Java Android FirebaseMessagingService：根本没有调用onMessageReceived

Question

我的 FirebaseMessagingService java 类有问题。当我从 Firebase 控制台发送通知时，根本不会调用 onMessageReceived 函数。但我知道我成功发送了通知，这是我的代码：

package com.nufdev.firelink.other;

import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.media.RingtoneManager;
import android.net.Uri;
import android.support.v4.app.NotificationCompat;
import android.util.Log;

import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;
import com.nufdev.firelink.MainActivity;
import com.nufdev.firelink.R;

public class MyFirebaseMessagingService extends FirebaseMessagingService {
    private static final String TAG = "MyFirebaseMsgService";

    /**
     * Called when message is received.
     *
     * @param remoteMessage Object representing the message received from Firebase Cloud Messaging.
     */
    // [START receive_message]
    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {

        Log.d(TAG, "From: " + remoteMessage.getFrom());

        // Check if message contains a data payload.
        if (remoteMessage.getData().size() > 0) {
            Log.d(TAG, "Message data payload: " + remoteMessage.getData());
        }

        // Check if message contains a notification payload.
        if (remoteMessage.getNotification() != null) {
            Log.d(TAG, "Message Notification Body: " + remoteMessage.getNotification().getBody());
            sendNotification(remoteMessage.getNotification().getBody());

        }

        // Also if you intend on generating your own notifications as a result of a received FCM
        // message, here is where that should be initiated. See sendNotification method below.
    }
    // [END receive_message]

    /**
     * Create and show a simple notification containing the received FCM message.
     *
     * @param messageBody FCM message body received.
     */
    private void sendNotification(String messageBody) {
        Intent intent = new Intent(this, MainActivity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0 /* Request code */, intent,
                PendingIntent.FLAG_ONE_SHOT);

        Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
                .setSmallIcon(R.drawable.icon_send)
                .setContentTitle("FCM Message")
                .setContentText(messageBody)
                .setAutoCancel(true)
                .setSound(defaultSoundUri)
                .setContentIntent(pendingIntent);

        NotificationManager notificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

        notificationManager.notify(0 /* ID of notification */, notificationBuilder.build());
    }

    @Override
    protected Intent zzaa(Intent intent) {
        Log.v(TAG, "ZZZA?");
        return null;
    }
}  

每当我从 Firebase 控制台发送通知时，我只能在控制台中看到：ZZAA?因为这个：

@Override
        protected Intent zzaa(Intent intent) {
            Log.v(TAG, "ZZZA?");
            return null;
        }

我不知道zzaa 是什么意思，也无法在 Google 上找到它。
所以，如果你能帮助我，那就太棒了。 :D

Answer 1

也许您忘记将其添加到清单中（取自guide）

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

Answer 2

FCM 似乎有两种类型的通知消息。 FCM 控制台始终发送“通知消息”，仅当应用程序处于前台时才会触发 onMessageReceived。 有关该概念的更多详细信息：https://firebase.google.com/docs/cloud-messaging/concept-options

FCM 快速入门示例代码中的解释：

// [START receive_message]
@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
    // [START_EXCLUDE]
    // There are two types of messages data messages and notification messages. Data messages are handled
    // here in onMessageReceived whether the app is in the foreground or background. Data messages are the type
    // traditionally used with GCM. Notification messages are only received here in onMessageReceived when the app
    // is in the foreground. When the app is in the background an automatically generated notification is displayed.
    // When the user taps on the notification they are returned to the app. Messages containing both notification
    // and data payloads are treated as notification messages. The Firebase console always sends notification
    // messages. For more see: https://firebase.google.com/docs/cloud-messaging/concept-options
    // [END_EXCLUDE]

    // TODO(developer): Handle FCM messages here.
    // Not getting messages here? See why this may be: https://firebase.google.com/support/faq/#fcm-android-background
    Log.d(TAG, "From: " + remoteMessage.getFrom());