Make view 80% width of parent in React Native

As of React Native 0.42 height: and width: accept percentages.

Use width: 80% in your stylesheets and it just works.

• Screenshot
  
  

• Live Example
  Child Width/Height as Proportion of Parent

• Code

  import React from 'react';
  import { Text, View, StyleSheet } from 'react-native';
  
  const width_proportion = '80%';
  const height_proportion = '40%';
  
  const styles = StyleSheet.create({
    screen: {
      flex: 1,
      alignItems: 'center',
      justifyContent: 'center',
      backgroundColor: '#5A9BD4',
    },
    box: {
      width: width_proportion,
      height: height_proportion,
      alignItems: 'center',
      justifyContent: 'center',
      backgroundColor: '#B8D2EC',
    },
    text: {
      fontSize: 18,
    },
  });
  
  export default () => (
    <View style={styles.screen}>
      <View style={styles.box}>
        <Text style={styles.text}>
          {width_proportion} of width{'\n'}
          {height_proportion} of height
        </Text>
      </View>
    </View>
  );