我创建了模板的typescript世博会应用程序与导航选项卡，我找不到主文件，这是负责主屏幕。在创建的文件夹中没有App.ts，index.ts基本上为空。在package.json中没有入口点设置，我不知道在哪里可以检查主屏幕。这是我第一次使用expo和react-native app.json：

{
  "expo": {
    "name": "test_mobile_app",
    "slug": "test_mobile_app",
    "version": "1.0.0",
    "orientation": "portrait",
    "icon": "./assets/images/icon.png",
    "scheme": "myapp",
    "userInterfaceStyle": "automatic",
    "splash": {
      "image": "./assets/images/splash.png",
      "resizeMode": "contain",
      "backgroundColor": "#ffffff"
    },
    "assetBundlePatterns": [
      "**/*"
    ],
    "ios": {
      "supportsTablet": true
    },
    "android": {
      "adaptiveIcon": {
        "foregroundImage": "./assets/images/adaptive-icon.png",
        "backgroundColor": "#ffffff"
      }
    },
    "web": {
      "bundler": "metro",
      "favicon": "./assets/images/favicon.png"
    }
  }
}

index.ts:

import 'expo-router/entry';

package.json:

{
  "name": "test_mobile_app",
  "version": "1.0.0",
  "scripts": {
    "start": "expo start",
    "android": "expo start --android",
    "ios": "expo start --ios",
    "web": "expo start --web",
    "test": "jest --watchAll"
  },
  "jest": {
    "preset": "jest-expo"
  },
  "dependencies": {
    "@expo/vector-icons": "^13.0.0",
    "@react-native-community/slider": "^4.4.2",
    "@react-navigation/native": "6.0.8",
    "expo": "~48.0.15",
    "expo-font": "~11.1.1",
    "expo-linking": "~4.0.1",
    "expo-router": "^1.5.2",
    "expo-splash-screen": "~0.18.2",
    "expo-status-bar": "~1.4.4",
    "expo-system-ui": "~2.2.1",
    "expo-web-browser": "~12.1.1",
    "react": "18.2.0",
    "react-dom": "18.2.0",
    "react-native": "0.71.7",
    "react-native-safe-area-context": "4.5.0",
    "react-native-screens": "~3.20.0",
    "react-native-web": "~0.18.10"
  },
  "devDependencies": {
    "@babel/core": "^7.20.0",
    "@types/react": "~18.0.14",
    "jest": "^29.2.1",
    "jest-expo": "~48.0.0",
    "react-test-renderer": "18.2.0",
    "typescript": "^4.9.4"
  },
  "private": true
}

在“app”文件夹中有一个名为“_layout.tsx”的文件。我猜它是用作主屏幕文件，但我不确定。_layout.tsx：

import FontAwesome from '@expo/vector-icons/FontAwesome';
import { DarkTheme, DefaultTheme, ThemeProvider } from '@react-navigation/native';
import { useFonts } from 'expo-font';
import { SplashScreen, Stack } from 'expo-router';
import { useEffect } from 'react';
import { useColorScheme } from 'react-native';

export {
  // Catch any errors thrown by the Layout component.
  ErrorBoundary,
} from 'expo-router';

export const unstable_settings = {
  // Ensure that reloading on `/modal` keeps a back button present.
  initialRouteName: '(tabs)',
};

export default function RootLayout() {
  const [loaded, error] = useFonts({
    SpaceMono: require('../assets/fonts/SpaceMono-Regular.ttf'),
    ...FontAwesome.font,
  });

  // Expo Router uses Error Boundaries to catch errors in the navigation tree.
  useEffect(() => {
    if (error) throw error;
  }, [error]);

  return (
    <>
      {/* Keep the splash screen open until the assets have loaded. In the future, we should just support async font loading with a native version of font-display. */}
      {!loaded && <SplashScreen />}
      {loaded && <RootLayoutNav />}
    </>
  );
}

function RootLayoutNav() {
  const colorScheme = useColorScheme();

  return (
    <>
      <ThemeProvider value={colorScheme === 'dark' ? DarkTheme : DefaultTheme}>
        <Stack>
          <Stack.Screen name="(tabs)" options={{ headerShown: false }} />
          <Stack.Screen name="modal" options={{ presentation: 'modal' }} />
        </Stack>
      </ThemeProvider>
    </>
  );
}