title: getScrollY() always returns 0 in OnScrollChangedListener
body: <p>I have a GridLayout as follows:</p>
  
  <pre><code>&lt;GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/chat_layout"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:numColumns="auto_fit"
      android:columnCount="3"
      android:focusableInTouchMode="true"
      &gt;
  
      &lt;ScrollView
          xmlns:android="http://schemas.android.com/apk/res/android"
          android:id="@+id/chat_scroll"
          android:layout_width="match_parent"
          android:layout_height="0dp"
          android:layout_column="0"
          android:layout_row="0"
          android:layout_columnSpan="3"
          android:layout_gravity="fill"
          android:background="@drawable/chat_background"
          android:fillViewport="true"
          &gt;
  
          &lt;GridView
              android:id="@+id/message_grid"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:paddingStart="8dp"
              android:paddingEnd="8dp"
              android:paddingTop="8dp"
              android:paddingBottom="8dp"
              android:numColumns="1"
              /&gt;
  
      &lt;/ScrollView&gt;
  
      &lt;ImageView /&gt;
  
      &lt;EditText/&gt;
  
      &lt;ImageView/&gt;
  
  &lt;/GridLayout&gt;
  </code></pre>
  
  <p>I am trying to create an event when the <code>ScrollView</code> reaches the top by using the following code from <a href="https://stackoverflow.com/questions/10713312/can-i-have-onscrolllistener-for-a-scrollview/23365539#23365539">this answer</a> inside fragment</p>
  
  <pre><code>final ScrollView scrollView = (ScrollView) view.findViewById(R.id.chat_scroll);
  scrollView.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
  
      @Override
      public void onScrollChanged() {
          int scrollY = scrollView.getScrollY();
          Log.i(TAG, "scrollY: " + scrollY);
      }
  });
  </code></pre>
  
  <p>However, the problem is I am always getting the value of scrollY as 0.</p>