day1.js

import React from 'react';
import { View, Text, Dimensions, StyleSheet } from 'react-native';

const Dev_Height = Dimensions.get('window').height;
const Dev_Width = Dimensions.get('window').width;

class App extends React.Component {
  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.vishnu}>Hello World</Text>
        <View style={styles.subbox}>
        <Text style={styles.vishnu}>test</Text>
        </View>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    height: Dev_Height,
    width: Dev_Width,
    backgroundColor: '#7F6DF3',
    alignItems:"center",
  },
  vishnu: {
    fontSize: 18,
    color: '#FFF',
    fontStyle: 'bold',
  },
  subbox:{
    height:"10%",
    width:"80%",
    backgroundColor:"#000",
    marginTop:"10%",
    marginLeft:"20%",
    justifyContent:"center",
    alignItems:"center"
  }
});

export default App;