When Flatlist inside Scrollview, will have a warning:

virtualizedlists should never be nested inside plain scrollviews with the same orientation because it can break windowing and other functionality - use another virtualizedlist-backed container instead.

react-native-virtualized-view will resolve this problem.

    npm install react-native-virtualized-view --save

or

    yarn add react-native-virtualized-view

  import { FlatList } from 'react-native';
  import { ScrollView } from 'react-native-virtualized-view';

  return (
    <ScrollView>
      <FlatList />
      <FlatList />
    </ScrollView>
  )