="bottom" &gt;
  
          &lt;Button
              android:id="@+id/add_button"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:layout_marginTop="10sp"
              android:onClick="editItem"
              android:text="@string/button_edit" /&gt;
      &lt;/RelativeLayout&gt;
  
      &lt;requestFocus /&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p></p>
  
  <p>This is what I get:</p>
  
  <p><img src="https://i.stack.imgur.com/if2dg.png" alt="Result of the layout XML"></p>
  
  <p>How do I make it so that the button appears at the bottom of the screen or beyond. Upon searching online, most answers were to set the `android:fillViewport="true", but that is not helping. What am I doing wrong?</p>