App.js

import React, { useEffect } from 'react';
import { View, ActivityIndicator } from 'react-native';
import { 
  NavigationContainer, 
  DefaultTheme as NavigationDefaultTheme,
  DarkTheme as NavigationDarkTheme
} from '@react-navigation/native';
import { createDrawerNavigator } from '@react-navigation/drawer';

import { 
  Provider as PaperProvider, 
  DefaultTheme as PaperDefaultTheme,
  DarkTheme as PaperDarkTheme 
} from 'react-native-paper';


import RootStackScreen from './src/Screens/RootStackScreen';

const App = () => {

  const [isDarkTheme, setIsDarkTheme] = React.useState(false);

  const CustomDefaultTheme = {
    ...NavigationDefaultTheme,
    ...PaperDefaultTheme,
    colors: {
      ...NavigationDefaultTheme.colors,
      ...PaperDefaultTheme.colors,
      background: '#ffffff',
      text: '#333333'
    }
  }
  
  const CustomDarkTheme = {
    ...NavigationDarkTheme,
    ...PaperDarkTheme,
    colors: {
      ...NavigationDarkTheme.colors,
      ...PaperDarkTheme.colors,
      background: '#333333',
      text: '#ffffff'
    }
  }

  const theme = isDarkTheme ? CustomDarkTheme : CustomDefaultTheme;

  return (
    <PaperProvider theme={theme}>
      <NavigationContainer theme={theme}>
        <RootStackScreen/>
      </NavigationContainer>
    </PaperProvider>
  );
}

export default App;