title: get coordinates when a textinput in react-native is in focus
body: <p>Can we get the x,y coordinates of TextInput when it is focused , i mean when the keyboard is shown ? </p>
  
  <p>Extending my above question, my actual question is how can we animate a TextInput into user visible area when that TextInput is in focus. What are the good approaches for it ? </p>
  
  <p>I have seen some approaches like <a href="https://github.com/jrans/react-native-smart-scroll-view/blob/master/complexFormExample.js" rel="nofollow">this</a> but it shrinks the TextInput. 
  Can anyone help me out there ? </p>