how to make a screen scrollable in react native code example

Example 1: how to detect onend reach of scrollview in react native

import React from 'react';
import {ScrollView, Text} from 'react-native';

const isCloseToBottom = ({layoutMeasurement, contentOffset, contentSize}) => {
  const paddingToBottom = 20;
  return layoutMeasurement.height + contentOffset.y >=
    contentSize.height - paddingToBottom;
};

const MyCoolScrollViewComponent = ({enableSomeButton}) => (
  <ScrollView
    onScroll={({nativeEvent}) => {
      if (isCloseToBottom(nativeEvent)) {
        enableSomeButton();
      }
    }}
    scrollEventThrottle={400}
  >
    <Text>Here is very long lorem ipsum or something...</Text>
  </ScrollView>
);

export default MyCoolScrollViewComponent;

Example 2: auto scroll to view react-native

<ScrollView ref={view => this._scrollView = view} />
And set the scroll position elsewhere with:

scrollToRow(itemIndex) {
  this._scrollView.scrollTo({y:itemIndex * ROW_HEIGHT});
}