App gracefully handles permission denials

A permission denial is a user's explicit choice to restrict access — an app that crashes in response to that choice punishes the user for exercising their privacy preference. This is both a UX failure and a reliability issue captured by CWE-391 (Unchecked Error Condition) and ISO 25010 reliability fault-tolerance requirements. On iOS, once a user denies a permission, the native dialog never appears again — the app must handle the BLOCKED state and guide the user to Settings. An app that shows a generic error message with no Settings deep-link leaves the user with no path forward. The pattern of crashing on denial also causes 1-star reviews specifically citing privacy concerns, compounding the trust damage.

Handle all three permission states — GRANTED, DENIED, BLOCKED — for every permission-gated feature. For BLOCKED state, always provide a direct Settings deep-link.

import { request, check, PERMISSIONS, RESULTS, openSettings } from 'react-native-permissions'

async function activateCameraFeature() {
  const status = await check(
    Platform.OS === 'ios' ? PERMISSIONS.IOS.CAMERA : PERMISSIONS.ANDROID.CAMERA
  )

  switch (status) {
    case RESULTS.GRANTED:
      startCamera()
      break
    case RESULTS.DENIED:
      const result = await request(
        Platform.OS === 'ios' ? PERMISSIONS.IOS.CAMERA : PERMISSIONS.ANDROID.CAMERA
      )
      if (result === RESULTS.GRANTED) startCamera()
      break
    case RESULTS.BLOCKED:
      Alert.alert(
        'Camera Access Required',
        'Camera access was denied. Open Settings to enable it.',
        [{ text: 'Open Settings', onPress: openSettings }, { text: 'Cancel' }]
      )
      break
    default:
      // Feature unavailable — disable UI element, do not crash
      setFeatureAvailable(false)
  }
}