TabNavigator中没有内容

Question

不显示“标签”中的内容是什么原因？

我收到一个空白的白框。

当我只有Console.WriteLine("Please enter location"); var location = Console.ReadLine(); 而没有export const TopNavTabs时，它可以工作，但是我需要它作为组件。

class App

index.js

import React, { Component } from 'react'
import { Platform, View } from 'react-native'
import { TabNavigator } from 'react-navigation'

import General from './components/tabs/General'
import Help from './components/tabs/Help'
import Tips from './components/tabs/Tips'

export const TopNavTabs = TabNavigator({
  General: { screen: General },
  Help: { screen: Help },
  Tips: { screen: Tips },
},
{
  animationEnabled:true
});

export default class App extends Component{

  render(){
      return(
          <View>
            <TopNavTabs />
          </View>
      )
  }
}