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Benachrichtigungen im Vorder- und Hintergrund verarbeiten

Benachrichtigungen im Vorder- und Hintergrund verarbeiten ist eine kostenlose React Native Academy-Lektion auf CoddyKit. Dies ist Lektion 3 von 4. Du kannst die komplette Lektion unten kostenlos lesen – dann übst du sie direkt im Browser mit einem integrierten Code-Editor und einem KI-Tutor rund um die Uhr. Sie ist Teil des React Native Academy-Lernpfads, und dein Fortschritt wird über Web und CoddyKit-App synchronisiert. Der React Native Academy-Kurs umfasst insgesamt 4 Lektionen.

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App States and Notification Delivery

Your app can be in three states when a notification arrives: foreground (app is open and visible), background (app is running but not visible), or killed (app is not running at all). Each state has different handling requirements and different APIs to use.

Understanding which state applies is critical because the OS delivers notifications differently in each case and the user's tap response routes through different code paths depending on the app state at the time they tap.

addNotificationReceivedListener

Notifications.addNotificationReceivedListener fires when a notification arrives while the app is in the foreground. By default, notifications do not show a banner or sound when the app is already open — you must handle them in-app. The listener receives the full notification object including all content and data payload.

Use this to show in-app banners, update UI (e.g., refresh a chat thread), or play a custom sound — giving users the same experience as if the notification had arrived while the app was in the background.

import * as Notifications from 'expo-notifications';
import { useEffect } from 'react';

useEffect(() => {
  const subscription = Notifications.addNotificationReceivedListener(
    (notification) => {
      const { title, body, data } = notification.request.content;
      console.log('Notification received in foreground:', title, body);
      // Update UI or show in-app banner:
      showInAppBanner({ title, body });
    }
  );

  return () => subscription.remove();
}, []);

addNotificationResponseReceivedListener

Notifications.addNotificationResponseReceivedListener fires when the user taps a notification, regardless of whether the app was in the background or killed. The listener receives a response object that contains the notification, the action identifier (which button was tapped), and any user text input.

Use this to navigate to the relevant screen based on the notification's data payload. This is the most important notification handler because it drives the deep navigation behavior users expect when tapping a notification.

useEffect(() => {
  const subscription = Notifications.addNotificationResponseReceivedListener(
    (response) => {
      const { data } = response.notification.request.content;
      console.log('User tapped notification:', data);

      if (data.screen) {
        navigation.navigate(data.screen, { id: data.id });
      }
    }
  );

  return () => subscription.remove();
}, []);

Notification Data Payload Design

The data field in a push notification is your app's contract with itself — it determines what happens when the notification is tapped. Design a consistent schema that includes the destination screen name and all parameters that screen needs.

A well-designed data payload allows any notification to navigate to precisely the right screen with the right content without any guessing. Use type-safe constants for action types to prevent typos causing silent navigation failures.

// Consistent data payload schema:
const notificationData = {
  type: 'new_message',   // action type
  screen: 'Chat',        // destination screen name
  conversationId: 'abc', // screen params
  senderId: '123',
};

// Response handler:
const { type, screen, conversationId } = response.notification.request.content.data;

switch (type) {
  case 'new_message':
    navigation.navigate(screen, { conversationId });
    break;
  case 'order_update':
    navigation.navigate('OrderDetail', { orderId: data.orderId });
    break;
}

Foreground Notification Display Control

By default in expo-notifications, notifications received while the app is in the foreground are silent (no banner, no sound). Control this with the setNotificationHandler set at app startup. The handler function is async — you can even make an API call to decide whether to show a notification based on user preferences.

Return shouldShowAlert: true to show the system banner even when the app is open. This is appropriate for notifications from other users (messages) but often not for your own app's activity notifications.

