App.js

import React from 'react'
import { Platform, StatusBar, StyleSheet, View } from 'react-native'
import { AppLoading, Asset, Font, Icon } from 'expo'
import AppNavigator from './navigation/AppNavigator'

export default class App extends React.Component {
  state = {
    isLoadingComplete: false,
  }

  async componentWillMount() {
    await Font.loadAsync({
      'Playfair Display': require('./assets/fonts/PlayfairDisplay-Bold.ttf'),
      Roboto: require('./assets/fonts/Roboto-Bold.ttf'),
    })
  }

  _handleLoadingError = error => {
    // In this case, you might want to report the error to your error
    // reporting service, for example Sentry
    console.warn(error)
  }

  _handleFinishLoading = () => {
    this.setState({ isLoadingComplete: true })
  }

  _loadResourcesAsync = async () =>
    Promise.all([
      Asset.loadAsync([
        require('./assets/images/robot-dev.png'),
        require('./assets/images/robot-prod.png'),
      ]),
      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
        Roboto: require('./assets/fonts/Roboto-Bold.ttf'),
      }),
    ])

  render() {
    if (!this.state.isLoadingComplete && !this.props.skipLoadingScreen) {
      return (
        <AppLoading
          startAsync={this._loadResourcesAsync}
          onError={this._handleLoadingError}
          onFinish={this._handleFinishLoading}
        />
      )
    }
    return (
      <View style={styles.container}>
        {Platform.OS === 'ios' && <StatusBar barStyle="default" />}
        <AppNavigator />
      </View>
    )
  }
}

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