Gerenciando permissões de forma adequada
Verifique o status da permissão antes de solicitá-la, mostre uma explicação contextual ao usuário e reduza o recurso de forma adequada quando a permissão for negada.
Gerenciando permissões de forma adequada é uma aula grátis de React Native Academy no CoddyKit. Esta é a aula 4 de 4. Você pode ler a aula completa abaixo gratuitamente — depois pratica ao vivo no navegador com um editor de código integrado e um tutor de IA 24/7. Faz parte do caminho de aprendizado de React Native Academy, e seu progresso é sincronizado entre a web e o app CoddyKit. O curso de React Native Academy inclui 4 aulas no total.
Partes desta aula ainda não foram traduzidas e aparecem em inglês.
Why Permission Handling Matters
iOS and Android require explicit user consent before an app can access sensitive capabilities like the camera, location, microphone, or contacts. How you ask for and respond to permission decisions significantly affects user trust and app ratings. A poorly timed or unexplained permission request often results in denial, and once denied, the only recovery path is the device's Settings app.
Permission Lifecycle: The Four States
A permission can be in one of four states: undetermined (never asked yet), granted (user allowed it), denied (user said no during the last prompt), and restricted (iOS — blocked by parental controls, cannot be changed). Your app must handle each state correctly and never assume a permission is granted without checking.
import { PermissionStatus } from 'expo-location';
const { status } = await Location.getForegroundPermissionsAsync();
switch (status) {
case PermissionStatus.UNDETERMINED:
// Safe to call requestForegroundPermissionsAsync()
break;
case PermissionStatus.GRANTED:
// Proceed with the feature
break;
case PermissionStatus.DENIED:
// Show instructions to open Settings
break;
}Check Before Requesting
Always check the current permission status with a get*Async call before calling request*Async. If the permission is already granted, skip the request dialog. If it was already denied, do not re-prompt — iOS will silently ignore the request and Android will briefly flash a snackbar. Only prompt when status is undetermined.
async function ensureCameraPermission(): Promise<boolean> {
const { status } = await Camera.getCameraPermissionsAsync();
if (status === 'granted') return true;
if (status === 'undetermined') {
const { status: newStatus } = await Camera.requestCameraPermissionsAsync();
return newStatus === 'granted';
}
// status === 'denied' — direct user to Settings
return false;
}Contextual Pre-Permission Rationale
Before triggering the OS permission dialog, show the user a custom rationale screen that explains in plain language why your app needs the permission and how it benefits them. This 'prime' screen dramatically increases grant rates. It should appear right before the system dialog, not during onboarding before any feature context is established.
function LocationRationale({ onConfirm }: { onConfirm: () => void }) {
return (
<View style={styles.rationale}>
<Ionicons name='location-outline' size={48} color='#6200ee' />
<Text style={styles.title}>Share your location</Text>
<Text style={styles.body}>
We use your location to show nearby restaurants and
calculate accurate delivery times.
</Text>
<Button title='Allow Location' onPress={onConfirm} />
<Button title='Not Now' onPress={() => {}} color='gray' />
</View>
);
}Linking to App Settings When Denied
When a user has denied a permission and the feature cannot work without it, guide them to the device Settings app to manually grant it. Use Linking.openSettings() from React Native to open the app's settings page directly. Explain in an alert what they need to enable before calling openSettings.
import { Linking, Alert } from 'react-native';
function showSettingsPrompt(feature: string) {
Alert.alert(
feature + ' Access Denied',
'Please enable ' + feature + ' access in your device Settings to use this feature.',
[
{ text: 'Cancel', style: 'cancel' },
{ text: 'Open Settings', onPress: () => Linking.openSettings() },
]
);
}Graceful Degradation
Graceful degradation means your app still works — with reduced functionality — when a permission is denied. For example, a food delivery app denied location access can show a manual address input instead of auto-detecting the address. Design every permission-gated feature with a fallback path so no user is completely blocked from the app's core value.
export default function LocationPicker() {
const [permission] = Location.useForegroundPermissions();
const granted = permission?.granted;
if (granted) {
return <MapWithAutoLocation />; // use GPS
}
return <ManualAddressInput />; // fallback — type address manually
}canAskAgain: One Chance to Re-Request
The permission result object includes a canAskAgain property. On iOS, once the user taps 'Don't Allow' on the system dialog, canAskAgain becomes false and the system will never show the dialog again for that permission. On Android, it becomes false after the user denies twice. Always check this flag to decide whether to show the re-prompt button or the Settings link.