Notifications.setNotificationHandler({
  handleNotification: async (notification) => {
    const { type } = notification.request.content.data;
    // Show banner for messages but not for own activity:
    return {
      shouldShowAlert: type !== 'own_activity',
      shouldPlaySound: type === 'new_message',
      shouldSetBadge: true,
    };
  },
});

Background Notification Handling on iOS

On iOS, you can configure background notifications (silent push notifications) that wake the app in the background to fetch data without showing a banner. Set content-available: 1 in the APNs payload. The app gets a short window (~30 seconds) to fetch data.

Background fetch is useful for pre-loading content before the user opens the app from a notification, ensuring the screen is ready instantly. Handle it with expo-notifications' background notification tasks using Expo's task manager.

import * as TaskManager from 'expo-task-manager';
import * as Notifications from 'expo-notifications';

const BACKGROUND_NOTIFICATION_TASK = 'background-notification';

TaskManager.defineTask(BACKGROUND_NOTIFICATION_TASK,
  async ({ data: { notification }, error }) => {
    if (error) return;
    // Fetch fresh data silently in the background:
    await prefetchDataForNotification(notification.request.content.data);
  }
);

Notifications.registerTaskAsync(BACKGROUND_NOTIFICATION_TASK);

Notification Action Buttons

Notifications can include action buttons that let users respond without opening the app. For example, a message notification might have 'Reply' and 'Mark Read' buttons. Configure categories with Notifications.setNotificationCategoryAsync and reference the category in your push payload.

The tap response listener's response.actionIdentifier tells you which button was tapped. For text input actions, response.userText contains what the user typed directly from the notification.

// Define notification category with actions:
await Notifications.setNotificationCategoryAsync('message', [
  {
    identifier: 'reply',
    buttonTitle: 'Reply',
    textInput: { submitButtonTitle: 'Send', placeholder: 'Type a reply...' },
  },
  {
    identifier: 'mark_read',
    buttonTitle: 'Mark as Read',
    isDestructive: false,
  },
]);

// In response listener:
if (response.actionIdentifier === 'reply') {
  sendReply(response.userText, messageId);
}

Managing Badge Count

The badge count is the red number on your iOS app icon. Set it by including a badge number in your push payload, or update it from within the app using Notifications.setBadgeCountAsync(count). Reduce the badge when the user reads notifications or visits the relevant screen.

A common pattern: server sets badge to unread count when sending a push, and app calls setBadgeCountAsync(0) when the user opens the inbox. Always fetch the true unread count from your server rather than incrementing a local counter, since multiple devices must stay in sync.

import * as Notifications from 'expo-notifications';

// Clear badge when user opens inbox:
async function clearBadge() {
  await Notifications.setBadgeCountAsync(0);
}

// Get current badge count:
const count = await Notifications.getBadgeCountAsync();
console.log('Current badge:', count);

// Update badge from server-returned unread count:
async function updateBadge(unreadCount) {
  await Notifications.setBadgeCountAsync(unreadCount);
}

Dismissing Displayed Notifications

After reading a notification in-app, you should dismiss the corresponding notification from the notification center so it doesn't mislead the user. Use Notifications.dismissNotificationAsync(identifier) for a specific notification or Notifications.dismissAllNotificationsAsync() to clear all.

Call dismiss in the notification response handler after navigating to the relevant screen, or in useEffect on the target screen when it mounts. The notification identifier is available in the response object.

const subscription = Notifications.addNotificationResponseReceivedListener(
  async (response) => {
    const { data } = response.notification.request.content;
    const notifId = response.notification.request.identifier;

    // Navigate to relevant screen:
    navigation.navigate(data.screen, { id: data.id });

    // Dismiss the notification from notification center:
    await Notifications.dismissNotificationAsync(notifId);
  }
);

Getting All Pending Notifications

Retrieve all currently displayed notifications in the notification center with Notifications.getPresentedNotificationsAsync(). Use this on app launch to handle any notifications the user hasn't tapped yet, or to display an unread count badge based on actual notification center contents.

