Detect coming back from app settings/background with React Native - react-native

Question

My app asks permission to use location services.
If a user denies permission, they can click a button to go to the settings page and grant permissions.
On ios, they are given the option to return directly to the app. on Android, I think they can do something similar.
Is there a way to detect arriving back at the app so I can check their permissions again?
I've tried with React Navigation's useFocusEffect hook:
useFocusEffect(
React.useCallback(() => {
console.log("navigated")
return () => getPosition()
}, [])
)
But unfortunately, that only works when navigating between screens/routes in the app.
Is there a way to detect the app transitioning from background to foreground?

Answer 1

You can track app state with https://reactnative.dev/docs/appstate
in pseudo-code: if previously 'background' and now 'active' then run your effects

Answer 2

Ciao, when I want to manage permission, I use react-native-permissions. In this way you can manage all permissions directly in your app without exit from it.
Works well for iOs and Android. In your case, you could something like:
import {check, PERMISSIONS, RESULTS} from 'react-native-permissions';
check(<permission you need>)
.then((result) => {
switch (result) {
case RESULTS.UNAVAILABLE:
console.log(
'This feature is not available (on this device / in this context)',
);
break;
case RESULTS.DENIED:
console.log(
'The permission has not been requested / is denied but requestable',
);
break;
case RESULTS.GRANTED:
console.log('The permission is granted');
break;
case RESULTS.BLOCKED:
console.log('The permission is denied and not requestable anymore');
break;
}
})
.catch((error) => {
// …
});

Answer 3

Use this hook:
// hooks/useAppIsActive.ts
import { useCallback, useEffect, useRef } from "react";
import { AppState } from "react-native";
export default (callback: Function) => {
const appStateRef = useRef(AppState.currentState);
const handleAppStateChange = useCallback((nextAppState) => {
if (
appStateRef.current.match(/inactive|background/) &&
nextAppState === "active"
) {
callback();
}
appStateRef.current = nextAppState;
}, []);
useEffect(() => {
AppState.addEventListener("change", handleAppStateChange);
return () => {
AppState.removeEventListener("change", handleAppStateChange);
};
}, []);
};
And from the component you want to detect "the come back", pass by parameter the callback you want to run:
const MyView = () => {
const requestLocationAccess = useCallback(() => {
// request permissions...
}, [])
useAppIsActive(() => requestLocationAccess());
}