text: import React from 'react';
  import { createStackNavigator, createButtomTopNavigator, createAppContainer } from 'react-navigation';
  import {Text, View} from 'react-native';
  
  import MainScreen from './MainScreen';
  import ChatRoomScreen from './ChatRoomScreen';
  import ChatStartScreen from './ChatStartScreen';
  import ChatScreen from './ChatScreen';
  import HistoryListScreen from './HistoryListScreen';
  import HistoryScreen from './HistoryScreen';
  
  const AppStackNavigator = createStackNavigator({
      Main: {
          screen: MainScreen
      }
  });
  
  export default createAppContainer(AppStackNavigator);