React Native Case Studies & Practical Application 3

Question 1

A banking app must lock itself immediately when the user leaves and return to the login screen. Which AppState value should trigger this?

Accepted Answer

'background'

Answer

The 'background' AppState triggers when the app is fully backgrounded, which is the correct moment to enforce security locks.

Question 2

A photo-sharing app uploads images to S3. Large uploads fail on slow connections. What technique improves reliability?

Accepted Answer

Use multipart/chunked upload with retry logic per chunk

Answer

Multipart chunked uploads allow retrying only failed chunks rather than restarting the entire upload on connection drops.

Question 3

A ride-sharing app needs to animate a car icon moving smoothly along a route on a map. Which API should drive the animation?

Accepted Answer

Animated.timing with useNativeDriver: true on coordinate values

Answer

Animated.timing with useNativeDriver offloads animation frames to the native thread, ensuring smooth 60fps motion without JS-thread involvement.

Question 4

A healthcare app must support biometric login (Face ID / fingerprint) on both iOS and Android. Which library provides a unified API?

Accepted Answer

expo-local-authentication

Answer

expo-local-authentication provides a cross-platform API for biometric authentication that works on both iOS and Android without platform-specific code.

Question 5

An event app needs deep linking so that tapping a link in an email opens the correct event detail screen. What must be configured?

Accepted Answer

A custom URL scheme in AndroidManifest.xml and Info.plist plus Linking API handling

Answer

Custom URL schemes require manifest entries on both platforms and runtime handling via the Linking API to navigate to the correct screen.

React Native Practice Test

React Native Practice Test

React Native Case Studies & Practical Application 3