//import libraries to create components
import React from 'react'
import { Text, StyleSheet, View, SafeAreaView, StatusBar } from 'react-native'

//create a component that return some jsx/simple function
//======following code use SafeAreaView and statusBar.currentHeight to 
//    solve this problem===============================
const App = () => {
  return (
    <SafeAreaView style={styles.container}>
      <Text style={styles.textStyle}>hello world</Text>
    </SafeAreaView>
  )
}

//Create a StyleSheet object to style the component
const styles = StyleSheet.create({
  container: {
    flex: 1,
    marginTop: StatusBar.currentHeight || 0,
  },
})

//export the component, so it can be used in other parts of the app
export default App