title: React Native detect if a component is dragged into another component
body: <p>I need to detect if component A's position is within component B when pan gesture (drag) on A is released. </p>
  
  <p>However, the position from <code>onPanResponderRelease</code>'s <code>gesture.moveY</code> is measured with respect to the entire screen, whereas the position returned from A's <code>onLayout</code>is measured with respect to the parent view. </p>
  
  <p>So i'd need to know the parent view's current height to reconcile the differences. Is there a better way to do this?</p>