sso-poc-marn/app/_layout.tsx

import FontAwesome from '@expo/vector-icons/FontAwesome';
import {DarkTheme, DefaultTheme, ThemeProvider} from '@react-navigation/native';
import {useFonts} from 'expo-font';
import {Stack} from 'expo-router';
import * as SplashScreen from 'expo-splash-screen';
import {useEffect} from 'react';

import {useColorScheme} from '@/components/useColorScheme';
import {View} from "react-native";

export {
    // Catch any errors thrown by the Layout component.
    ErrorBoundary,
} from 'expo-router';

export const unstable_settings = {
    // Ensure that reloading on `/modal` keeps a back button present.
    initialRouteName: 'index',
};

// Prevent the splash screen from auto-hiding before asset loading is complete.
SplashScreen.preventAutoHideAsync();

export default function RootLayout() {
    const [loaded, error] = useFonts({
        SpaceMono: require('../assets/fonts/SpaceMono-Regular.ttf'),
        ...FontAwesome.font,
    });

    // Expo Router uses Error Boundaries to catch errors in the navigation tree.
    useEffect(() => {
        if (error) throw error;
    }, [error]);

    useEffect(() => {
        if (loaded) {
            SplashScreen.hideAsync();
        }
    }, [loaded]);

    if (!loaded) {
        return null;
    }

    return <RootLayoutNav/>;
}

function RootLayoutNav() {
    const colorScheme = useColorScheme();

    return (
        <View style={{
            flex: 1,
            justifyContent: 'center',
            alignItems: 'center',
        }}>
            <View style={{
                flex: 1,
                width: '100%',
            }}>
                <ThemeProvider value={colorScheme === 'dark' ? DarkTheme : DefaultTheme}>
                    <Stack>
                        <Stack.Screen name="index" options={{headerShown: false}}/>
                        <Stack.Screen name="ssoCallback" options={{headerShown: false}}/>
                        <Stack.Screen name="ssoLogout" options={{headerShown: false}}/>
                    </Stack>
                </ThemeProvider>
            </View>
        </View>
    );
}