react-navigation/example/src/Shared/ButtonWithMargin.tsx

import * as React from 'react';
import { Platform, StyleSheet, View } from 'react-native';
import BaseButton, { ButtonProps } from './Button';

export const Button = (props: ButtonProps) => (
  <View style={styles.margin}>
    <BaseButton {...props} />
  </View>
);

const styles = StyleSheet.create({
  margin: {
    ...Platform.select({
      android: {
        margin: 10,
      },
    }),
  },
});