expo-ui

# Expo UI (`@expo/ui`) ## When to Use Use this skill when you need build native UI with the @expo/ui package: real SwiftUI on iOS and Jetpack Compose on Android rendered from React in an Expo or React Native app. Covers universal cross-platform components (Host, Column, Row, Button, Text, List, and more imported from @expo/ui), drop-in replacements... `@expo/ui` renders real native UI from React: SwiftUI on iOS, Jetpack Compose on Android. Start with its universal components (one tree for iOS, Android, and web) and drop to platform-specific SwiftUI/Jetpack Compose only when the universal layer falls short. It also ships drop-in replacements for migrating off RN community UI libraries. > These instructions track the latest Expo SDK. The **universal** layer requires **SDK 56+**. Drop-in replacements and the platform-specific layers also exist on SDK 55. For component details on a specific SDK, refer to the Expo UI docs for that version. ## Installation ```bash npx expo install @expo/ui ``` On SDK 56, `@expo/ui` works in Expo Go, so `npx expo start` runs it directly — no custom build required. On older SDKs, build a dev client first (`npx expo run:ios` / `npx expo run:android`). Every `@expo/ui` tree — universal or platform-specific — must be wrapped in `Host`. ## Choosing an approach (read this first) Work down this list and stop at the first layer that meets the need: 1. **Universal components — start here.** Import from the `@expo/ui` root. One component tree runs unmodified on iOS, Android, and web from a single source (Compose on Android, SwiftUI on iOS, `react-native-web`/`react-dom` on web). No platform file splits. → `./references/universal.md` 2. **Platform-specific (SwiftUI / Jetpack Compose).** Import from `@expo/ui/swift-ui` or `@expo/ui/jetpack-compose`. Use **only** when the universal layer is missing a component or modifier you need, or when you need platform-specific behavior or optimization. **Downside:** you write two trees and split them into `.ios.tsx` / `.android.tsx` files (or branch on `Platform.OS`) — more code to maintain. > **`@expo/ui/swift-ui` is iOS-only. `@expo/ui/jetpack-compose` is Android-only.** Importing either in a file that runs on the other platform will crash at runtime with "Unable to get view config" errors. Isolate platform-specific trees in `.ios.tsx` / `.android.tsx` files placed in `components/` (never inside `app/` — Expo Router does not support platform extensions for route files), or guard with `Platform.OS` in a regular route file. `Host` must always be imported from `@expo/ui` (the universal package root), not from the platform-specific sub-packages. → `./references/swift-ui.md` and `./references/jetpack-compose.md` **Already using an RN community UI library?** `@expo/ui` also ships **drop-in replacements** — API-compatible swaps for popular libraries (`@gorhom/bottom-sheet`, `@react-native-community/datetimepicker`, and more), imported from `@expo/ui/community/<name>`. This is a migration side-path for replacing an existing dependency, not a step in the universal-vs-platform decision above. → `./references/drop-in-replacements.md` ## References Consult these resources as needed: ``` references/ universal.md Universal @expo/ui components and when to use them (SDK 56+) drop-in-replacements.md API-compatible replacements for RN community UI libraries swift-ui.md Platform-specific iOS UI: @expo/ui/swift-ui components, modifiers, RNHostView, useNativeState jetpack-compose.md Platform-specific Android UI: @expo/ui/jetpack-compose components, modifiers, LazyColumn caveat, icons, useNativeState ``` ## Limitations - Use this skill only when the task clearly matches its upstream product or API scope. - Verify commands, API behavior, pricing, quotas, credentials, and deployment effects against current official documentation before making changes. - Do not treat generated examples as a substitute for environment-specific tests, security review, or user approval for destructive or costly actions.