App.js

import React, { useCallback, useEffect, useState } from 'react';
import { Platform, StatusBar, StyleSheet, View } from 'react-native';
import { Asset } from 'expo-asset';
import * as Font from 'expo-font';
import * as Icon from '@expo/vector-icons';
import * as SplashScreeen from 'expo-splash-screen';

import AppNavigator from './navigation/AppNavigator';

// Keep the splash screen visible while we fetch resources
SplashScreeen.preventAutoHideAsync();

export default function App() {
  const [appIsReady, setAppIsReady] = useState(false);

  useEffect(() => {
    async function prepare() {
      try {
        await Asset.loadAsync([
          require('./assets/images/logo-square.png'),
          require('./assets/images/logo.png'),
        ]);
        await Font.loadAsync({
          // This is the font that we are using for our tab bar
          ...Icon.Ionicons.font,
          // We include SpaceMono because we use it in HomeScreen.js. Feel free
          // to remove this if you are not using it in your app
          'space-mono': require('./assets/fonts/SpaceMono-Regular.ttf'),
        });

        await new Promise(resolve => setTimeout(resolve, 2000));
      } catch (e) {
        console.warn(e);
      } finally {
        setAppIsReady(true);
      }
    }

    prepare();
  }, []);

  const onLayoutRootView = useCallback(async () => {
    if (appIsReady) {
      await SplashScreeen.hideAsync();
    }
  }, [appIsReady]);

  if (!appIsReady) {
    return null;
  }

  return (
    <View style={styles.container}
      onLayout={onLayoutRootView}>
      {Platform.OS === 'ios' && <StatusBar barStyle="default" />}
      <AppNavigator />
    </View>
  );
}


const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
  },
});