On app foreground, you can also loop through pending notifications and dismiss ones that are now stale (e.g., expired promotions or events that have passed).

useEffect(() => {
  // When app comes to foreground:
  async function cleanupStaleNotifications() {
    const displayed = await Notifications.getPresentedNotificationsAsync();
    const now = Date.now();

    for (const notif of displayed) {
      const { expiresAt } = notif.request.content.data;
      if (expiresAt && expiresAt < now) {
        await Notifications.dismissNotificationAsync(notif.request.identifier);
      }
    }
  }
  cleanupStaleNotifications();
}, [appState]);

A Complete Notification Handler Setup

A production-ready notification setup combines all the pieces: set the handler at startup, register listeners in a custom hook, and wire them to navigation. The custom hook handles both foreground (show banner, update state) and tap responses (navigate), and always cleans up listeners on unmount.

This architecture keeps notification logic centralized, testable, and separate from individual screen components.

function useNotifications(navigation) {
  useEffect(() => {
    const received = Notifications.addNotificationReceivedListener(
      (notif) => handleForeground(notif)
    );
    const response = Notifications.addNotificationResponseReceivedListener(
      (resp) => handleTap(resp, navigation)
    );
    return () => {
      received.remove();
      response.remove();
    };
  }, [navigation]);
}

// Use in root component:
const navigation = useNavigation();
useNotifications(navigation);

Quick Check

Test your understanding of React Native Mobile Development concepts from this lesson.

Lesson Recap

In this lesson you learned: addNotificationReceivedListener handles notifications arriving while the app is in the foreground, addNotificationResponseReceivedListener handles user taps on notifications from any app state and should navigate to the relevant screen, and action buttons with categories enable users to reply or take actions directly from the notification without opening the app. Next up we configure notification channels and add rich content like images and action buttons.

Häufig gestellte Fragen

Ist die Lektion „Benachrichtigungen im Vorder- und Hintergrund verarbeiten“ kostenlos?

Ja — der vollständige Text von „Benachrichtigungen im Vorder- und Hintergrund verarbeiten“ ist hier im Web kostenlos zu lesen. Um sie interaktiv zu üben (integrierter Code-Editor und 24/7 KI-Tutor) und den Rest des React Native Academy-Kurses freizuschalten, upgrade auf CoddyKit PRO. Der React Native Academy-Kurs umfasst insgesamt 4 Lektionen.

Was lerne ich in „Benachrichtigungen im Vorder- und Hintergrund verarbeiten“?

Verwenden Sie addNotificationReceivedListener, um Benachrichtigungen zu verarbeiten, während die App geöffnet ist, und addNotificationResponseReceivedListener, um auf das Tippen des Benutzers auf ein… Du übst React Native Academy mit praktischem Code, den du direkt im Browser ausführst, und ein 24/7 KI-Tutor beantwortet deine Fragen während du die Lektion bearbeitest.

Brauche ich Erfahrung, um React Native Academy zu starten?

Keine Vorkenntnisse erforderlich. React Native Academy auf CoddyKit ist für Anfänger bis fortgeschrittene Lernende strukturiert, sodass du hier starten oder von Anfang an beginnen und in deinem eigenen Tempo voranschreiten kannst. Dies ist Lektion 3 von 4.

Wie lange dauert die Lektion „Benachrichtigungen im Vorder- und Hintergrund verarbeiten“?

Die meisten CoddyKit-Lektionen dauern etwa 5–10 Minuten. Jede ist kompakt und interaktiv, sodass du stetig Fortschritte machst und genau dort weitermachst, wo du aufgehört hast – im Web und in der App.

Kann ich in dieser React Native Academy-Lektion Code schreiben und ausführen?

Ja. Jede React Native Academy-Lektion enthält einen integrierten Code-Editor, sodass du echten Code direkt in deinem Browser schreibst und ausführst und sofort KI-Feedback erhältst — ohne lokale Einrichtung erforderlich.

Alle Lektionen in diesem Kurs

Berechtigungen anfordern und einen Push-Token abrufen
Benachrichtigungen über die Expo Push API senden
Benachrichtigungen im Vorder- und Hintergrund verarbeiten
Benachrichtigungskanäle und Rich Content

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