Importing Camera and rendering based on permissions.

App.js

import React from 'react';
import { StyleSheet, Text, View } from 'react-native';

// add this:
import { Camera, Permissions } from 'expo';

export default class App extends React.Component {
  // initialize state
  state = {
    cameraPermission: null
  };

  render() {
    const { cameraPermission } = this.state;

    // Render one of 3 things depending on permissions
    return (
      <View style={styles.container}>
        {cameraPermission === null ? (
          <Text>Waiting for permission...</Text>
        ) : cameraPermission === false ? (
          <Text>Permission denied</Text>
        ) : (
          <Text>yay camera</Text>
        )}
      </View>
    );
  }
}