这在颤动中意味着什么？

Question

我在初学者探索颤动的过程中遇到了这些代码

第一密码

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Helo world',
      theme: ThemeData(primarySwatch: Colors.cyan),
      home: HomePage(),
      routes: {
        "/fullPage": buildFullPage,
        "/form": buildFormPage,
        "/view": buildViewPage,
      },
    );
  }

第二个密码

void main() => runApp(MaterialApp(
      title: 'GridView Demo',
      home: SplashScreen(),
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.red,
        accentColor: Color(0xFF761322),
      ),
      routes: <String, WidgetBuilder>{
        SPLASH_SCREEN: (BuildContext context) => SplashScreen(),
        HOME_SCREEN: (BuildContext context) => HomeScreen(),
        //GRID_ITEM_DETAILS_SCREEN: (BuildContext context) => GridItemDetails(),
      },
    ));

我需要您的帮助，以了解这些多重路由

第一代码中的含义

home: HomePage(),
      routes: {
        "/fullPage": buildFullPage,
        "/form": buildFormPage,
        "/view": buildViewPage,
      },

这些在第二代码中的含义

home: SplashScreen(),
routes: <String, WidgetBuilder>{
        SPLASH_SCREEN: (BuildContext context) => SplashScreen(),
        HOME_SCREEN: (BuildContext context) => HomeScreen(),
        //GRID_ITEM_DETAILS_SCREEN: (BuildContext context) => GridItemDetails(),
      },