const { status, canAskAgain } = await Camera.requestCameraPermissionsAsync();
if (status !== 'granted') {
if (canAskAgain) {
// Show in-app explanation and re-request button
setShowRationale(true);
} else {
// Show link to Settings — OS won't show dialog again
showSettingsPrompt('Camera');
}
}Handling Multiple Permissions
Some features require multiple permissions simultaneously — for example a media picker needs both camera and media library access. Request them in sequence, checking each result before requesting the next. If any permission is denied, handle it and stop — do not proceed to the next request so users are not overwhelmed by multiple system dialogs in rapid succession.
async function requestMediaFeaturePermissions() {
const { status: cameraStatus } = await Camera.requestCameraPermissionsAsync();
if (cameraStatus !== 'granted') {
showSettingsPrompt('Camera');
return false;
}
const { status: mediaStatus } = await MediaLibrary.requestPermissionsAsync();
if (mediaStatus !== 'granted') {
showSettingsPrompt('Media Library');
return false;
}
return true;
}Persisting Permission State
You do not need to persist permission state in AsyncStorage — always query it fresh with get*Async calls because the user can change permissions in device Settings between app sessions. However, you can persist a flag like hasSeenPermissionRationale in AsyncStorage so you only show your custom rationale screen once and do not re-show it on every app launch.
async function maybeShowRationale() {
const seen = await AsyncStorage.getItem('seenLocationRationale');
if (!seen) {
setShowRationale(true);
await AsyncStorage.setItem('seenLocationRationale', 'true');
} else {
// Rationale seen before — go straight to checking permission
await checkLocationPermission();
}
}Testing Permission Flows
Test all four permission states: first launch (undetermined), granted, denied, and denied with canAskAgain=false. On iOS Simulator, reset permissions via Device Settings app. On Android Emulator, use App Info to revoke permissions manually. Also test the Settings link — make sure it opens the correct per-app settings page, not the general device settings screen.
A Reusable Permission Hook
Encapsulate the full permission lifecycle — check, rationale, request, and Settings fallback — into a reusable custom hook. The hook returns the current status and a function to trigger the permission request. This eliminates duplicated permission handling code across multiple screens that need the same capability.
function useCameraPermission() {
const [status, setStatus] = React.useState<string>('undetermined');
async function request() {
const { status: s, canAskAgain } = await Camera.requestCameraPermissionsAsync();
setStatus(s);
if (s !== 'granted' && !canAskAgain) {
showSettingsPrompt('Camera');
}
}
useEffect(() => {
Camera.getCameraPermissionsAsync().then(({ status: s }) => setStatus(s));
}, []);
return { status, granted: status === 'granted', request };
}Quick Check
Test your understanding of React Native Mobile Development concepts from this lesson.
Lesson Recap
In this lesson you learned: checking permission status before requesting prevents redundant system dialogs and handles already-denied states correctly, canAskAgain determines whether to re-prompt or direct users to Settings, and graceful degradation provides a fallback path so denied permissions don't completely block users from your app. Next up we explore forms and validation with react-hook-form.
Perguntas Frequentes
A aula “Gerenciando permissões de forma adequada” é grátis?
Sim — o texto completo de “Gerenciando permissões de forma adequada” é grátis para ler aqui na web. Para praticá-la interativamente (um editor de código integrado e um tutor de IA 24/7) e desbloquear o restante do curso de React Native Academy, atualize para CoddyKit PRO. O curso de React Native Academy inclui 4 aulas no total.
O que vou aprender em “Gerenciando permissões de forma adequada”?
Verifique o status da permissão antes de solicitá-la, mostre uma explicação contextual ao usuário e reduza o recurso de forma adequada quando a permissão for negada. Você pratica React Native Academy com código prático que executa diretamente no navegador, e um tutor de IA 24/7 responde suas dúvidas enquanto trabalha na aula.
Preciso ter experiência prévia para começar React Native Academy?
Nenhuma experiência prévia é necessária. React Native Academy no CoddyKit é estruturado para alunos iniciantes até avançados, então você pode começar aqui ou desde o início e aprender no seu ritmo. Esta é a aula 4 de 4.
Quanto tempo leva a aula “Gerenciando permissões de forma adequada”?
A maioria das aulas CoddyKit leva cerca de 5–10 minutos. Cada uma é compacta e interativa, então você faz progresso constante e retoma exatamente de onde parou entre web e app.
Posso escrever e executar código nesta aula de React Native Academy?
Sim. Cada aula de React Native Academy inclui um editor de código integrado, então você escreve e executa código real direto no navegador e recebe feedback de IA instantaneamente — nenhuma configuração local necessária.
Todas as aulas deste curso
- Acessando a câmera com expo-camera
- Lendo a localização GPS com expo-location
- Agendando notificações locais
- Gerenciando permissões de forma adequada