push-notifications

Push Notification Patterns

iOS-related routing: for updating a Live Activity / Dynamic Island via an APNs push (content-state), use activitykit; for pushing widget timeline reloads, use widgetkit. This skill covers the FCM/APNs delivery + payload layer.

Android / Firebase Cloud Messaging

Firebase Setup

Add google-services.json to the app/ directory and configure dependencies:

// build.gradle.kts (project)
plugins {
    id("com.google.gms.google-services") version "4.5.0" apply false
}

// build.gradle.kts (app)
plugins {
    id("com.google.gms.google-services")
}

dependencies {
    implementation(platform("com.google.firebase:firebase-bom:34.18.0"))
    implementation("com.google.firebase:firebase-messaging")
}

The -ktx modules were removed in BoM 34.0.0 — all Kotlin extensions (Firebase.messaging, etc.) now live in the main artifacts. Do not add firebase-messaging-ktx.

Manifest Registration

Without the MESSAGING_EVENT intent filter the service is never invoked — this is the most common "onMessageReceived never fires" cause:

<service
    android:name=".MyFirebaseMessagingService"
    android:exported="false">
    <intent-filter>
        <action android:name="com.google.firebase.MESSAGING_EVENT" />
    </intent-filter>
</service>

<!-- Applies only to notification messages FCM renders itself (app backgrounded). -->
<meta-data android:name="com.google.firebase.messaging.default_notification_icon"
    android:resource="@drawable/ic_notification" />
<meta-data android:name="com.google.firebase.messaging.default_notification_color"
    android:resource="@color/notification_accent" />
<meta-data android:name="com.google.firebase.messaging.default_notification_channel_id"
    android:value="default" />

The channel named by default_notification_channel_id must already exist when the message arrives; otherwise FCM falls back to a generic SDK-created channel the user cannot meaningfully tune.