const Components = {
 HomeTwo: { screen: HomeTwo, path:'app/HomeTwo' },
 HomeThree: { screen: HomeThree, path:'app/HomeThree' },
 BillTwo: { screen: BillTwo, path:'app/BillTwo' },
 BillThree: { screen: BillThree, path:'app/BillThree' },
}

const Tabs = TabNavigator({
 Home: {
  screen: Home,
  path:'app/home',
  navigationOptions: { 
  tabBar: {
   label: '首頁',
   icon: ({tintColor}) => (),
  },
  }
 },
 Bill: {
  screen: Bill,
  path:'app/bill',
  navigationOptions: {
  tabBar: {
   label: '賬單',
   icon: ({tintColor}) => (),
  },
  }
 },
 Me: {
  screen: Me,
  path:'app/me',
  navigationOptions: {
  tabBar: {
   label: '我',
   icon: ({tintColor}) => (),
  },
  }
 }
 }, {
 tabBarPosition: 'bottom', 
 swipeEnabled: false,
 animationEnabled: false, 
 lazyLoad: false, 
 backBehavior: 'none', 
 tabBarOptions: {
  activeTintColor: '#ff8500', 
  inactiveTintColor: '#999',
  showIcon: true, 
  indicatorStyle: {
  height: 0 
  },
  style: {
  backgroundColor: '#fff', 
  },
  labelStyle: {
  fontSize: 10, 
  },
 },
 });


 const Navs = StackNavigator({
 Home: { screen: Tabs, path:'app/Home' },
 Bill: { screen: Tabs, path:'app/Bill' },
 Me: { screen: Tabs, path:'app/Me' },
 ...Components
 }, {
 initialRouteName: 'Home', 
 navigationOptions: { 
  header: { 
  style: {
   backgroundColor: '#fff'
  },
  titleStyle: {
   color: 'green'
  }
  },
  cardStack: { 
  gesturesEnabled: true
  }
 },
 mode: 'card', 
 headerMode: 'screen'
 });

// push BillTwo
this.props.navigation.dispatch(resetAction);

// 使用reset action重置路由
const resetAction = NavigationActions.reset({
 index: 1, // 注意不要越界
 actions: [ // 棧里的路由信息會從 Home->HomeTwo 變成了 Bill->BillTwo
 NavigationActions.navigate({ routeName: 'Bill'}),
 NavigationActions.navigate({ routeName: 'BillTwo'})
 ]
});