IOS Expo Push Notifications when app is in foreground - react-native

Question

reading from the expo docs:
For iOS, you would be wise to handle push notifications that are
received while the app is foregrounded, because otherwise the user
will never see them. Notifications that arrive while the app are
foregrounded on iOS do not show up in the system notification list. A
common solution is to just show the notification manually. For
example, if you get a message on Messenger for iOS, have the app
foregrounded, but do not have that conversation open, you will see the
notification slide down from the top of the screen with a custom
notification UI.
What I don't understand is what is the best approach for that? is there an Expo API for showing such messages? or should I create an alert component of my own? It is not really clear from the docs.
Thanks.

Answer 1

This answer is outdated as of February 20, 2020. Please see https://stackoverflow.com/a/60344280/2441420 for how to show iOS Notification when your application is in the Foreground
There isn't an Expo API for showing those messages. You can use any 'toast' library of your choosing and display the notification message, but that should be all your code.
For example, this is how we are doing right now:
export default class HomeScreen extends React.Component {
componentDidMount() {
this.notificationSubscription = Notifications.addListener(
(notification) => this.handlePushNotification(notification),
);
}
handlePushNotification(notification) {
const { navigation } = this.props;
PushNotificationsService.handleNotification(notification, navigation);
}
(...)
import Toast from 'react-native-root-toast';
export default class PushNotificationsService {
static handleNotification(notification, navigation) {
if (notification.data.screen && notification.origin === 'selected') {
navigation.navigate(notification.data.screen);
}
Toast.show(notification.data.message);
}
}
Toast libraries include:
react-native-root-toast
react-native-easy-toast
react-native-simple-toast

Answer 2

Now you can just add that in one of your app entry point. The shouldShowAlert is what you want here
import * as Notifications from 'expo-notifications';
Notifications.setNotificationHandler({
handleNotification: async () => ({
shouldShowAlert: true,
shouldPlaySound: false,
shouldSetBadge: false,
}),
});

Answer 3

App.json :
{
"expo": {
"notification": {
"iosDisplayInForeground": true
}
}

Answer 4

DEMO
I'm not sure exactly when this was added to Expo, but as of Expo version 36 is easily doable.
To show Expo Push Notifications on iOS when your app is in the foreground, please do the following:
import { Vibration } from "react-native";
import { Notifications } from "expo";
import * as Permissions from "expo-permissions";
import Constants from "expo-constants";
registerForPushNotificationsAsync = async () => {
if (Constants.isDevice) {
const { status: existingStatus } = await Permissions.getAsync(
Permissions.NOTIFICATIONS
);
let finalStatus = existingStatus;
if (existingStatus !== "granted") {
const { status } = await Permissions.askAsync(
Permissions.NOTIFICATIONS
);
finalStatus = status;
}
if (finalStatus !== "granted") {
alert("Failed to get push token for push notification!");
return;
}
let token = await Notifications.getExpoPushTokenAsync();
console.log("Go to https://expo.io/notifications and copy the token below to easily send yourself a notification.");
console.warn("Notifications on iOS (and I believe Android) ONLY WORK ON A PHYSICAL DEVICE, not a simulator or emulator!!!")
console.log(token);
this.setState({ expoPushToken: token });
} else {
alert("Must use physical device for Push Notifications");
}
};
componentDidMount() {
this.registerForPushNotificationsAsync();
this._notificationSubscription = Notifications.addListener(
this._handleNotification
);
}
_handleNotification = async notification => {
if (notification.remote) {
Vibration.vibrate();
const notificationId = Notifications.presentLocalNotificationAsync({
title: "Follow #technoplato",
body: "To learn yourself goodly (also follow PewDiePie)",
ios: { _displayInForeground: true } // <-- HERE'S WHERE THE MAGIC HAPPENS
});
}
};
Quick and Easy Sanity Check
1) Go here: https://expo.io/notifications
2) Copy the token that is output to the terminal when your application is run.
3) Open your application on iOS.
4) Send a notification to yourself from https://expo.io/notifications and observe that it shows up even when your app is foregrounded.
Notes
Notifications WILL NOT BE RECEIVED ON AN IOS SIMULATOR
Expo makes Notifications ridiculously easy. I honestly can't believe it.
No idea why displayInForeground is false by default and not more prominent in the documentation. I'll submit a PR for it if I can.
Code originally found at this Snack: https://snack.expo.io/#documentation/pushnotifications?platform=ios
LocalNotification.ios._displayInForeground found here: https://docs.expo.io/versions/v36.0.0/sdk/notifications/#localnotification