Notification handling in background in Firebase - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

How does Firebase Cloud Messaging handle notifications when the app is in the background on Android?

When a Firebase Cloud Messaging (FCM) notification is sent to an Android device and the app is in the background, what happens to the notification?

A The notification is automatically displayed in the system tray without invoking app code.

B The app receives the notification data immediately and processes it in the background service.

C The notification is discarded and not shown to the user.

D The app wakes up and shows a custom notification UI immediately.

💡 Hint

Think about how Android handles notifications when the app is not active.

When the app is in the background, FCM automatically displays the notification in the system tray without running app code. This ensures the user sees the notification even if the app is not active.

❓ Architecture

intermediate

Which Firebase service is best suited to trigger background notification handling logic?

You want to run custom code in the background when a notification arrives, even if the app is closed. Which Firebase service should you use?

A Firebase Cloud Functions triggered by Firestore changes

B Firebase Cloud Messaging data messages handled by a background service

C Firebase Realtime Database listeners in the foreground app

D Firebase Authentication triggers

💡 Hint

Consider which message type allows background processing on the device.

Data messages in FCM can be handled by background services on the device, allowing custom code execution even if the app is closed.

❓ security

advanced

What is a security risk when handling background notifications with data messages in Firebase?

When using Firebase Cloud Messaging data messages to handle notifications in the background, what security risk should you be aware of?

A Data messages automatically expose user credentials.

B Notifications can only be sent to authenticated users.

C Background services cannot access the internet.

D Data messages can be intercepted and modified if not encrypted.

💡 Hint

Think about data transmission security over networks.

Data messages are sent over the network and can be intercepted if not properly encrypted, risking data tampering or exposure.

❓ Configuration

advanced

Which manifest permission is required for background notification handling on Android with Firebase?

To receive Firebase Cloud Messaging data messages in the background on Android, which permission must be declared in the AndroidManifest.xml?

A <uses-permission android:name="android.permission.WAKE_LOCK" />

B <uses-permission android:name="android.permission.INTERNET" />

C <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

D <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />

💡 Hint

Consider what permission allows the app to keep the device awake to process messages.

The WAKE_LOCK permission allows the app to keep the CPU awake to process incoming messages in the background.

✅ Best Practice

expert

What is the best practice to ensure reliable background notification handling on iOS with Firebase?

On iOS, background notification handling is limited. Which approach best ensures your app processes notifications reliably in the background?

A Disable background modes to save battery and rely on user opening the app.

B Use local notifications scheduled by the app instead of remote notifications.

C Use silent push notifications with content-available flag and enable background fetch capability.

D Send only notification messages without data payload to wake the app.

💡 Hint

Think about how iOS allows apps to run code in the background.

Silent push notifications with the content-available flag allow the app to wake up in the background and process data if background fetch is enabled.