Stack and Tab Navigator

Stack_Tab_Navigator.js

const FeedsStack = StackNavigator({
  Feeds: {
    screen: FeedsScreen,
    navigationOptions: {
      title: 'Feeds'
    },
  },
  Reader: {
    screen: ReaderScreen,
    navigationOptions: {
      title: 'Article'
    }
  },
});

const Root = TabNavigator (
  {
    Feeds: {
        screen: FeedsStack,
        navigationOptions: {
          tabBarLabel: 'Feeds',
          tabBarIcon: ({ tintColor }) => <Icon name='list' size={35} color={tintColor}/>
        },
    },
    Preferences: {
        screen: PreferencesScreen,
        navigationOptions: {
          tabBarLabel: 'Preferences',
          tabBarIcon: ({tintColor}) => <Icon name='account-circle' size={35} color={tintColor} />
        },
    },
  },
  {
    tabBarPosition: 'bottom',
    tabBarOptions: {
      style: {
        height: 50
      }
    }
  }
);