title: ReactNative,How to get position FlatList Item in ScrollView
body: <p>I would like to scroll the parent <code>ScrollView</code> to that item<code>position</code> when I click Item in <code>FlatList</code>.</p>
  
  <p>Since the actual data is flexible in length, can not calculate the height statically.</p>
  
  <pre><code>&lt;ScrollView&gt;
    &lt;View style={{height:300}}&gt;
      &lt;Text&gt;Test&lt;/Text&gt;
    &lt;/View&gt;
    &lt;FlatList
      scrollEnabled={false}
      data={[1,2,3,4,5,6,7,8,9,10]}
      renderItem={renderItem}
    /&gt;
  &lt;/ScrollView&gt;
  </code></pre>
  
  <p><code>ScrollToIndex</code> in a <code>FlatList</code> can not be used because <code>scrollEnabled</code> is <code>false</code>.
  I want to use <code>ScrollTo</code> of the parent <code>ScrollView</code>.</p>
  
  <p>But <code>onLayout</code> is used for<code>renderItem</code>, <code>y</code> is 0.
  So I do not know the exact position.</p>
  
  <p>How can I get the value I want?</p>