Firebase Cloud Messaging background notification channel ID not being set in Android O

Question

Firebase doesn't seem to be setting the Notification channelId on incoming messages to android M. I'm following this guide , and trying to get notifications to fire when my app is in the background.

Here's my app code and manifest.

public class MainActivity extends AppCompatActivity {

    private void registerNotificationChannel(String id, String name, String description) {
        NotificationManager mNotificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        int importance = NotificationManager.IMPORTANCE_HIGH;
        NotificationChannel mChannel = new NotificationChannel(id, name, importance);
        mChannel.setDescription(description);
        mChannel.enableLights(true);
        mChannel.setLightColor(Color.RED);
        mChannel.enableVibration(true);
        mChannel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
        mNotificationManager.createNotificationChannel(mChannel);
    }

    //private BroadcastReceiver isms;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d(TAG,"MainActivity.oncreate. token is:" +  FirebaseInstanceId.getInstance().getToken());

        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        registerNotificationChannel("default","default","all other notifications");
        registerNotificationChannel("channel1","channel1","notification channel 1");
        registerNotificationChannel("channel2","channel2","notification channel 2");
    }

    @Override protected void onDestroy() {
        super.onDestroy();
    }

}

public class MyFirebaseMessagingService extends FirebaseMessagingService {
    public void onMessageReceived(RemoteMessage remoteMessage) {
        Log.d(TAG, "firebase message received");
        if (remoteMessage.getNotification() != null) {
            Map<String,String> data = remoteMessage.getData();
            for (Map.Entry<String, String> entry : data.entrySet())
            {
                Log.d(TAG, "data: " + entry.getKey() + "/" + entry.getValue());
            }
            Log.d(TAG, "Message Notification Body: " + remoteMessage.getNotification().getBody());
        }

    }
}

    public class MyFirebaseInstanceIDService extends FirebaseInstanceIdService {
    @Override
    public void onTokenRefresh() {
        // Get updated InstanceID token.
        String refreshedToken = FirebaseInstanceId.getInstance().getToken();
        Log.d(TAG, "Refreshed firebase " +
                "" +
                "" +
                "token: " + refreshedToken);
    }
}

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.phauna.alerter">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <meta-data
            android:name="com.google.firebase.messaging.default_notification_channel_id"
            android:value="default"/>

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

    </application>

</manifest>

As you can see, I'm definitely registering my notification channels as it says here . This screenshot from my device confirms the channels are registered as well:

Here's the critical part. When I target API version 25, I get background notifications. As soon as I target version 26, I do not. Instead, I get this error message in logcat:

10-11 12:40:00.925   899  8910 E NotificationService: No Channel found for pkg=org.phauna.alerter, channelId=null, id=0, tag=GCM-Notification:286245598, opPkg=org.phauna.alerter, callingUid=10179, userId=0, incomingUserId=0, notificationUid=10179, notification=Notification(channel=null pri=0 contentView=null vibrate=null sound=content://settings/system/notification_sound defaults=0x0 flags=0x10 color=0x00000000 vis=PRIVATE)

I'm definitely setting a channel ID, as depicted in this screenshot sending from the Firebase console:

I have also tried sending through the HTTP service:

curl -X POST --header "Authorization: key=<redacted>" --Header "Content-Type: application/json" https://fcm.googleapis.com/fcm/send -d "{\"to\":\"<redacted>\",\"data\":{\"android_channel_id\":\"channel1\"},\"notification\":{\"body\":\"this is a testfoobar\"}}"

In both cases, the message reaches my device but does not have a channelId (as indicated by channelId=null in the above log message).

In the foreground, I can catch the notification with the service and manually stick a channel ID on it (even if I have to encode the channel ID in the payload of the message). But I need the background notifications to work as well, and as far as I know, that's up to the Firebase library to get right.

Answer 1

The Firebase Release Notes indicate that support for notification channels was added in version 10.2.6 (May 17, 2017):

Added support for Android O notification channels. Android clients can specify a default notification channel in the application manifest which will be used if the downstream message does not contain a notification_channel parameter.

Update your build to use version 10.2.6 or later.