text: import { createStackNavigator } from 'react-navigation';
  import AddItemForm from '../components/AddItemForm';
  import UPCScanner from '../components/UPCScanner';
  import CameraView from '../components/CameraView';
  
  const StackNav = createStackNavigator({
    Form: AddItemForm,
    Scanner: UPCScanner,
    Camera: {
      screen: CameraView,
      navigationOptions: {
        header: null,
      },
    },
  },
  {
    headerMode: 'none',
    navigationOptions: {
      headerVisible: false,
    },
  });
  
  export default StackNav;
  